Manipulator Head and Negative Pressure System

Abstract

The present invention relates to pumping a liquid (18) in a vacuum system under negative pressure, in particular under absolute pressures of less than 600 mbar. To this end, a manipulator head (10') is provided for use in a vacuum housing under negative pressure. The manipulator head (10') comprises a liquid cell (12) and a liquid pump (14). The liquid cell (12) comprises a liquid cell outlet (22) and an interior space (16) configured for negative pressure and adapted to contain a liquid (18). The liquid pump (14) comprises a liquid pumping region (26) fluidly connected to the liquid cell outlet (22) and configured for pumping the liquid (18) from the liquid pumping region (26) under negative pressure in the interior space (16) of the liquid cell (12). The distance (d') between the liquid cell outlet (22) of the liquid cell (12) and the liquid pumping area (26) of the liquid pump (14) is selected such that, at an absolute pressure of less than 600 mbar in the internal space (16) of the liquid cell (12), the liquid (18) extends at least into the liquid pumping area (26) of the liquid pump (14), so that the liquid pump (14) can pump the liquid (18). This allows a compact construction for a negative pressure system in which the liquid (18) can be circulated, and in particular emptied, at an absolute pressure of less than 600 mbar.

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present invention relates to a manipulator head for use in a negative pressure housing at negative pressure, a manipulator with a manipulator head, a negative pressure system with a manipulator head, as well as a method for manufacturing a manipulator head, a method for operating a negative pressure system and the use of a negative pressure system and the use of a method for operating a negative pressure system. In particular, the present invention relates to the filling and emptying of electrochemical cells at absolute pressures below 600 mbar, for example below 400 mbar, in particular below 100 mbar.

[0002] Prior Art From the Operating Instructions V.1.0 dated 06.02.2020 for the product O-EC-NAP Operando Electrochemical Cell of the company SPECS Surface Nano Analysis GmbH, a negative pressure system is known, in which an electrochemical cell is arranged in a negative pressure housing in such a way that measurements in the electrochemical cell can be carried out at negative pressure. The electrochemical cell is filled with a water-based electrolyte so that measurements in the sample electrode and in the water-based electrolyte can be carried out. To empty the water-based electrolyte of the electrochemical cell, a peristaltic pump is arranged outside the negative pressure housing, which can pump the water-based electrolyte out of the electrochemical cell at an absolute pressure of 600 mbar or more in the negative pressure housing. To empty the electrochemical cell, the absolute pressure is increased in the negative pressure housing until the water-based electrolyte can be pumped out of the electrochemical cell.

[0003] WO 01 / 16486 shows a peristaltic pump with a pump mechanism within a vacuum chamber. The placement of the pump mechanism within the vacuum chamber reduces the pressure difference between the inside and outside of the pump passage, thereby minimizing changes in the trapped fluid volume.

[0004] Description of the Invention It can be considered as an objective of the present invention to define a manipulator head, a manipulator equipped with the manipulator head and a negative pressure system equipped with the manipulator head, as well as corresponding methods for manufacturing the manipulator head and a method for operating a negative pressure system equipped with the manipulator head, which make it possible to pump liquids at absolute pressures of less than 600 mbar.

[0005] According to a first aspect of the invention, a manipulator head is provided that is configured for use in a negative pressure housing under negative pressure conditions. The manipulator head comprises a liquid cell and a liquid pump. The liquid cell comprises a liquid cell outlet and an internal space configured for receiving a liquid and configured for negative pressure. The liquid pump comprises a liquid pumping region fluidly connected to the liquid cell outlet and configured for pumping liquid from the liquid pumping region under negative pressure conditions in the internal space of the liquid cell. A distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump is selected such that the liquid extends at least to the liquid pumping region of the liquid pump, whereby the liquid pump is able to pump liquid under absolute pressure conditions of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar, in the internal space of the liquid cell.

[0006] Negative pressure is understood here as an absolute pressure lower than atmospheric pressure, i.e. the negative pressure is an absolute pressure lower than atmospheric pressure, for example less than 1013.25 mbar or 1 atm. The negative pressure in the inner space of the liquid cell may be, for example, an absolute pressure between 0.1 mbar and less than 600 mbar. Preferably, the absolute pressure in the inner space of the liquid cell may be between 0.1 mbar and 100 mbar.

[0007] The internal space of the liquid cell may be fluidly connected to the periphery of the manipulator head, i.e. gas and liquid can be exchanged between the internal space of the liquid cell and the periphery of the manipulator head. For this purpose, the liquid cell may have, for example, an opening to the periphery of the manipulator head, so that when the manipulator head is arranged in the negative pressure housing, the pressure in the internal space of the liquid cell can be adjusted via the operating pressure in the negative pressure housing.

[0008] The manipulator head can be arranged, for example, in a vacuum housing of a vacuum system, which is operated near the vapor pressure equilibrium of the liquid, thereby defining the pressure acting on the surface of the liquid or the operating pressure at a fixed temperature. At such low operating pressures, the liquid cannot flow out solely on the basis of the operating pressure in vacuum systems known from the prior art, depending on further parameters, such as, for example, the density of the liquid, the viscosity of the liquid, the inner diameter of the liquid line between the liquid line outlet and the liquid pumping area or the inner diameter of the liquid line for leading out the liquid, the material of the liquid line, the length of the liquid line, etc. If it is desired to replace the liquid, the operating pressure must be increased in vacuum systems known from the prior art, which leads to an interruption of the operation, for example, the measurement, for example.

[0009] In order for the liquid pump to be able to pump the liquid out, the liquid must extend into the liquid pumping area of ​​the liquid pump. The inventors have realized that the operating pressure alone cannot ensure this, if the liquid cell outlet of the liquid cell of the negative pressure system known from the prior art has an excessively large distance relative to the liquid pumping area of ​​the liquid pump. In this case, the pressure loss in the line between the liquid cell outlet and the liquid pumping area of ​​the liquid pump is greater than the pressure forcing the liquid into the liquid pumping area.

[0010] Since the manipulator head comprises both the liquid cell and the liquid pump, a more compact construction can be achieved, whereby a smaller distance between the liquid cell outlet of the liquid cell and the liquid pumping area of ​​the liquid pump can be achieved. This reduces the forces acting against the liquid, which prevent the liquid from extending into the liquid pumping area of ​​the liquid pump. In particular, if the distance between the liquid cell outlet of the liquid cell and the liquid pumping area is shorter, and thus the liquid line between the liquid cell outlet and the liquid pumping area is also shorter, the pressure loss along the liquid line between the liquid cell outlet of the liquid cell and the liquid pumping area of ​​the liquid pump can be reduced. This pressure loss is caused in particular by friction forces between the liquid and the liquid line. The pressure loss along the liquid line can be reduced so that the pumping of the liquid by the liquid pump acts on the liquid at an absolute pressure of less than 600 mbar, for example an absolute pressure of less than 400 mbar, for example an absolute pressure of less than 100 mbar, in particular 0.1 mbar to 100 mbar, for example 10 mbar to 100 mbar. This allows the liquid to be pumped and thus exchanged during operation of the manipulator head and in particular the liquid cell at absolute pressures below 600 mbar, for example below 100 mbar, without the need to create a higher pressure around the manipulator head in order to allow pumping. This also allows the liquid cell to be emptied. Since it is not necessary to release the negative pressure in order to exchange the liquid, the ingress of dirt into the surroundings of the manipulator head, in particular into the liquid cell, can be prevented or at least reduced. This allows an improved operation of the manipulator head. For example, the liquid can be pumped and, for example, exchanged without a pressure increase during operation of the manipulator head, in particular the liquid cell in vapor pressure equilibrium of the liquid. Furthermore, since it is possible to add or remove liquid to or from the liquid cell at the desired operating pressure, measurements at different liquid levels in the liquid cell are possible.For example, when the manipulator head is used to analyze a sample in a negative pressure system with an illumination system and a detector system, the sample can be analyzed in a non-wet state, a wet state, and with a liquid film of different thicknesses on the surface of the sample without having to change the location on the sample to be measured.

[0011] The distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump is selected so that the liquid extends at least into the liquid pumping region when a negative pressure of less than 600 mbar, in particular a negative pressure of 100 mbar or less, occurs in the internal space of the liquid cell, so that the liquid can be pumped for different liquids and different operating parameters of the liquid cell.

[0012] Extending into the liquid pumping region of the liquid pump, so that the liquid pump can pump the liquid, is understood to mean that the liquid extends into the liquid pump to such an extent that the pumping element can act to pump the liquid. For example, the pumping element may be a compression element, such as a roller or a sliding shoe of a peristaltic pump. In this case, the liquid must extend into the liquid pump to such an extent that the liquid can be pumped by compressing the liquid line of the liquid pump with the compression element and then moving the compression element while compressing the liquid line. In this case, the liquid pumping region starts behind the compression position of the compression element and the liquid must extend in the liquid line beyond the compression position of the compression member in order for the liquid pump to be able to pump the liquid.

[0013] With the negative pressure occurring in the internal space of the liquid cell, the pressure acting on the liquid may basically be so low that the pressure loss along the liquid line between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump is greater than the pressure pushing the liquid in the direction of the liquid pumping region. In this case, the section from the liquid cell outlet to the liquid pumping region cannot be overcome by the liquid, so that the liquid does not reach the liquid pumping region or at least does not extend into the liquid pump to such an extent that the liquid pump can pump the liquid. In this case, the liquid cannot be pumped out of the liquid cell to empty it. In other words, in this case, the pressure generated by a liquid column of several centimeters, i.e. a hydrostatic pressure of several millibars and possibly a dynamic pressure due to the additional pumping of the liquid into the internal space, may be less than the pressure loss along the liquid line. If the liquid line is shortened, from a certain length, the pressure loss is less than the pressure acting on the liquid, so that the liquid can extend to the liquid pumping region and pump the liquid.

[0014] The pressure loss Δp between a first position in the liquid line, for example the liquid line inlet, and a second position in the liquid line, for example the compression position of the compression element 12 For example, based on the Darcy-Weisbach equation,

number

number

[0015] Total pressure acting in the liquid pipeline p tot For steady flow of a viscosityless, incompressible fluid, the Bernoulli pressure equation p tot =p dyn +p stat Using the dynamic pressure p dyn = 2u + 2, the operating pressure p and the hydrostatic pressure p of the fluid column g = Static pressure p, which is composed of ρ g h stat =p+ρ·g·h, where g is the acceleration of gravity and h is the height of the liquid column. Furthermore, other pressures, e.g. due to the compressibility of the liquid, the viscosity of the liquid and / or the capillarity of the liquid line, can be taken into account in the Bernoulli pressure equation. Then, using the Bernoulli pressure equation and the Darcy-Weisbach equation, the maximum length of the liquid line at which the total pressure is greater than the pressure loss can be estimated, and the spacing between the liquid cell outlet and the liquid pumping region of the liquid pump can be selected correspondingly so that the liquid extends into the liquid pumping region of the liquid pump and the liquid can be pumped.

[0016] A person skilled in the art can also determine, for example, by simple experiments, the distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump, at which the liquid extends into the liquid pumping region at a pressure below 600 mbar. For this, for example, it can be tried for liquid lines having the same liquid line inner diameter and different lengths, which liquid lines extend into the liquid pumping region of the liquid pump and thus can be pumped. This makes it possible to take into account the parameters of the negative pressure system in which the manipulator head is arranged, such as, for example, the viscosity of the liquid, the diameter of the liquid cell outlet, the liquid line inner diameter, the diameter of the liquid pumping region and other parameters.

[0017] The spacing between the liquid cell outlet and the liquid pumping region may be vertical, horizontal, or a combination of vertical and horizontal spacing. By providing a vertical spacing between the liquid cell outlet and the liquid pumping region, an additional gravitational force acts on the liquid, which can generate an additional pressure to push the liquid to the liquid pumping region. This makes it possible, for example, to act against possible adhesion forces. In other words, the vertical spacing causes a gravitational force on the liquid, which causes a positive force to act on the liquid to push it to the liquid pumping region even in the case of absolute pressures below 600 mbar, which can overcome the adhesion forces of the liquid lines.

[0018] The liquid line may be made of a material that is not compressible at atmospheric pressure. A material is considered to be incompressible if the internal diameter of the liquid line shrinks by less than 5% when atmospheric pressure acts on the liquid line from the outside when a negative pressure, for example less than 600 mbar, in particular less than 100 mbar, prevails in the liquid line. The material of the liquid line is preferably vacuum-compatible, chemically resistant and inert. This material may, for example, comprise or be steel or a plastic, for example polyetheretherketone (PEEK) or polytetrafluoroethylene (PTFE). The liquid line may, for example, be a steel line, the inner wall of which is coated with a plastic such as PEEK or PTFE. Alternatively, the liquid line may be made of an elastic material, which allows the liquid line to be pinched. The liquid line may, for example, be a PEEK hose.

[0019] The liquid line may be configured such that it does not collapse when atmospheric pressure acts on it from the outside, or that its inner diameter reduces by less than 5% when an absolute pressure of, for example, less than 600 mbar, in particular less than 100 mbar, prevails in the liquid line, for example. For this purpose, the inner diameter of the liquid line, the outer diameter of the liquid line, the wall thickness of the liquid line and the material properties of the liquid line may be correspondingly adjusted to one another.

[0020] The spacing between the liquid cell outlet and the liquid pumping region may be, for example, 0.1 mm to 200 mm, such as 0.1 mm to 100 mm or 1 mm to 40 mm. The liquid conduit may correspondingly have a length, for example, of 0.1 mm to 200 mm, such as 0.1 mm to 100 mm or 1 mm to 40 mm.

[0021] The liquid conduit may have a constant liquid conduit inner diameter, for example 0.5 mm to 4 mm. This allows for the provision of thin liquid conduits, which allows for a compact construction of the manipulator head. Furthermore, a reduced volume for the lumen surrounded by the liquid conduit can be achieved. The liquid conduit inner diameter may be for example 1 mm to 4 mm, for example 2 mm or 2.8 mm. A compact construction is not possible in the case of a large liquid conduit inner diameter, since a larger liquid conduit inner diameter leads to a larger liquid conduit outer diameter. A smaller liquid conduit inner diameter may cause capillary action. The liquid conduit inner diameter may be selected such that the forces caused by capillary action are smaller than other forces acting on the liquid. This allows for a reduction in adhesion forces in the liquid conduit.

[0022] The manipulator head may be an assembly of a liquid cell and a liquid pump connected to each other, the liquid cell and the liquid pump together being arranged in a negative pressure housing or attached to a manipulator or both being arranged in a negative pressure housing and attached to a manipulator. In particular, the manipulator head may be a manipulator head for a manipulator, i.e. the manipulator head may be suitable for being connected to a manipulator, in particular it may be attached to a manipulator.

[0023] The manipulator head may have a housing in which the liquid cell and the liquid pump are arranged, or alternatively, the liquid cell and the liquid pump may be arranged separately in two housings connected to each other.

[0024] The manipulator head may have an attachment device, which is configured to be attached to the manipulator. The attachment device may, for example, have a fastener. The attachment device may be only one surface with an attachment means. For example, the attachment device may be the bottom of the manipulator head with a threaded hole, which may be placed on one surface of the manipulator, and into which a threaded hole in the manipulator a screw capable of being attached can be introduced, by which the manipulator head can be connected to the manipulator.

[0025] The liquid pump can be connected directly to the liquid cell outlet, so that the distance between the liquid cell outlet and the liquid pumping area has a very short length, for example less than 1 mm, in particular 0.5 mm or less.

[0026] The liquid conduit does not have to terminate at the liquid pumping region of the liquid pump, but may extend beyond the liquid pumping region of the liquid pump, for example, especially if the liquid pump is a peristaltic pump and the liquid conduit extends through the peristaltic pump.

[0027] The liquid cell outlet and the liquid pumping region may be arranged relative to each other such that, when a negative pressure of less than 600 mbar, in particular less than 100 mbar, is generated in the internal space of the liquid cell, the liquid can extend at least into the liquid pumping region by the action of gravity alone, thereby enabling the liquid pump to pump the liquid.

[0028] The liquid cell outlet may be arranged in a bottom region of the liquid cell, in particular at the deepest point of the internal space of the liquid cell. The liquid cell outlet of the liquid cell may be arranged at a vertical distance from the liquid pumping region of the liquid pump, the vertical distance being selected such that, in the event of an absolute pressure of less than 600 mbar occurring in the internal space of the liquid cell, for example less than 400 mbar, in particular less than or equal to 100 mbar, the liquid extends at least to the liquid pumping region of the liquid pump, so that the liquid pump can pump the liquid.

[0029] The bottom region may for example include the bottom of the liquid cell and / or a part of the wall of the liquid cell, in particular the part of the wall that is in contact with the bottom. The liquid cell outlet may be located at the deepest point of the interior space of the liquid cell. For example, the liquid cell outlet may be located on the wall of the liquid cell such that the deepest point of the liquid cell outlet forms the deepest point of the interior space of the liquid cell.

[0030] The liquid cell outlet of the liquid cell is arranged in the bottom region of the liquid cell, in particular at the deepest point of the internal space, so that the liquid can flow from the internal space to the liquid cell outlet. The liquid cell outlet of the liquid cell is arranged at a vertical distance from the liquid pumping region of the liquid pump, so that gravity acts on the liquid between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump. Gravity acts in the opposite direction to the forces preventing the liquid from entering the liquid pumping region of the liquid pump. Furthermore, the vertical distance is selected such that the liquid extends at least into the liquid pumping region of the liquid pump at an absolute pressure of less than 600 mbar, in particular less than or equal to 100 mbar, in the internal space of the liquid cell, so that the liquid pump can pump the liquid. In other words, the vertical distance is selected such that gravity is stronger than all opposing forces preventing the liquid from extending into the liquid pumping region.

[0031] The vertical spacing may for example be 1 mm to 200 mm, such as 1 mm to 40 mm, in particular 5 mm to 20 mm, for example 12 mm.

[0032] The bottom of the liquid cell may be inclined towards the liquid cell outlet. The inclination may be selected such that the liquid flows in the direction of the liquid cell outlet. This allows for an improved outflow of the liquid to the liquid cell outlet and thus from the liquid cell. The inclination angle of the inclination may be, for example, between 2° and 45°, or between 2° and 20°. The liquid cell outlet may be, for example, located on one side of the liquid cell or in the middle of the liquid cell.

[0033] The liquid pump may comprise a positive displacement pump, in particular a peristaltic pump, which allows for a simple construction of the manipulator head.

[0034] The peristaltic pump may have a housing surrounding the liquid line. The liquid line may be arranged in a wall of the housing. The housing may have a rotor and one or more compression elements, such as rollers or sliding shoes. The rotor may be coupled to this compression element and may drive this compression element. The rollers or sliding shoes may be arranged such that they can compress or pinch the respective sections of the liquid line during rotation of the rotor, so that the liquid can be pumped. The rollers may have, for example, lubricant-free hybrid ball bearings. If the liquid pump is provided in the form of a peristaltic pump, the liquid line is preferably a hose that can be pinched by the rollers or sliding shoes of the peristaltic pump. Providing a liquid pump in the form of a peristaltic pump allows a simple and robust construction, in which components in contact with the liquid, in particular liquid lines in the form of hoses, can be easily replaced.

[0035] The liquid pump may be or include, for example, a diaphragm pump, a piezoelectric pump, an electroosmotic pump or another type of positive displacement pump. The liquid pump may be or include a microfluidic pump.

[0036] The liquid pump may have an inlet pressure of 0 mbar. The liquid pump may be made of one or more heat-resistant materials, for example heat-resistant up to more than 150° C. or up to more than 300° C., so that the liquid pump can be heated.

[0037] The liquid pump may be made from ultra-high vacuum compatible (UHV compatible) materials. These materials have a melting point of 10° C. at 150° C., for example. -10 mbar, 10 at 130°C-8 It may have a very low vapor pressure, down to the order of less than mbar. The material may be or include stainless steel, aluminum or PEEK, for example.

[0038] The liquid cell may be an electrochemical cell. The electrochemical cell may have a working electrode and a counter electrode. This allows the electrochemical cell to be operated at a negative pressure of up to 600 mbar and its properties and behavior to be investigated using a suitable analytical system. The working electrode may be used, for example, as the sample to be analyzed or measured. The liquid cell may have one or more further electrodes, for example a reference electrode.

[0039] The liquid may, for example, comprise a liquid electrolyte, for example a water-based electrolyte, or may be a liquid electrolyte, for example a water-based electrolyte. Alternatively or additionally, the liquid may, for example, comprise a water-based solution, an alcohol-based liquid, for example an alcohol, such as glycol or ethanol, or an oil, for example an engine oil, for example 5W40, or may be a water-based solution, an alcohol-based liquid, or an oil.

[0040] The working electrode may be arranged in the electrochemical cell at an inclination with respect to the liquid level. This inclination may be, for example, between 0.1° and 80°, in particular between 15° and 45°. The inclination may be selected such that a first part of the working electrode protrudes from the liquid during operation, a second part of the working electrode is wetted by the liquid, and a third part of the working electrode is located in the liquid. The working electrode may be arranged at a fixed inclination relative to the housing wall of the electrochemical cell, which results in a fixed inclination with respect to the liquid level when the liquid cell is filled with liquid. Alternatively, the working electrode may be arranged on a tilting device that allows the inclination angle of the working electrode relative to the housing wall of the electrochemical cell to be adjusted, which also allows the inclination angle with respect to the liquid level to be adjusted. Alternatively or additionally, the electrochemical cell may be tilted such that the working electrode is inclined with respect to the liquid level. The electrochemical cell may be tilted, for example, with a manipulator.

[0041] Since the working electrode can be arranged in the electrochemical cell at an angle to the liquid level, different measurements can be carried out with this working electrode, i.e. at the working electrode itself, at the working electrode when it is wetted by the liquid, and at the liquid itself, for which only little or no movement of the working electrode relative to the radiation spot or of the radiation spot relative to the working electrode is required, depending on the operation of the electrochemical cell.

[0042] The liquid cell may have a cover with an opening. The opening may be sized to ensure that the liquid in the liquid cell is fluidly connected to the surroundings of the manipulator head ... 2 ~10cm 2The opening may have an area of ​​0.1 mm to 0.5 mm. The opening may be, for example, oval, circular or rectangular. The cover makes it possible to prevent or at least reduce an unintended escape of liquid from the liquid cell to the surroundings of the manipulator head. The inner surface of the cover facing the liquid may be coated. For example, a coating made of PTFE or PEEK may be provided.

[0043] The inner wall of the liquid cell may be made of a plastic, such as PEEK. The inner wall of the liquid cell may be coated with or made of PTFE.

[0044] The manipulator head may have a temperature adjustment device. The temperature adjustment device may include one or more heaters and / or coolers. The temperature adjustment device may be arranged in or inside the liquid line, the liquid supply line, the liquid cell and / or the liquid pump. This allows the liquid to be thermoregulated, i.e. heated or cooled, thereby adjusting a desired temperature for the liquid at a defined position of the manipulator head. Different heaters and coolers may be provided at different positions of the manipulator head. This allows adjusting different temperatures for the liquid at different positions of the manipulator head.

[0045] The manipulator head may comprise a buffer cell. The buffer cell may for example serve as a liquid reservoir, in particular as an electrolyte reservoir. The buffer cell may for example be arranged below the liquid cell. The buffer cell may be configured to collect liquid that has flowed out of the liquid cell. For example, in order to collect liquid that has flowed out of the liquid cell, the buffer cell may be open towards the top and may have a larger bottom surface than the liquid cell. This allows for collecting liquid that flows out unintentionally.

[0046] The buffer cell may be configured to act as a vapor pressure buffer.

[0047] The temperature adjustment device may further be configured to adjust the temperature of the buffer cell. One or more heaters and / or coolers of the temperature adjustment device may be arranged, for example, at or in the buffer cell. This allows, for example, to heat the buffer cell. This allows, for example, to create a vapor pressure equilibrium between the electrolyte volume in the electrochemical cell and the electrolyte volume in the buffer cell, when the liquid cell is an electrochemical cell and the liquid is an electrolyte. This allows, for example, to keep the electrolyte level in the electrochemical cell constant. For this purpose, for example, the temperature of the buffer cell can be slowly or carefully changed, which allows for an equal vapor pressure equilibrium between the electrochemical cell and the buffer cell, when the electrochemical cell and the buffer cell are operated at negative pressure in a negative pressure housing.

[0048] The manipulator head may have one or more liquid reservoirs or may be connected to one or more liquid reservoirs. The liquid reservoir may be arranged, for example, in a hollow chamber of the negative pressure housing. This allows for pumping liquid from the liquid reservoir into the liquid cell. For example, a liquid pump or another pump may be used to pump liquid from the liquid reservoir into the liquid cell. The liquid reservoir may act as a vapor pressure buffer.

[0049] The manipulator head may have a spacing adjustment device configured to adjust a spacing between the liquid cell and the liquid pump. The spacing adjustment device may include or be a height adjustment device. The height adjustment device may be configured to adjust a vertical spacing between a bottom of the liquid cell and a liquid pumping region of the liquid pump.

[0050] Alternatively, the vertical spacing may be selected such that all liquid that is desired to be used under negative pressure during operation of the manipulator head extends at least to the liquid pumping region of the liquid pump, so that the liquid can be pumped by the liquid pump. This makes it possible to ensure that the liquid extends into the liquid pumping region of the liquid pump when an absolute pressure of less than 600 mbar, in particular less than or equal to 100 mbar, occurs in the inner space of the liquid cell during operation of the manipulator head. The spacing, in particular the vertical spacing, can therefore be adapted to other conditions or parameters of operation, such as the viscosity of the liquid and the inner diameter of the liquid line.

[0051] According to another aspect of the invention, a manipulator is provided. The manipulator has a manipulator inner space. The manipulator is configured to be airtightly connected to the negative pressure housing. In particular, a cavity enclosed by the negative pressure housing may be airtightly connected to the manipulator inner space. The manipulator further has a movable shaft with a distal end. The distal end is movable in the cavity of the negative pressure housing in a state where the manipulator is connected to the negative pressure housing. The distal end of the movable shaft has a manipulator head according to at least one of claims 1 to 6 or an embodiment of this manipulator head. Thus, in a state where the manipulator is connected to the negative pressure housing, the manipulator head is arranged in the cavity of the negative pressure housing. This allows the manipulator head to be moved in the negative pressure housing, whereby a liquid cell can for example be prepared in a first position and analyzed or a measurement performed in a second position. To this end, the movable shaft can move the manipulator head from a first position to a second position, for example underneath the analysis system.

[0052] At least a part of the movable shaft may be arranged in the manipulator inner space. The manipulator may have a housing surrounding the manipulator inner space. The housing may be, for example, a hollow cylinder. The manipulator inner space may be a lumen. The movable shaft may be arranged at least partially in the lumen. The movable shaft may have a proximal end. The proximal end of the shaft may be arranged outside the vacuum housing, for example in the lumen of the manipulator, when the manipulator is coupled to the vacuum housing. The proximal end of the shaft may form the proximal end of the manipulator and may be arranged outside the lumen of the manipulator. The housing of the manipulator may have one or more accesses into the lumen. Through the lumen, and in particular in the lumen of the shaft surrounded by the movable shaft, a conduit may be guided through the manipulator. This conduit may include, for example, an electrical line and / or a liquid line. The access may be provided, for example, at or near the proximal end of the shaft.

[0053] The manipulator may be configured such that the distal end of the shaft can be moved within the negative pressure housing and / or returned to the downstream side of the valve within the manipulator interior space, allowing a liquid cell with a sample located at the distal end of the shaft to be prepared at a first pressure and analyzed at a second pressure.

[0054] The movable shaft may additionally be rotatable, which makes it possible to tilt the manipulator head.

[0055] The shaft portion may have an outer diameter of, for example, 36 mm to 38 mm. The lumen through which the shaft portion is guided may have an inner lumen diameter of, for example, 38 mm to 40 mm.

[0056] In accordance with another aspect of the present invention, a negative pressure system is provided, the negative pressure system comprising: a vacuum housing for sealingly enclosing the first cavity under the negative pressure, a manipulator head according to at least one of claims 1 to 6 or a manipulator according to one embodiment of this manipulator head; It has.

[0057] The manipulator head may be arranged in a first cavity of the negative pressure housing. The negative pressure system may be configured to generate an absolute pressure of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar, in the first cavity. The negative pressure system may for example have one or more pumps for generating the negative pressure in the first cavity.

[0058] In accordance with another aspect of the present invention, a negative pressure system is provided, the negative pressure system comprising: a vacuum housing for sealingly enclosing the first cavity under the negative pressure, - a manipulator according to claim 7 or according to one embodiment of this manipulator; It has.

[0059] The manipulator may be hermetically connected to the negative pressure housing. The manipulator head may be arranged in a first cavity of the negative pressure housing. The negative pressure system may be configured to generate an absolute pressure of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar, in the first cavity. The negative pressure system may for example have one or more pumps for generating the negative pressure in the first cavity.

[0060] The negative pressure system according to claim 8 or 9 or an embodiment of this negative pressure system may comprise an illumination system and a detector system. The illumination system may be configured to illuminate the liquid cell with particles or radiation. The detector system may be configured to receive particles or radiation emitted from the liquid cell.

[0061] The illumination system may comprise a radiation source, for example a radiation source for electromagnetic radiation, such as X-rays, synchrotron radiation, deep ultra-violet (DUV) or light. The illumination system may additionally comprise a monochromator for spectrally separating certain wavelengths from the incident beam from the radiation source. Alternatively or additionally, the illumination system may comprise a particle source. This makes it possible to provide particles or radiation that can be used to irradiate the liquid cell.

[0062] The illumination system may be movable and / or tiltable, so that the illumination system can be brought close to the liquid cell or the sample located in the liquid cell in order to illuminate the liquid cell or the sample with particles or radiation. Alternatively or additionally, the detector system may be movable and / or tiltable, so that the detector system can be brought close to the liquid cell in order to receive particles or radiation emitted from the liquid cell. Alternatively or additionally, the liquid cell may also be movable and / or tiltable, for example by a manipulator. The manipulator allows the illumination system, the detector system and the liquid cell to be moved and tilted relative to each other so that measurements and / or analysis can be performed. For example, the manipulator can move and tilt the liquid cell relative to the illumination system and the detector system in the first cavity.

[0063] The detector system may be configured to analyze the particles or radiation emitted from the liquid cell. The detector system may be, for example, a photoelectron spectrometer. The detector system may comprise a front cap electrode, one or more electron lenses, one or more deflectors, an analyzer and / or a detector. The detector system may comprise, for example, a front cap electrode, an electron lens, an analyzer and a detector. The detector system may comprise one or more cavities connected to each other, which form an internal space of the detector system, through which the particles or radiation emitted from the liquid cell can be guided from the front cap electrode to the detector. Additionally, the detector system may comprise one or more deflectors to direct the particles or radiation to the input of the analyzer.

[0064] The front cap electrode may have a conical shape and may have an input aperture that may have a conical extension so that gas molecules entering the input aperture can quickly disperse behind the inlet aperture into the cavity surrounded by the front cap electrode, allowing for a quick decompression, which may increase the free path length for electrons downstream of the inlet aperture.

[0065] Different negative pressures may prevail in the interconnected cavities, which can be further reduced in the direction from the inlet opening to the detector. For this purpose, different pressure reduction stages may be provided, and the pressure can be reduced to different intensities in the cavities arranged one after the other, for example by means of pumps with different pressure strengths. This makes it possible to maintain a lower pressure in the detector system, for example, in the first cavity of the negative pressure housing, between 0.1 mbar and 100 mbar, for example at an absolute pressure of 25 mbar, and in the cavity surrounded by the front cap electrode, between 10 mbar and 20 mbar. -4 mbar~10 -2 mbar range, e.g. 10 -3 mbar absolute pressure, in the subsequent hollow chamber, 10 -6mbar~10 -4 mbar, e.g. 10( -5 ) mbar absolute pressure, and in the cavity before the detector, 10 -8 mbar~10 -5 mbar range, e.g. 10 -6 An absolute pressure of 1000 mbar can be maintained.

[0066] The analyzer may for example be or have a hemispherical energy analyzer. The detector may for example have an electron multiplier, a phosphor screen, a video camera, a CCD sensor (English: charge-coupled device) and / or a CMOS sensor (English: complementary metal-oxide-semiconductor). The detector may be configured as a DLD (English: delay line detector).

[0067] The inlet opening of the front cap electrode can be arranged, for example, above the liquid cell, in particular above an opening in the cover of the liquid cell. The front cap electrode can be introduced into the interior space of the liquid cell, for example through an opening in the cover of the liquid cell. This allows the inlet opening of the front cap electrode to be arranged directly above the working electrode used as the sample. The opening in the cover of the liquid cell can be configured to allow particles or radiation, for example X-rays, from the illumination system to enter the liquid cell and to allow radiation or particles, for example electrons, to escape from the liquid cell through the opening. The cover of the liquid cell allows the inner walls of the liquid cell to be protected from charging, for example during photoemission experiments, in particular if the liquid cell is made of PEEK or coated with PEEK.

[0068] A window transparent to electrons may be provided in the opening, which may be made, for example, of a single layer of membrane, for example a single layer of carbon, in other words graphene, which allows a pressure different from the pressure in the interior space of the liquid cell to be adjusted around the manipulator head in the negative pressure housing.

[0069] The negative pressure system may have a second cavity that is hermetically separated from the first cavity during operation. The first cavity may be configured for use in a different pressure range than the second cavity. This makes it possible, for example, to prepare a liquid cell for a measurement in the second cavity and to carry out the measurement in the first cavity.

[0070] The liquid is free of unwanted gases, such as oxygen (O 2 ), carbon monoxide (CO 2 ) or carbon dioxide (CO 2 ). The negative pressure system may be configured to degas the liquid, for example thermal degassing. This makes it possible to prevent or at least reduce unintentional degassing of the liquid in the liquid cell. The negative pressure system may be configured to perform, for example, pressure degassing, vacuum degassing, membrane degassing or chemical degassing. Preferably, the degassing is performed outside the first cavity. This makes it possible to prevent or at least reduce the ingress of dirt into the first cavity and in particular into the liquid cell.

[0071] The negative pressure system may have one or more liquid reservoirs for providing and / or storing liquid. The liquid reservoir may be arranged in the first hollow space or may be fluidly connected to the first hollow space. This may allow liquid exchange without the need to interrupt the negative pressure. This may prevent or at least reduce the ingress of dirt into the first hollow space, in particular into the liquid cell.

[0072] The negative pressure system may include a potentiostat, which may be connected to one or more electrodes of the electrochemical cell, thereby varying the electrical potential within the electrochemical cell.

[0073] The negative pressure system may comprise or be connected to a negative pressure pump for generating a negative pressure in the first cavity. The negative pressure pump may be configured to generate a negative pressure in the first cavity. The negative pressure pump may be configured to generate an absolute pressure of, for example, 0.1 mbar to 600 mbar, 0.1 mbar to 400 mbar or 1 mbar to 100 mbar, for example 20 mbar. This allows to generate different pressures in the negative pressure system close to the ambient pressure, in particular close to the atmospheric pressure, preferably close to the vapor pressure of the liquid used. The negative pressure pump may be, for example, a diaphragm pump.

[0074] The first cavity may be filled with an inert gas. For example, the remaining molecules of air in the first cavity may be replaced by inert gas molecules. The inert gas may for example comprise a noble gas, for example argon, or a mixture of noble gases, or may be a noble gas or a mixture of noble gases. The inert gas makes it possible to prevent chemical reactions between the inert gas and the liquid.

[0075] The vacuum housing may be made, for example, from special steel. The vacuum housing may have one or more shut-off valves for tightly separating the first cavity from the surroundings of the vacuum housing.

[0076] The first cavity is, for example, 0.0001 m 3 ~1m 3 volume, e.g. 0.001m 3 ~0.1m 3 In particular, it may have a volume of 50 liters.

[0077] The negative pressure system may have a temperature adjustment device. The temperature adjustment device may include one or more heaters and / or coolers. The temperature adjustment device may be arranged in or inside the liquid line, the movable shaft, the liquid supply line, the buffer cell, the liquid cell and / or the liquid pump. This allows the liquid to be thermostated, i.e. heated or cooled, thereby adjusting a desired temperature for the liquid at a defined position of the negative pressure system. Different heaters and coolers may be provided at different positions of the negative pressure system. This allows adjusting different temperatures for the liquid at different positions of the negative pressure system.

[0078] The temperature adjustment device may have a temperature controller configured to prevent boiling of the liquid. This temperature controller may be connected to one or more sensors for detecting different parameters of the liquid, such as pressure and temperature, as well as the surrounding environment of the liquid. This may make it possible to avoid boiling of the liquid, thereby preventing splashing of the liquid from the liquid cell and thus contamination of the manipulator head and the first cavity with the liquid. In particular, the temperature controller makes it possible to reduce the vapor pressure, thereby making it possible to operate the liquid cell at a lower pressure.

[0079] In accordance with another aspect of the present invention, a method of manufacturing a manipulator head is provided, the method comprising the steps of: - providing a liquid cell having a liquid cell outlet and an internal space configured for containing a liquid and configured for negative pressure; - providing a liquid pump having a liquid pumping region fluidly connected to an outlet of the liquid cell and configured to pump liquid from the liquid pumping region under conditions of negative pressure in the interior space of the liquid cell; - selecting a distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump such that, in the event of an absolute pressure of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar, in the internal space of the liquid cell, the liquid extends at least to the liquid pumping region of the liquid pump, so that the liquid pump is able to pump the liquid; It has.

[0080] The interior space of the liquid cell may be provided to be fluidly connected to the periphery of the manipulator head, for example by providing or providing the liquid cell with an opening to the periphery of the manipulator head.

[0081] The liquid cell may be gas-tightly connected to the liquid pump.

[0082] In another aspect, the present invention also includes a method of manufacturing a negative pressure system, the method including, in addition to the step of manufacturing a manipulator head, the steps of: - providing a vacuum housing for tightly enclosing the first cavity at vacuum pressure; - providing a manipulator head in the first hollow chamber; Contains:

[0083] The method of manufacturing the negative pressure system may include the step of providing a manipulator. Additionally or alternatively, the method of manufacturing the negative pressure system may include: - providing an illumination system configured to illuminate the liquid cell with particles or radiation; - providing a detector system configured to receive particles or radiation emitted from the liquid cell;

[0043]

[0084] According to another aspect of the invention, a method for operating a negative pressure system according to claim 10 or an embodiment of a negative pressure system based on the negative pressure system according to claim 10 is provided, the method comprising the steps of: - generating an absolute pressure in the interior space of the liquid cell of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar; - providing a liquid in a liquid cell; - pumping liquid from a liquid pumping region of the liquid pump using the liquid pump, thereby pumping said liquid from the liquid cell; - arranging the liquid cell, the illumination system and the detector system relative to one another such that the liquid cell can be illuminated with particles or radiation from the illumination system and the radiation or particles can be received by the detector system; - irradiating the liquid cell with particles or radiation from an irradiation system; - detecting radiation or particles emitted from the liquid cell in a detector system; It has.

[0085] The negative pressure in the internal space can be created, for example, by creating a negative pressure in the first cavity when the internal space of the liquid cell is fluidly connected to the first cavity.

[0086] The preparation of the liquid in the liquid cell and the pumping of the liquid from the liquid pumping region of the liquid pump can be performed without the need to release the negative pressure. This allows the liquid to be exchanged during operation of the negative pressure system. The liquid can be exchanged at a negative pressure, in particular at an absolute pressure of less than 600 mbar. The distance between the liquid cell outlet and the liquid pumping region can be selected, for example, such that the liquid extends in the first cavity at least to the liquid pumping region at an absolute pressure of less than 600 mbar, thereby allowing the liquid pump to pump the liquid.

[0087] Providing the liquid in the liquid cell and pumping the liquid from the liquid pumping region with the liquid pump can be performed, for example, continuously, allowing for continuous replacement of the liquid, for example a water-based electrolyte.

[0088] A method of operating a negative pressure system may include one or more of the following steps: - moving and / or tilting the liquid cell using a manipulator to position the liquid cell, the illumination system and the detector system relative to one another such that the liquid cell can be illuminated with particles or radiation from the illumination system and the radiation or particles can be received by the detector system; - providing liquid in a liquid cell during pumping of liquid from a liquid pumping region of the liquid pump; - providing liquid in the liquid cell and pumping the liquid from a liquid pumping region of the liquid pump such that a predetermined liquid level in the interior space of the liquid cell is maintained constant; - providing a liquid in the liquid cell and pumping the liquid from a liquid pumping region of the liquid pump so as to vary the liquid level in the interior space of the liquid cell; - tilting a working electrode of the electrochemical cell such that during operation a first portion of the working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located within the liquid; - providing a liquid in an electrochemical cell such that a first portion of a working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located within the liquid, and pumping the liquid from a liquid pumping region by a liquid pump; - irradiating a working electrode of the electrochemical cell with particles or radiation from an irradiation system such that during operation a first portion of the working electrode protruding from the liquid, a second portion of the working electrode wetted by the liquid, and a third portion of the working electrode located within the liquid are irradiated in succession. It has.

[0089] Preparing the liquid may be done in such a way that overheating of the liquid is avoided, for example by pumping at a limited pumping speed and / or by pumping at a predefined maximum pressure.

[0090] A method for operating a negative pressure system includes: - preparing a liquid in a liquid cell and pumping the liquid from a liquid pumping region of the liquid pump such that the liquid level in the liquid cell is continuously changed; - irradiating a working electrode of an electrochemical cell with particles or radiation of an irradiation system at a specific location of the working electrode while the liquid level in the liquid cell is continuously changed;

[0043]

[0091] The continuous change may have a periodicity, for example the liquid level may rise to a maximum liquid level, then fall to a maximum liquid level, then rise again to the maximum liquid level.

[0092] According to another aspect of the invention, the use of the negative pressure system according to claim 10 or an embodiment of a negative pressure system based on the negative pressure system according to claim 10 comprises the following steps: -Surface analysis, -Measurement of surface reactions, -Measurement of liquid-solid reactions, -Measurement of liquid-gas reactions, -Measurement of liquids, -Thin layer measurements -Detection of foreign objects in liquids, -Photoemission measurement, -Photoelectron spectroscopy measurements at near atmospheric pressure -X-ray photoelectron spectroscopy measurements near atmospheric pressure -electrochemical measurements, - Battery analysis, -Oxidation measurements, -electrolyte measurement, -electrode measurement, -Sample measurement through liquid -Quality control, -Corrosion measurements, - Catalytic measurements, - Pressure dependent measurements, - Measurement of biological samples, -potential difference measurement, -Measurement of supersaturated liquids It is prescribed for.

[0093] Furthermore, according to yet another aspect of the present invention, the use of the method according to claim 12 or 13 or any embodiment of the method for operating a negative pressure system according to claim 10 or an embodiment of a negative pressure system based on the negative pressure system of claim 10 may be -Surface analysis, -Measurement of surface reactions, -Measurement of liquid-solid reactions, -Measurement of liquid-gas reactions, -Measurement of liquids, -Thin layer measurements -Detection of foreign objects in liquids, -Photoemission measurement, -Photoelectron spectroscopy measurements at near atmospheric pressure -X-ray photoelectron spectroscopy measurements near atmospheric pressure -electrochemical measurements, - Battery analysis, -Oxidation measurements, -electrolyte measurement, -electrode measurement, -Sample measurement through liquid -Quality control, -Corrosion measurements, - Catalytic measurements, - Pressure dependent measurements, - Measurement of biological samples, -potential difference measurement, -Measurement of supersaturated liquids It is prescribed for.

[0094] According to another aspect of the invention there is provided a computer program product for operating a negative pressure system according to claim 10 or an embodiment of a negative pressure system based on the negative pressure system according to claim 10. The computer program product comprises computer program code means which, when the computer program product is executed on a processor, causes the processor to perform the method according to claim 12 or 13 or any embodiment of the method.

[0095] According to another aspect, a computer-readable medium having a computer program product stored thereon is provided.

[0096] The manipulator head according to claim 1, the manipulator according to claim 7, the negative pressure system according to claim 8, the negative pressure system according to claim 9, the method according to claim 11, the method according to claim 13, the use according to claim 14 and the use according to claim 15 may have similar and / or identical preferred embodiments, in particular as defined in the dependent claims.

[0097] Furthermore, preferred embodiments of the invention may also be any combination of the features of the dependent claims or the above-mentioned embodiments in conjunction with the corresponding independent claim.

[0098] This and other aspects of the invention will now be described in more detail with reference to the embodiments illustrated in the drawings. [Brief description of the drawings]

[0099] [Figure 1] FIG. 2 is an exemplary schematic diagram showing a first embodiment of a negative pressure system in the form of a photoelectron spectroscopy system, with a manipulator head attached to a manipulator, according to a first embodiment with an electrochemical cell. [Diagram 2] FIG. 11 is a schematic diagram exemplarily illustrating a manipulator head according to a second embodiment. [Diagram 3] FIG. 2 is a schematic diagram exemplarily illustrating a second embodiment of a negative pressure system in the form of a photoelectron spectroscopy system, with a manipulator head according to a third embodiment mounted within a negative pressure housing. [Figure 4] FIG. 13 is a schematic diagram exemplarily illustrating a manipulator head according to a fourth embodiment. [Diagram 5] 1 is an exemplary flow chart illustrating one embodiment of a method for operating a negative pressure system. [Figure 6] 1 is an exemplary flow chart illustrating one embodiment of a method for manufacturing a manipulator head.

[0100] Description of the embodiment The embodiment of the manipulator head and the negative pressure system with the manipulator head as well as the method of operating the negative pressure system, which are described below with different embodiments, make it possible to pump and discharge the liquid itself at absolute operating pressures of less than 600 mbar, for example less than 400 mbar, in particular less than or equal to 100 mbar, preferably resulting in absolute operating pressures in the range of 0.1 mbar to 100 mbar, for example 10 mbar to 100 mbar. Thus, if necessary, the liquid cell can be emptied and the liquid in the liquid cell can be replaced without increasing the operating pressure. Furthermore, the liquid level can be changed without changing the operating pressure in the liquid cell. This makes it possible to carry out measurements at defined points of solid samples with different degrees of wetting by the liquid. Furthermore, for example, the liquid can be replaced continuously without changing the liquid level. This makes it possible, for example, to change the liquid outside the liquid cell, introduce the changed liquid into the liquid cell and measure the change in the liquid. Furthermore, it is possible to carry out longer measurements if the liquid is consumed during the measurement, since the liquid can be refilled during the measurement without changing the measurement conditions.

[0101] 1 shows, diagrammatically and exemplarily, a first embodiment of a negative pressure system in the form of a photoelectron spectroscopy (PES) system 100. The PES system 100 can be used, for example, to carry out measurements on a sample, for example a working electrode and a liquid in the form of a water-based electrolyte, at pressures close to ambient pressure, in particular at pressures between 0.1 mbar and 100 mbar absolute. Here, radiation is incident on the sample and on the liquid, and photoelectrons generated by the radiation are detected.

[0102] The PES system 100 comprises a manipulator head 10, a vacuum pump 50, a manipulator 60, a negative pressure housing 70 in the form of a vacuum chamber, an illumination system 80 in the form of a monochromated aluminum (Al) X-ray source and a detector system 90. Instead of an aluminum X-ray source, another X-ray source can also be used, for example a silver (Ag) or chromium (Cr) X-ray source or an X-ray source providing multiple wavelengths.

[0103] The manipulator head 10 is designed for use in a negative pressure housing 70, for example in the range of 0.1 mbar to 600 mbar. For this purpose, materials that are particularly suitable for such pressures are used to manufacture the manipulator head.

[0104] In this embodiment, the manipulator head 10 includes a liquid cell 12 in the form of an electrochemical cell and a liquid pump 14 in the form of a peristaltic pump (not shown in detail). Alternatively, other types of liquid pumps can be used, in particular other types of positive displacement pumps. Multiple liquid pumps may be provided.

[0105] The liquid cell 12 has an internal space 16 formed for negative pressure, the internal space 16 being adapted to contain a liquid 18 in the form of a water-based electrolyte. The internal space 16 is fluidly connected to the surroundings of the manipulator head 10 via an opening 19. The liquid cell 12 has three electrodes 13, 15 and 17 in this embodiment, namely the working electrode 13, the counter electrode 15 and the reference electrode 17. In other embodiments, a different number of electrodes may be provided, for example two or four electrodes. The liquid 18 can be introduced into the liquid cell 12 via a liquid cell inlet 20 and can be led out of the liquid cell 12 again via a liquid cell outlet 22. The liquid cell outlet 22 is arranged in this embodiment at the deepest point of the internal space 16 of the liquid cell 12, i.e. at the deepest point of the bottom 24 of the liquid cell 12. In other embodiments, the liquid cell outlet can also be arranged, for example, in another bottom region of the liquid cell, for example in contact with the bottom of the liquid cell wall. Furthermore, in this embodiment, the bottom 24 of the liquid cell 12 is inclined with a 10° inclination angle towards the liquid cell outlet 16. In other embodiments, the bottom may be formed without inclination or with a different inclination, for example with an inclination angle of 2°-20° towards the liquid cell outlet, so that the liquid flows in the direction of the liquid cell outlet and thus flows better out of the liquid cell.

[0106] The liquid pump 14 has a liquid pumping region 26 fluidly connected to the liquid cell outlet 22. For this purpose, the liquid cell outlet 22 is connected to the liquid pumping region 26 via a liquid line 28 in the form of a hose made of PEEK. The liquid pump 14 is configured to pump the liquid 18 from the liquid pumping region 26 under negative pressure in the interior space 16 of the liquid cell 12. In this embodiment, the liquid line 28 extends through the liquid pump 14 into a liquid reservoir 30, in which the pumped out liquid 32 can be stored. For better visibility, the liquid line 28 is only partially shown in the liquid pump 14. The liquid pump 14 has a roller (not shown) which can press against the liquid line 28 in the liquid pump 14, so that by moving the roller the liquid 18 can be pumped through the liquid line 28 in a piecewise manner. The roller can only press against the liquid line from a predefined pressing position, which in this case represents the beginning of the liquid pumping region 26.

[0107] The distance d between the liquid cell outlet 22 of the liquid cell 12 and the liquid pumping region 26 of the liquid pump 14 is selected so that, under an absolute pressure in the range of 0.1 mbar to 100 mbar in the interior space 16 of the liquid cell 12, the liquid 18 extends at least into the liquid pumping region 26, so that the liquid pump 14 can pump the liquid 18. In other words, the goal is to shorten the distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump so that the pressure loss is smaller than the pressure difference between the liquid cell outlet and the liquid pumping region. In this embodiment, the distance d is a vertical distance. In another embodiment, the distance may be composed of a vertical distance and a horizontal distance. In another embodiment, the spacing between the liquid cell outlet and the liquid pumping region may be selected such that the liquid extends at least to the liquid pumping region when an absolute pressure of less than 600 mbar, for example less than 400 mbar, in particular less than 100 mbar, is generated, thereby enabling the liquid pump to pump the liquid.

[0108] In this embodiment, the liquid outlet 22 and the liquid conduit 28 each have a constant inner diameter of 2.8 mm. In other embodiments, these inner diameters may be different from each other, for example between 1 mm and 4 mm, for example 2 mm. The inner diameter of the liquid conduit may in other embodiments be adapted to the application, in particular the viscosity of the liquid.

[0109] The distance d between the liquid cell outlet 22 and the liquid pumping region 26 is 12 mm in this embodiment. In this case, the length of the liquid line section between the liquid cell outlet 22 and the liquid pumping region 26 is also 12 mm. In other embodiments, this distance may be, for example, between 1 mm and 200 mm.

[0110] The vacuum pump 50 can pump gas out of the negative pressure housing 70, thereby generating a negative pressure in the first hollow chamber 72 of the negative pressure housing 70. The negative pressure in this case is an absolute pressure between 0.1 mbar and 100 mbar, for example 0.5 mbar, 1 mbar or 2 mbar. In alternative embodiments, the negative pressure may be, for example, less than 600 mbar, less than 400 mbar or less than or equal to 100 mbar.

[0111] The manipulator 60 has a manipulator interior space 62 and a movable shaft 64. The shaft 64 is also rotatable. The manipulator 60 is airtightly connected to a negative pressure housing 70. The movable shaft 64 has a distal end 65 and a proximal end 66. The distal end 65 is arranged in a first hollow chamber 72 of the negative pressure housing 70, and the proximal end 66 is located outside the negative pressure housing 70. A liquid supply line 67 from a liquid reservoir 69 extends through a lumen 63 extending through the movable shaft 64. A supply liquid 68 that can be introduced into the liquid cell 12 is stored in the liquid reservoir 69. For this purpose, the liquid supply line 67 is connected to the liquid cell 12 via the liquid cell inlet 20. The manipulator head 10 is attached to the distal end 65 of the movable shaft 64 of the manipulator 60. When the manipulator 60 is connected to the negative pressure housing 70, the movable shaft 64 is movable and tiltable within the first hollow chamber 72 of the negative pressure housing 70, so that the manipulator head 10 is positioned within the first hollow chamber 72 of the negative pressure housing 70.

[0112] The irradiation system 80 includes an X-ray source 82. In the X-ray source 82, an electron gun accelerates electrons towards an Al anode (not shown). X-rays are generated by the electrons colliding with the Al anode and are monochromatized using a monochromator 84. The monochromatized X-rays X exit the monochromator outlet 86 and are incident on the working electrode 13 to excite photoelectrons p. In another embodiment, the irradiation system can generate other radiation or particles and irradiate the liquid cell with the radiation or particles.

[0113] The photoelectrons p are analyzed in a detector system 90. To this end, the detector system 90 includes a front cap electrode 92, a lens system 94, a hemispherical energy analyzer 96 and a detector 98.

[0114] The front cap electrode 92 has a shortest possible distance, for example in the range of 0.2 mm to 0.5 mm, from the working electrode 13 of the liquid cell 12 so that as many photoelectrons p as possible emitted from the working electrode 13 of the liquid cell 12 can enter the inlet opening of the front cap electrode 92 of the lens system 94. In this embodiment, the front cap electrode has a conical shape. This allows a rapid reduction in pressure inside the lens system 94. Additionally, a further vacuum pump (not shown) is provided which reduces the pressure in the cavities located one behind the other of the lens system 94. This makes it possible to maintain an operating pressure of, for example, 0.1 mbar to 100 mbar in the first cavity 72, while a pressure of, for example, 10 mbar is maintained in the cavity upstream of the detector 98. -8 mbar~10 -5 mbar, e.g. 10 -6 Only absolute pressures of mbar prevail, which makes it possible to reduce the loss of photoelectrons due to collisions with gas molecules and thus to improve the quality of the signal.

[0115] The lens system 94 serves to transmit the photoelectrons p to a hemispherical energy analyzer 96 and to focus the photoelectrons p so that the hemispherical energy analyzer 96 can separate them according to their kinetic energy. To this end, the lens system 94 may include different electron optical lenses and / or deflectors (not shown). The photoelectrons p can then be detected by a detector 98. The detector 98 may be, for example, a CMOS detector. The impact positions of the photoelectrons measured by the detector 98 can then be assigned to corresponding kinetic energies, which allows the photoelectrons p to be analyzed.

[0116] In another embodiment, the detector system may be configured to receive and analyze other particles or radiation emitted from the liquid cell.

[0117] 2 shows a schematic and exemplary representation of a manipulator head 10' according to a second embodiment. The manipulator head 10' comprises a liquid cell 12 in the form of an electrochemical cell, a liquid pump 14 in the form of a peristaltic pump, a mounting device 34, a buffer cell 36 and a temperature control device 38. Components which are the same as in the other embodiment are provided with the same reference numbers.

[0118] The liquid cell 12 comprises a working electrode 13, a counter electrode 15 and a reference electrode 17. The working electrode 13 is arranged at an inclination with respect to the level of the liquid 18 in the electrochemical cell 12. The inclination is selected such that a first part 23 of the working electrode 13 protrudes from the liquid 18, a second part 23' of the working electrode 13 is wetted by the liquid 18 and a third part 23'' of the working electrode 13 is located in the liquid 18. In another embodiment, the relative inclination angle of the working electrode with respect to the liquid level can also be changed by a tilting device. In another embodiment, the entire liquid cell can be tilted, for example, such that the working electrode is inclined relative to the liquid level. The manipulator head, and thus also the liquid cell, can be tilted, for example, by a manipulator, by rotating a movable shaft of the manipulator by a defined angle.

[0119] Furthermore, the liquid cell 12 has an opening 19 connecting the interior space 16 of the liquid cell 12 to the surroundings. The working electrode 13 is disposed below the opening 19 so that the detector system can be brought into close proximity to the working electrode 13 or vice versa.

[0120] The liquid cell 12 has a liquid cell inlet 20 for introducing the liquid 18 and a liquid cell outlet 22 for removing the liquid 18 from the liquid cell 12. In this embodiment, the bottom 24 is also inclined, so that the liquid 18 flows in the direction of the liquid cell outlet 22. In this embodiment, the liquid pump 14 is directly connected to the liquid cell outlet 22. In this case, the distance d' between the liquid cell outlet 22 and the liquid pumping region corresponds to the wall thickness of the housing part forming the liquid cell outlet 22 and the short liquid line region upstream of the compression point, where the liquid pumping region 26 starts. In this case, the distance d' is, for example, 1 mm.

[0121] The mounting device 34 can be attached to the manipulator. In this embodiment, the mounting device 34 has a threaded hole 35 into which a screw can be threaded to attach the manipulator head 10 to the shaft of the manipulator.

[0122] Since the buffer cell 36 is open upward, the liquid 18 that splashes downward from the liquid cell 12 can be collected in the buffer cell 36.

[0123] The temperature control device 38 is disposed between the liquid cell 12 and the buffer cell 36 and includes a heater and a cooler for controlling the temperature of the liquid cell 12 and the buffer cell 36 .

[0124] FIG. 3 shows, diagrammatically and exemplarily, a second embodiment of a negative pressure system in the form of a PES system 100″. The PES system 100″ is similar to the PES system 100 shown in FIG. 1. The same reference numerals as in the alternative embodiment are used for the same components and reference is made to the description of FIG. 1 to explain the function of these components.

[0125] The PES system 100 ″ includes a manipulator head 10 ″, a vacuum pump 50 , a negative pressure housing 70 in the form of a vacuum chamber, an illumination system 80 in the form of a monochromated Al-X-ray source, and a detector system 90 .

[0126] Unlike the PES system 100, the manipulator head 10'' is mounted in the vacuum housing 70 in the PES system 100'', and not at the distal end of the manipulator. That is to say, in this embodiment, the manipulator head 10'' is not movable together with the manipulator. In order to align the illumination system 80 and the detector system 90 towards the working electrode 13 of the liquid cell 12'' of the manipulator head 10'', the illumination system 80 and the detector system 90 must therefore be correspondingly moved or possibly tilted in this embodiment. For this purpose, corresponding actuators (not shown) are provided. Alternatively, for example, a number of deflectors may be provided, which can align radiation or particles from the illumination system towards the working electrode (not shown). Furthermore, in this embodiment, the first liquid reservoir 69 is also located in the vacuum housing 70, so that the liquid supply line 67 also extends completely into the first hollow space 72 of the vacuum housing 70.

[0127] The manipulator head 10'' includes a liquid cell 12'' and a liquid pump 14'' that are connected to each other via a liquid line 28''.

[0128] The liquid cell outlet 22'' of the liquid cell 12'' is arranged in the wall of the liquid cell 12'' in the bottom region. The distance d'' of the liquid cell outlet 22'' of the liquid cell 12'' to the liquid pumping region 26'' of the liquid pump 14'' is in this embodiment composed of horizontal distances d1 and d2 and a vertical distance h''. The vertical distance h'' allows an additional hydrostatic pressure to act due to the liquid column of the liquid 18. The distance d'' is selected so that the acting pressure is greater than the pressure loss between the liquid cell outlet 22'' and the liquid pumping region 26'', in particular along the liquid line 28'', so that the liquid 18 extends into the liquid pumping region 26'' and the liquid pump 14'' can pump the liquid 18.

[0129] FIG. 4 shows diagrammatically and exemplarily a manipulator head 10'' according to a fourth embodiment.

[0130] The manipulator head 10''' includes a liquid cell 12''' and a liquid pump 14'''. In this embodiment, the liquid cell 12''' and the liquid pump 14''' are disposed within a common housing.

[0131] The housing has an opening 19, which is separated from the surroundings of the manipulator head 10''', by a transparent window 40 in the form of a graphene layer. This makes it possible to prevent the liquid 18 from exiting through the opening 19. This also makes it possible to adjust different pressures around the manipulator head 10''' and in the internal space 16'''. For example, a higher pressure may prevail in the liquid cell 12''' than around the manipulator head 10'''. Alternatively, another transparent window may be provided, which is transparent to the radiation and particles entering from the irradiation device and exiting from the liquid cell 12'''. "Transparent" does not mean here that no losses occur in the transparent window, but that the transmission is relatively high, for example more than 90%. Furthermore, instead of one opening, multiple openings with multiple transparent windows may be provided, for example an opening for the radiation or particles entering the liquid cell and an opening for the particles or radiation exiting from the liquid cell. In this case, the transparent windows may be made of different materials, each transparent to the penetrating radiation or the penetrating particles.

[0132] The liquid cell 12''' includes a slanted working electrode 13 and a counter electrode 15. The liquid 18 is introduced into the interior space 16''' of the liquid cell 12''' through the liquid cell inlet 20 and into the liquid pumping region 26''' of the liquid pump 14''' through the liquid cell outlet 22'''. The slanted bottom 24 acts to direct the liquid 18 to the liquid cell outlet 22'''. In this case, the distance d'''' between the liquid cell outlet 22''' of the liquid cell 12''' and the liquid pumping region 26''' of the liquid pump 14''' is the horizontal distance. The distance d''' is selected so that the liquid 18 extends into the liquid pumping region 26''' and the liquid pump 14''' can pump the liquid 18.

[0133] In another embodiment, the liquid cell may be tilted in order to make the liquid flow towards the liquid cell outlet, which may then be located on the wall of the liquid cell, in particular without touching the bottom. Preferably, the liquid cell outlet is arranged on the wall in such a way that when the liquid cell is tilted, the liquid cell outlet is located at the deepest point of the internal space of the liquid cell, so that the liquid flows out of this internal space. In this case, the tilt may be selected in such a way that the working electrode is aligned towards the illumination and detector system and a measurement can be performed.

[0134] 5 shows an exemplary flow chart of one embodiment of a method 500 for operating a negative pressure system. For example, the negative pressure system shown in FIG. 1 or FIG. 3 may be operated according to this method.

[0135] In step 502, an absolute pressure of 0.1 mbar to 100 mbar, for example 25 mbar, is generated in the inner space of the liquid cell. For this purpose, a vacuum pump is used to pump the gas out of a first hollow chamber of a negative pressure housing, which is fluidly connected to the inner space of the liquid cell. In another embodiment, an absolute pressure of, for example, less than 600 mbar, less than 400 mbar or less than 100 mbar, for example 1 mbar to less than 600 mbar, 1 mbar to less than 400 mbar or 1 mbar to 100 mbar, can also be generated in the inner space of the liquid cell.

[0136] In step 504, liquid is prepared in the liquid cell by introducing liquid into the liquid cell via the liquid cell inlet, the liquid extending into a liquid pumping region of the liquid pump so that the liquid pump can pump the liquid to circulate the liquid or to empty the liquid cell.

[0137] In step 506, liquid is pumped by the liquid pump from a liquid pumping region of the liquid pump, thereby pumping the liquid out of the liquid cell. In this embodiment, liquid is simultaneously supplied to the liquid cell via the liquid cell inlet, so that a constant exchange of liquid can be achieved. In other words, in this embodiment, steps 504 and 506 are performed such that a defined liquid level in the internal space of the liquid cell is maintained constant.

[0138] In another embodiment, the liquid in the liquid cell can be arranged and pumped from a liquid pumping region of the liquid pump such that the liquid level in the inner space of the liquid cell varies, for example continuously and / or periodically, which allows measurements to be performed at different liquid levels at a given measurement point.

[0139] In an alternative embodiment, the liquid cell can be emptied, for example after a measurement, allowing the container to be filled with another liquid.

[0140] In step 508, the liquid cell, the illumination system and the detector system are positioned relative to one another such that the liquid cell can be irradiated with x-rays from the illumination system and photoelectrons can be received by the detector system. In other embodiments, other beams or particles may be provided by the illumination system and the detector system can detect other particles or radiation.

[0141] In the case of the PES system shown in Figure 1, the liquid cell can be moved and tilted correspondingly by the manipulator so that the illumination spot of the illumination system is directed at the location of the working electrode of the liquid cell to be measured and the entrance opening to the detector system is positioned above the illumination spot, thereby allowing photoelectrons to enter the detector system.

[0142] In another embodiment, such as the PES system shown in Figure 3, the illumination system and detector system can be moved and tilted so that the radiation spot of the illumination system is aimed at the location to be measured on the working electrode of the liquid cell and the entrance opening to the detector system is positioned over the radiation spot, thereby allowing photoelectrons to be incident on the detector system.

[0143] In step 510, the liquid cell or the location to be measured of the working electrode of the liquid cell is irradiated with X-rays from the irradiation system. This generates photoelectrons that are incident on the detector system. Different parameters of the irradiation system can be optimized to generate as many photoelectrons as possible that can be incident on the detector system.

[0144] In another embodiment, the liquid cell may be irradiated with another radiation or particle to generate the radiation or particle.

[0145] Instead of the working electrode, another electrode of the liquid cell can be irradiated, or the liquid or the working electrode wetted with the liquid can be irradiated. The working electrode can, for example, be tilted so that the liquid forms a meniscus on the surface of the working electrode, thereby allowing the working electrode measurement to be performed with a thin liquid film.

[0146] The working electrode may be tilted such that a first portion of the working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located in the liquid. The liquid may be prepared in the electrochemical cell such that, in operation, a first portion of the working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located in the liquid, and the liquid may be pumped from a liquid pumping region. In this case, for example, the working electrode may be irradiated with particles or radiation from an irradiation system such that the first portion of the working electrode protruding from the liquid, the second portion of the working electrode wetted by the liquid, and the third portion of the working electrode located in the liquid are irradiated in succession. For this purpose, a spot may be moved on the working electrode. Alternatively, the liquid may be pumped so that the liquid level is changed by raising the liquid level in the liquid cell, so that measurements can be performed in succession at the same measurement point on the working electrode with and without a liquid film.

[0147] Photoelectrons emitted from the liquid cell or from a location on the working electrode of the liquid cell to be measured are detected in a detector system in step 512. Different parameters of the detector system can be optimized to enable detection of the photoelectrons in the detector system.

[0148] In other embodiments, other particles or radiation may also be detected in the detector system.

[0149] The negative pressure systems 100 and 100' shown in Figures 1 and 3 and the method shown in Figure 5 may be used, for example, for surface analysis, surface reaction measurements, liquid-solid reaction measurements, liquid-gas reaction measurements, liquid measurements, thin film measurements, foreign object detection in liquids, photoemission measurements, photoelectron spectroscopy measurements at near atmospheric pressure, X-ray photoelectron spectroscopy measurements at near atmospheric pressure, electrochemical measurements, battery analysis, oxidation measurements, electrolyte measurements, electrode measurements, sample measurements through liquids, quality control, corrosion measurements, catalyst measurements, pressure dependent measurements, biological sample measurements, potentiometric measurements and / or measurements of supersaturated liquids.

[0150] 6 illustrates in an exemplary flow chart one embodiment of a method 600 for manufacturing a manipulator head. For example, one of the embodiments of manipulator heads 10, 10', 10'', 10''' shown in FIGS. 1, 2, 3 and 4 can be manufactured.

[0151] In step 602, a liquid cell in the form of an electrochemical cell is prepared. For this purpose, a housing is provided having four side walls and a bottom enclosing an internal space capable of containing a liquid, in particular a water-based electrolyte. Additionally, the housing has a cover with an opening. The housing is suitable for operation at negative pressure, in particular at an absolute pressure of less than 600 mbar, for example at or below 100 mbar. Optionally, a plurality of electrodes can be provided in the liquid cell, for example a working electrode, a reference electrode and a counter electrode.

[0152] The liquid cell further comprises a liquid cell inlet for introducing liquid into the liquid cell and a liquid cell outlet for withdrawing liquid from the liquid cell. In this embodiment, the liquid cell outlet is located at the bottom of the liquid cell, at the deepest point of the bottom, so that the liquid cell outlet can act as an outlet for liquid, similar to a tank outlet. This allows the liquid cell to be completely emptied. Optionally, the bottom is inclined towards the liquid cell outlet, for example at an inclination angle of 10°.

[0153] At absolute pressures below 600 mbar, the liquid will not automatically flow through the liquid line, depending on the inner diameter of the liquid line, the viscosity of the liquid and the length of the liquid line, so a liquid pump must be provided in addition to pump the liquid out.

[0154] In step 604, a liquid pump in the form of a peristaltic pump is provided. The liquid pump has a liquid pumping region. In this embodiment, the liquid pumping region is formed by a portion of a liquid conduit in the form of an elastic hose made of PEEK. In this embodiment, the liquid pumping region extends from a first compression point of the rollers of the liquid pump to a second point corresponding to the spacing between the rollers, so that when the rollers compress the hose, liquid is transported along the hose by the movement of the rollers. In other words, the liquid pump is capable of pumping liquid that extends within the liquid pumping region of the liquid pump.

[0155] In step 606, the spacing between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump is selected such that the liquid extends at least to the liquid pumping region at an absolute pressure of 1 mbar to 100 mbar in the interior space of the liquid cell, thereby enabling the liquid pump to pump the liquid. This ensures that the liquid can be pumped out of the liquid pumping region. In another embodiment, the spacing between the liquid cell outlet and the liquid pumping region can be selected such that the liquid extends at least to the liquid pumping region at an absolute pressure of less than 600 mbar, less than 400 mbar, or less than 100 mbar in the interior space of the liquid cell, thereby enabling the liquid pump to pump the liquid.

[0156] This distance may consist of a vertical distance and a horizontal distance. For example, the distance between the liquid cell outlet and the liquid pumping area can be shortened until the liquid pump can pump the liquid due to fixed other parameters, such as the liquid line inner diameter, the material of the liquid line, the desired absolute pressure in the inner space of the liquid cell and the viscosity of the liquid. For this purpose, for example, the length of the liquid line between the liquid cell outlet and the liquid pumping area can be reduced until the liquid can be pumped. This can be done experimentally on the one hand, but also calculated, for example, by simulation or on the basis of the Bernoulli equation.

[0157] The above description of the invention, in conjunction with the drawings, is used to exemplarily explain the features of the invention in the form of an embodiment. However, the features described in the embodiment are merely exemplary and should not be understood as limiting. In particular, the invention is not limited to the embodiments or combinations of features of the individual embodiments. For example, in one embodiment, the invention can also be operated together with another irradiation system, such as a synchronous radiation source or another detector system.

[0158] Further modifications and variations of the illustrated exemplary embodiments can be understood and effected by those skilled in the art upon reproduction of the claimed invention in light of the drawings, descriptions and claims.

[0159] The words "comprise", "have" and "include" do not exclude other elements, components or steps and the indefinite article "ein" does not exclude a plurality.

[0160] The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

[0161] Reference signs used in the claims should not be understood as limiting the features of the embodiments, but merely as illustrations for the features of the claims.

[0162] The invention relates to pumping liquid in a negative pressure system at negative pressure, in particular at pressures below 600 mbar absolute. For this purpose, a manipulator head is provided for use in a negative pressure housing under negative pressure. The manipulator head comprises a liquid cell and a liquid pump. The liquid cell has a liquid cell outlet and an internal space configured for receiving a liquid, configured for negative pressure. The liquid pump has a liquid pumping region fluidly connected to the liquid cell outlet and configured for pumping liquid from the liquid pumping region under conditions of negative pressure in the internal space of the liquid cell. The spacing between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump is selected such that under conditions of an absolute pressure of less than 600 mbar in the internal space of the liquid cell, the liquid extends at least into the liquid pumping region of the liquid pump, whereby the liquid pump is able to pump the liquid. This allows a compact construction for the negative pressure system, in which liquid can be circulated, and in particular emptied, at absolute pressures below 600 mbar.

Claims

1. a manipulator head (10; 10'; 10"; 10'") configured for use in a vacuum housing (70) under vacuum conditions; and a liquid cell (12; 12''; 12''') comprising a liquid cell outlet (22; 22''; 22''') and an internal space (16) configured for negative pressure, the internal space (16) being adapted to contain a liquid (18); a liquid pump (14; 14''; 14''') having a liquid pumping region (26; 26''; 26''') fluidly connected to the liquid cell outlet (22; 22''; 22''') and configured to pump the liquid (18) from the liquid pumping region (26; 26''; 26''') under conditions of negative pressure in the interior space (16) of the liquid cell (12; 12''; 12'''); and a manipulator (10;10';10'';10''') wherein the distance (d;d';d'';d''') between the liquid cell outlet (22;22'';22''') of the liquid cell (12;12'';12''') and the liquid pumping region (26;26'';26''') of the liquid pump (14;14'';14''') is selected such that the liquid (18) extends at least to the liquid pumping region (26;26'';26''') of the liquid pump (14;14'';14''') when an absolute pressure of less than 600 mbar, preferably less than 400 mbar, in particular less than or equal to 100 mbar is generated in the interior space (16) of the liquid cell (12;12'';12'''), thereby enabling the liquid pump (14;14'';14''') to pump the liquid (18).

2. The liquid cell outlet (22; 22'') is arranged in the bottom region of the liquid cell (12; 12''), in particular at the deepest point of the internal space (16) of the liquid cell (12; 12''), and the liquid cell outlet (22; 22'') of the liquid cell (12; 12'') is arranged at a vertical distance (d; d'; h'') from the liquid pumping region (26; 26'') of the liquid pump (14; 14''), and the vertical distance (d; d'; h'') is the distance between the liquid cell outlet (22; 22'') and the liquid pumping region (26; 26'') of the liquid cell (12; 12'').

2. The manipulator head (10; 10'; 10'') according to claim 1, wherein the liquid (18) extends at least into the liquid pumping region (26; 26'') of the liquid pump (14; 14'') when an absolute pressure of less than 600 mbar, preferably less than 400 mbar, in particular less than 100 mbar is generated in the internal space (16) of the cell (12; 12''), so that the liquid pump (14; 14'') is able to pump the liquid (18).

3. 3. A manipulator head (10; 10'; 10''; 10''') according to claim 1 or 2, wherein the bottom of the liquid cell (12; 12''; 12''') is inclined towards the liquid cell outlet (22; 22''; 22'''), the inclination being selected so that the liquid (18) flows in the direction of the liquid cell outlet (22; 22''; 22''').

4. Manipulator head (10; 10'; 10''; 10''') according to claim 1 or 2, characterized in that the liquid pump (14; 14''; 14''') comprises a positive displacement pump, in particular a peristaltic pump.

5. 3. The manipulator head (10; 10'; 10"; 10'") according to claim 1 or 2, wherein the liquid cell (12; 12"; 12'") is an electrochemical cell having a working electrode (13) and a counter electrode (15).

6. the working electrode (13) is disposed in the electrochemical cell (12; 12''; 12''') at an inclination relative to the liquid surface; a first portion (23) of the working electrode (13) protruding from the liquid (18) during operation; a second portion (23') of the working electrode (13) is wetted by the liquid (18); and A third portion (23'') of the working electrode (13) may be located within the liquid (18).

6. A manipulator head (10; 10'; 10''; 10''') according to claim 5, wherein the tilt is selected so that

7. 1. A manipulator (60) having a manipulator internal space (62), the manipulator (60) being configured to be airtightly connected to a negative pressure housing (70), the manipulator (60) having a movable shaft (64) with a distal end (65), the distal end (65) being movable within a hollow chamber (72) of the negative pressure housing (70) when the manipulator (60) is connected to the negative pressure housing (70), the distal end (65) of the movable shaft (64) having a manipulator head (10) according to claim 1 or 2, whereby the manipulator head (10) is disposed within the hollow chamber (72) of the negative pressure housing (70) when the manipulator (60) is connected to the negative pressure housing (70).

8. A negative pressure system (100; 100'') comprising: a negative pressure housing (70) for airtightly enclosing the first hollow chamber (72) when a negative pressure is generated; A manipulator head (10; 10'; 10''; 10''') according to claim 1 or 2, a negative pressure system (100; 100'') having

9. a negative pressure housing (70) for airtightly enclosing the first hollow chamber (72) when a negative pressure is generated; A manipulator (60) according to claim 7; A negative pressure system (100) comprising:

10. an illumination system (80) configured to illuminate the liquid cell (12; 12''; 12''') with particles or radiation (X); a detector system (90) configured to receive particles (p) or radiation emitted from said liquid cell (12; 12''; 12'''); 9. The negative pressure system (100; 100'') according to claim 8, comprising:

11. A method (600) for manufacturing a manipulator head, comprising: Providing (602) a liquid cell having a liquid cell outlet and an interior space configured for negative pressure, the interior space configured to contain a liquid; providing (604) a liquid pump having a liquid pumping region fluidly connected to the liquid cell outlet, the liquid pump being configured to pump the liquid from the liquid pumping region under conditions of negative pressure within the interior space of the liquid cell; selecting (606) a distance between the liquid cell outlet of the liquid cell and the liquid pumping region of the liquid pump such that the liquid extends at least to the liquid pumping region of the liquid pump when an absolute pressure of less than 600 mbar, preferably less than 400 mbar, in particular less than or equal to 100 mbar is generated in the interior space of the liquid cell, thereby allowing the liquid pump to pump the liquid; A method having the following.

12. 11. A method (500) for operating a negative pressure system according to claim 10, comprising: - generating (502) an absolute pressure in the interior space of the liquid cell of less than 600 mbar, preferably less than 400 mbar, in particular less than or equal to 100 mbar; Providing a liquid in the liquid cell (504); using a liquid pump to pump liquid from a liquid pumping region of the liquid pump, thereby pumping the liquid from the liquid cell (506); positioning (508) the liquid cell, the illumination system, and the detector system relative to one another such that the liquid cell can be illuminated with particles or radiation from the illumination system and the radiation or particles can be received by the detector system; irradiating the liquid cell with particles or radiation from the irradiation system (510); detecting radiation or particles emitted from the liquid cell with the detector system (512); A method comprising:

13. moving and / or tilting the liquid cell using the manipulator to position the liquid cell, the illumination system, and the detector system relative to one another so that the liquid cell can be irradiated with particles or radiation from the illumination system and the radiation or particles can be received by the detector system; providing the liquid in the liquid cell while pumping the liquid from the liquid pumping region of the liquid pump; providing a liquid in the liquid cell and pumping the liquid from the liquid pumping region of the liquid pump so that a defined liquid level in the interior space of the liquid cell is maintained constant; providing the liquid in the liquid cell and pumping the liquid from the liquid pumping region of the liquid pump so as to vary the liquid level within the interior space of the liquid cell; tilting the working electrode of the electrochemical cell such that during operation a first portion of the working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located within the liquid; providing the liquid in the electrochemical cell and pumping the liquid through the liquid pumping region of the liquid pump such that during operation, a first portion of the working electrode protrudes from the liquid, a second portion of the working electrode is wetted by the liquid, and a third portion of the working electrode is located within the liquid; irradiating the working electrode of the electrochemical cell with particles or radiation from the illumination system such that during operation, the first portion of the working electrode protruding from the liquid, the second portion of the working electrode wetted by the liquid, and the third portion of the working electrode located within the liquid are illuminated in succession; 13. The method of claim 12, further comprising one or more of the steps:

14. surface analysis, Measurement of surface reactions, Measurement of liquid-solid reactions, Measurement of liquid-gas reactions, liquid measurement, Thin layer measurements Detection of foreign objects in liquids, Photoemission measurement, Photoelectron spectroscopy measurements at near atmospheric pressure, X-ray photoelectron spectroscopy measurements at near atmospheric pressure, electrochemical measurements, Battery analysis, Oxidation measurements, electrolyte measurement, electrode measurement, Sample measurement through liquid quality control, Corrosion measurement, Catalyst measurement, Pressure-dependent measurements, Measurement of biological samples, Potentiometry, Measurement of supersaturated liquids Use of a negative pressure system (100; 100'') according to claim 10 for

15. surface analysis, Measurement of surface reactions, Measurement of liquid-solid reactions, Measurement of liquid-gas reactions, liquid measurement, Measurement of thin layers, Detection of foreign objects in liquids, Photoemission measurement, Photoelectron spectroscopy measurements at near atmospheric pressure, X-ray photoelectron spectroscopy measurements at near atmospheric pressure, electrochemical measurements, Battery analysis, Oxidation measurements, electrolyte measurement, electrode measurement, Sample measurement through liquid, quality control, Corrosion measurement, Catalyst measurement, Pressure-dependent measurements, Measurement of biological samples, Potentiometry, Measurement of supersaturated liquids Use of the method (500) of claim 12 for

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