Small-volume UHV ion trap package and method for forming it.

Abstract

Aspects of the present disclosure describe systems, methods, and structures that enable compact UHV ion trap systems that can operate above cryogenic temperatures. Ion trap systems according to the present disclosure are surface treated and sealed while maintained within a UHV environment, with dissimilar components joined via UHV seals, such as welded joints, compressible metal flanges, and UHV-compatible solder joints. This allows for extremely small volume systems by eliminating the need for cryogenic pumps.

Description

[Technical Field]

[0001] [Description of federally funded research] This invention was developed with government support under Federal License No. W911NF16-1-0082, granted by the United States Army Research Laboratory. The government reserves certain rights in this invention. [Cross-reference with related applications] This application is a continuation-in-part application of the concurrently pending U.S. Patent Application No. 16 / 913,932 (Agent No. 525-015US2), filed on June 26, 2020, which is a divisional application of the U.S. Patent Application No. 15 / 935,312 (Agent No. 525-015US1) (current U.S. Patent No. 10,755,913), filed on March 26, 2018, claiming the interests of the U.S. Provisional Application No. 62 / 533,927 (Agent No. DU5308PROV), filed on July 18, 2017. Each of these documents is incorporated herein by reference as if described in detail.

[0002] Furthermore, this application also claims the interests of U.S. Provisional Patent Application No. 63 / 049,842 (Agent Reference Number: DU7191PROV), filed on 9 July 2020, which is incorporated herein by reference as if it were described in detail herein.

[0003] This disclosure relates to quantum computing in general, and more specifically to an ion trap housing capable of supporting an ultra-high vacuum environment. [Background technology]

[0004] Systems using atomic ions are one of the primary physical platforms for practical quantum computers due to their long coherence time, complete connectivity between qubits, and high-fidelity gate operations. However, unlike solid-state based qubits, an integrated approach to extending trapped ion systems is not yet clear. Many novel ideas for designing complex trapped ion systems have been outlined in order to build practical trapped ion quantum computing systems.

[0005] Trapped ion experiments ultimately rely on the absence of collision events with background gas molecules, whether using conventional linear pole traps or microfabricated surface traps, to provide better qubit separation and reliable high-fidelity gates. Critically speaking, in the ultra-high vacuum (UHV) region (<1*10⁻¹⁰), -11 The pressure within the Torr (void) must be kept low enough to minimize ion-chain reordering events and ion loss from traps, thus reducing the background gas collision rate. Furthermore, quantum computing requires high-fidelity gates, which inevitably necessitates the excellent optics-mechanical robustness and stability of a scalable captured-ion quantum computer. To correctly utilize these transitions for qubit manipulation and readout, the optical frequency of the laser driving the near-resonant processes must be set to 10 10 The system should be stabilized within its range. In many cases, quantum logic gates are driven by Raman transitions where two far-detuned non-co-propagating beams with a precise frequency difference intersect at the ion's position. If the beam path and beam pointing of these Raman beams fluctuate, the optical phase and intensity at the ion will fluctuate, resulting in an imperfect gate. To avoid these problems, the ion trapping system and the optical elements used to deliver the laser beam must be stable against environmental noise such as temperature fluctuations, airflow, and mechanical vibrations. [Overview of the project]

Problems to be Solved by the Invention

[0006] In the prior art, by adopting a cryogenic system that suppresses the capacitance in the UHV operating region by using an extremely low temperature while maintaining the vacuum quality, the requirements for a scalable trapped-ion quantum computer have been met. However, cryogenic systems are large and expensive. In addition, an undesirable vibration is generated by a cryostat with a closed cycle.

[0007] A practical and compact trapped-ion system that does not require low-temperature operation is considered to advance the state-of-the-art technology.

Means for Solving the Problems

[0008] The present disclosure enables an extremely compact ion trap system that can operate at a non-extremely low temperature in an ultra-high vacuum and can have a system volume of 10 cubic centimeters (cc) or less.

[0009] By performing in-situ surface treatment and vacuum sealing of the ion trap enclosure while the ion trap enclosure of the ion trap system is held in an ultra-high vacuum (UHV) environment, an evolution from the prior art is achieved. As a result, the piece parts constituting the enclosure are joined using only UHV seals such as welded joints, vacuum flanges, and UHV-compatible solder seals. Further, embodiments according to the present disclosure do not include vacuum valves or pinch-off tubes that are large or known to have low reliability over time, which are commonly used in prior art ion trap enclosures. Further, by establishing a UHV environment before enclosing the ion trap in the enclosure, the need for a large and complex cryogenic vacuum system is avoided, resulting in a very low-volume ion trap system being possible.

[0010] An exemplary embodiment according to the present disclosure is about 2 cm 3This is an ion trap system that includes an enclosure that seals an ion trap in a high vacuum chamber having a volume of . The enclosure includes a chip carrier to which the ion trap is attached, a housing, and a lid, and all joints between the pieces of the enclosure are 10 -9 This is done using a UHV seal suitable for use in a UHV deposition system, while being placed in an environment with a pressure below Torr. Since the enclosure is sealed in an ultra-high vacuum to establish a baseline pressure, this ion trap system does not require a cryogenic cooling system. As a result, the chamber and the entire system can have a very small volume, and the ion trap can operate at temperatures above cryogenic. In some embodiments, a vacuum pump raises the pressure in the chamber to 10 -10 To keep Torr levels significantly lower, the enclosure is fluidly coupled to a vacuum pump before being sealed within the UHV environment.

[0011] In some embodiments, the enclosure includes one or more windows, which provide a viewport and optical access to a photoionization laser signal for loading ions into an ion trap and an optical access to a laser signal for ablating material to generate an atomic flux within the chamber, supply one or more laser signals used for initializing, manipulating and reading out a trapped ion qubit, and / or collecting scattered photons from the trapped ion qubit for imaging and qubit state detection.

[0012] Embodiments provided in this disclosure are ion trap systems comprising an ion trap disposed on a chip carrier and an enclosure enclosing the ion trap in a first chamber, wherein the enclosure comprises a plurality of piece parts including a chip carrier and a housing, the piece parts of the plurality of piece parts are joined by a plurality of seals consisting of UHV seals, and the first chamber is 10 -10 The pressure is less than Torr, and the first chamber is 10 cm 3An ion trap system having the following internal volume and having an operating temperature of -50°C or higher.

[0013] Another embodiment according to the present disclosure is an ion trap system including an ion trap disposed on a chip carrier, an enclosure including a plurality of piece parts including the chip carrier and a housing that encloses the ion trap in a first chamber, a plurality of seals consisting of UHV seals that join the piece parts of the plurality of piece parts, and an ion pump joined to the enclosure via a first UHV seal, wherein the first chamber has a pressure of 10 -10 Torr or less, the ion trap system does not use a cryosorption pump, and the ion trap system is configured to enable an operating temperature of -50°C or higher.

[0014] Yet another embodiment according to the present disclosure is a method of forming an ion trap system, the method including disposing an ion trap in a first environment having a first pressure of 10 -9 Torr or less, the ion trap being disposed within a chamber of an enclosure including a plurality of piece parts joined by a plurality of seals consisting of UHV seals, the chamber being open to the first environment, and forming a first UHV seal to isolate the chamber from the first environment while the ion trap and the enclosure are located within the first environment.

Brief Description of the Drawings

[0015] [Figure 1] It is a block diagram of an exemplary ion trap system according to the present disclosure. [Figure 2A] It is a schematic top view of an ion trap package according to an exemplary embodiment. [Figure 2B] It is a schematic cross-sectional view of an ion trap package according to an exemplary embodiment. [Figure 3]This figure shows the operation of a method suitable for forming an ion trap package, according to an exemplary embodiment. [Figure 4] This is a block diagram of the UHV assembly system as disclosed herein. [Figure 5] This figure shows the operation of the method for monitoring pressure within an ion trap system according to the present disclosure. [Figure 6A] This figure shows a simulation of the double well potential according to this disclosure. [Figure 6B] This figure plots the positions of trapped ions between wells in a double-well potential as a function of time, according to the present disclosure. [Figure 7] This figure shows the operation of another method for monitoring pressure within an ion trap system according to the present disclosure. [Figure 8A] This figure shows the first and second chain configurations used to estimate the collision energy of the 6-ion chain in Method 700. [Figure 8B] This figure shows a histogram of the time intervals between ion rearrangement events. [Modes for carrying out the invention]

[0016] The following is merely to explain the principles of this disclosure. Therefore, those skilled in the art will understand that they can devise various configurations that embody the principles of this disclosure, although not explicitly described or illustrated herein, and which fall within the spirit and scope of this disclosure.

[0017] Furthermore, all examples and conditional statements described herein are expressly intended solely for educational purposes to help readers understand the principles of this disclosure and the concepts introduced by the inventors (one or multiple) to advance the art, and should be construed as not being limited to such specifically described examples and conditions.

[0018] Furthermore, all descriptions herein describing the principles, aspects and embodiments of the present disclosure, as well as specific examples thereof, are intended to include both structural and functional equivalents. Such equivalents are also intended to include both currently known equivalents and future-developed equivalents, i.e., any developed elements that perform the same function regardless of structure.

[0019] Accordingly, for example, a person skilled in the art would understand that any block diagram in this specification represents a conceptual view of an exemplary circuit embodying the principles of the disclosure. Similarly, any flowchart, flow diagram, state transition diagram, and pseudocode, etc., would be understood to represent various processes that can be substantially represented in a computer-readable medium and that can be performed by such a computer or processor, whether or not such a computer or processor is explicitly indicated.

[0020] The functionality of various elements, including any functional block that can be labeled as a “processor” as shown in the diagram, can be provided through the use of dedicated hardware and, in relation to appropriate software, hardware capable of running software. When provided by a processor, these functions can be provided by a single dedicated processor, a single shared processor, or multiple individual processors, some of which may be shared. Furthermore, even when the terms “processor” or “controller” are explicitly used, they should not be interpreted as meaning solely hardware capable of running software, and may implicitly include digital signal processor (DSP) hardware, network processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), read-on memory (ROM), random-access memory (RAM), and non-volatile storage for storing software. Other conventional and / or custom hardware may also be included.

[0021] In this specification, a software module, or simply a module, which is implied to be software, may be represented as a combination of flowchart elements or other elements indicating the execution of process steps and / or text descriptions. Such modules may be executed by hardware, which may be explicitly or implicitly indicated.

[0022] Unless otherwise explicitly stated herein, all figures, including drawings, are not to scale.

[0023] For use in this specification, including in the attached claims, the following terms are defined: • A “UHV seal” is defined as a seal that is substantially impermeable to low molecular weight gases such as hydrogen and helium. The UHV seals according to this disclosure span at least 10 degrees across the barrier in which the UHV seal is located, such as a UHV environment in a chamber sealed using only the UHV seal. -10 The Torr pressure difference can be maintained. Examples of UHV seals suitable for use according to this disclosure include compressible metal flanges, UHV-compatible solders (e.g., indium, gold-tin, etc.), and welded joints. The definition of a UHV seal as presented herein explicitly excludes vacuum "pinch-off tubes," which are tubes used to evacuate a chamber and are sealed by mechanically clamping and / or soldering the tube after a vacuum pressure has been established in the chamber, as used in prior art ion trap systems. A “non-UHV seal” is defined as a seal that is not suitable for use in UHV deposition systems and / or is not substantially impermeable to low molecular weight gases such as hydrogen or helium. Examples of non-UHV seals include pinch-off tubes, compressible gaskets made of non-metallic materials, and non-UHV compliant solder seals.

[0024] Figure 1 is a block diagram of an exemplary ion trap system according to the present disclosure. The ion trap system 100 includes an ion trap package 102, an ion pump 104, an ablation laser 106, and an ionization laser 108.

[0025] The ion pump 104 is a compact, conventional ion pump fluidically coupled to the ion trap package 102.

[0026] The ablation laser 106 is a pulsed laser source suitable for supplying an ablation signal 114 to the material in the ion trap package 102 to generate atomic flux. As will be described later, optical access of the ablation signal 114 to the material to be ablated is made possible by including a window in the ion trap package 102. In the illustrated example, the ablation laser 106 is a Q-switched Nd:YAG pulsed laser with a wavelength of 1064 nm that supplies an 8 ns wide pulse with a pulse energy of 0.3 mJ, but other laser sources can also be used for the ablation laser 106.

[0027] The laser module 108 includes a conventional laser light source that provides a laser signal 116 with wavelengths suitable for ionization, Doppler cooling and detection of neutral atoms in the ion trap package 102, as well as optical re-pumping. In the illustrated example, the laser module 108 includes continuous-wave (CW) lasers with wavelengths of 355 nm, 391 nm, 399 nm, 370 nm, 638 nm, and 935 nm.

[0028] The RF port 110 and DC port 112 are conventional electrical feedthroughs that allow for external electrical connection of RF and DC electrical signals to the electrodes of the ion trap 202.

[0029] Figures 2A and 2B are schematic diagrams of the top view and cross-sectional view of an ion trap package according to an exemplary embodiment, respectively. The cross-sectional view shown in Figure 2B is cut through the line aa shown in Figure 2A.

[0030] The ion trap package 102 includes an ion trap 202 and an enclosure 204 that surrounds the ion trap in an ultra-high vacuum (UHV) environment.

[0031] Figure 3 shows the operation of a method suitable for forming an ion trap package according to an exemplary embodiment. Method 300 will be described with reference to Figures 1 and 2A to 2B, as well as to Figure 4. Method 300 begins with operation 301, in which an ion trap 202 is attached to a conventional chip carrier 206 and wire bonded.

[0032] Ion trap 202 is a conventional microfabricated surface ion trap. An example of a surface ion trap suitable for use as taught in this disclosure is the HOA 2.0 ion trap from Sandia National Laboratories. As those skilled in the art will understand, a microfabricated surface ion trap includes a plurality of electrodes arranged in two one-dimensional arrays on the surface of a substrate, defining a linear trap region TR between the linear arrays. The longitudinal axis of the trap region TR defines the trap axis TA.

[0033] The electrodes of the ion trap 202 are electrically coupled to bond pads wire-bonded to the RF port 110 and DC port 112 (not shown in Figures 2A-2B) to allow for the desired placement of RF and DC electrical signals in the ion trap.

[0034] The enclosure 204 comprises multiple piece parts, including a chip carrier 206 and a housing 208, which includes side walls 208A and a lid 208B. In some embodiments, the housing 208 is a unitary structure, which includes a continuous portion defining the side walls 208A and the lid 208B. For example, in some embodiments, the housing 208 is machined from a solid material block to form a single continuous element including the side walls 208A and the lid 208B.

[0035] In the illustrated example, the enclosure 204 also includes windows 214-1 to 214-3 attached to the side wall 208B, and window 214-4 attached to the lid 208B. Windows 214-1 to 214-4 are each installed in the housing 208 via UHV seals 210-1 to 210-4, so that the windows and UHV seals are substantially impermeable to low molecular weight gases such as hydrogen and helium. Preferably, windows 214-1 to 214-4 are formed of a single-crystal material that also mitigates the diffusion of low molecular weight gases.

[0036] In the illustrated example, each window is sealed to the housing 208 via a UHV seal, which is formed by first forming a brazed joint in the window and then electron beam welding the brazed joint to the housing.

[0037] In operation 302, the side wall 208A is joined to the lid 208B and the ion pump 104 at UHV seals 210-5 and 210-6, respectively. Each of the UHV seals 210-5 and 210-6 is substantially impermeable to low molecular weight gases such as hydrogen and helium. In the illustrated example, each of the UHV seals 210-5 and 210-6 is a welded joint.

[0038] In operation 303, the chip carrier 206 and the partially assembled enclosure, including the housing 208 and the ion pump 104, are loaded into the UHV assembly system 400.

[0039] Figure 4 is a block diagram of the UHV assembly system according to the present disclosure. The UHV assembly system 400 is an alignment / joining system that can align separate components and join them together while under UHV conditions. The UHV assembly system 400 includes a UHV chamber 402, a pump 404, an alignment system 406, a joining system 408, and a load lock 410.

[0040] UHV chamber 402 is 10 -9 This is an environmental chamber capable of maintaining a pressure below Torr.

[0041] The chip carrier, housing, and ion pump are located within the UHV chamber 402 via a load lock 404, which is a conventional portal that allows the piece parts to be loaded into the UHV chamber 402 without significant degradation of the UHV environment.

[0042] Pump 406 has a UHV chamber of 10 -9 This is a conventional UHV pump configured to evacuate to a pressure below Torr.

[0043] The alignment system 408 is a 6-degree-of-freedom alignment system that can achieve and maintain high-precision alignment between multiple piece parts.

[0044] In operation 304, a surface treatment such as ion sputtering is applied to at least one surface within the chamber 212. In the illustrated example, multiple surface treatments are performed, including argon ion beam treatment, plasma treatment, and heat treatment.

[0045] In operation 305, a getter surface 220 is formed on the lid 208B. In some embodiments, a conventional getter, such as a non-evaporative getter (NEG), is placed in the chamber 212.

[0046] In operation 306, the chip carrier 206 and the housing 208 are aligned.

[0047] In the illustrated example, the chip carrier 206 and housing 208 are aligned and joined such that the trap axis TR is oriented along the ion pump direction and the trap axis TA is oriented at an angle θ with respect to the propagation direction of the ablation signal 114. In the illustrated example, θ is approximately equal to 45° such that the ablation signal intersects the trap region TR diagonally.

[0048] Optical access to the ablation signal 114 is enabled by a window 214-1, which allows the ablation signal to access the material 218 in the crucible 216 to ablate the material and generate an atomic flux. In the illustrated example, the material 218 is ytterbium (Yb).

[0049] Similarly, optical access of the laser signal 116 to the ion trap 202 is made possible by window 214-2.

[0050] In the illustrated example, each of the UHV seals 210-1 to 210-6 is a laser-welded joint. In some embodiments, at least one of the UHV seals 210-1 to 210-6 is a different UHV seal, such as a compressible metal flange (e.g., a copper flange), a brazed joint, or a UHV-compatible solder ring containing, but not limited to, materials suitable for use in UHV systems, such as indium and gold-tin.

[0051] In operation 307, the chip carrier 206 and housing 208 are joined via the UHV seal 210-7. In the illustrated example, the UHV seal 210-7 is an indium-containing solder seal. The formation of the UHV seal 210-7 completes the enclosure 204, sealing the ion trap 202 within the chamber 212, which has an internal UHV environment equivalent to that inside the UHV chamber 402. In other words, the chamber 212 has a pressure of 10 at the completion of operation 304. -9 This includes the following environments.

[0052] In the illustrated example, the enclosure 204 has overall dimensions of approximately 130 mm × 100 mm × 70 mm when fully assembled. However, as will become apparent to those skilled in the art after reading this specification, these dimensions are illustrative only, and the enclosure 204 may have any practical physical dimensions without departing from the scope of this disclosure.

[0053] In the illustrated example, the joining system 410 is an indium sealing system configured to operate in a UHV environment, and the UHV seal 210-7 is an indium solder ring. However, joining systems other than laser welding systems can also be used to join piece parts under UHV conditions without departing from the scope of this disclosure. In some embodiments, for example, the joining system 410 includes a compressible metal flange compression system similar to those used in UHV deposition systems such as laser welding systems, soldering systems, and / or molecular beam epitaxy (MBE) systems and atomic layer epitaxy (ALE) systems.

[0054] In some embodiments, the joined enclosure 204 pieces include groove rings and frames that interlock to ensure a reliable seal when welded or joined via compressible metal flanges and / or UHV-compliant solder.

[0055] Although the enclosure 204 is assembled and joined with the ion pump 104 (except for seal 210-6) before being placed in the UHV chamber 402, in some embodiments more of the enclosure assembly is completed inside the UHV chamber itself (e.g., at least one of the windows 214-1 to 214-3 and / or a lid is joined to the side wall 208A, and / or the side wall 208A is joined to the chip carrier 206, etc.). Furthermore, in some embodiments, the fully or partially assembled enclosure 204 and ion pump 104 are joined while they are inside the UHV chamber.

[0056] In aspects of this disclosure, only UHV seals are used to join the enclosure pieces, and the internal chamber is 10 -9 By sealing the enclosure while the pressure is below Torr, the embodiment offers the following significant advantages over prior art ion trap systems. • Elimination of unreliable pinch-off tubes, or • Capable of operating at temperatures exceeding extremely low temperatures (e.g., above -50°C), or • Significantly smaller overall volume of the ion trap system, or • An ion trap system that does not use a cryogenic pump is possible, or • Any combination of i, ii, iii, and iv.

[0057] For example, in an exemplary embodiment, the chamber 212 is approximately 2 cm 3 It has only a volume of 2 cm³. In some embodiments, the volume of chamber 212 is 2 cm³. 3 Surprisingly, 10cm 3 It is preferable that it be less than [a certain value].

[0058] In any operation 308, the pressure in the chamber 212 is set to 10 -10 The pressure is reduced to below Torr. In the illustrated example, the ion pump 104 reduces the pressure inside the chamber 104 to 2 × 10⁻⁶. -11 Reduce the value to below Torr.

[0059] As will be apparent to those skilled in the art, the vacuum quality within a captured ion system determines the lifetime of the ion chain. Collisions involving sufficient kinetic energy transfer between residual background gas molecules and captured ions can severely destroy the captured ion chain; therefore, the elastic collision rate between them is a critical parameter for captured ion-based quantum computers. To reliably maintain the ion chain over the period required for quantum computation, the vacuum degree must be (preferably about 10°C). -11 It must be within an ultra-high vacuum region (above Torr).

[0060] Another aspect of the present disclosure is that the pressure in the chamber 212 can be measured (or estimated) by monitoring the behavior of one or more captured ions.

[0061] Figure 5 shows the operation of a method for monitoring pressure within an ion trap system according to the present disclosure. Method 500 begins with operation 501, which forms a double well potential within the ion trap 202.

[0062] Figure 6A shows a simulation of the double well potential according to this disclosure.

[0063] Plot 600 shows the ionic potential as a function of axial position under the condition that the height of the potential barrier between wells W1 and W2 has a minimum value significantly lower than the average energy transfer from the collision event (i.e., collision energy).

[0064] In operation 502, the potential barrier between the two wells is controlled. In the illustrated example, the height BH of the potential barrier is given by the average collision energy given by the following equation. <ei> θ It is controlled to be 50 μeV, which is about 40 times lower than that. TIFF0007856959000001.tif11150(1) Here, mi and mm are the masses of the ions and background gas molecules in the trap, v is the relative velocity of the ions and background gas molecules, θ is the scattering angle, and Em is the initial kinetic energy of the background gas molecules. In this example, the ions 174 Yb + Therefore, the background gas molecule is H2, and thus by equation (1), the average collision energy <ei> θ The voltage is estimated to be approximately 2 meV. Under these conditions, all collision events are expected to randomize ion positions.

[0065] In operation 503, the position of a single captured ion is monitored between wells W1 and W2. In the illustrated example, the position of the captured ion is determined by imaging the ion position with an electron-multiplier CCD (EMCCD) camera to determine which of the two wells contains the ion.

[0066] Figure 6B is a plot of the positions of trapped ions between wells in a double-well potential as a function of time, according to the present disclosure.

[0067] Plot 602 shows the ion position as a function of time (i.e., the transition rate) by displaying the sample trace of the total EMCCD signal count of pixels within the regions where the minimum values ​​of the two potential wells are located (designated as Region 1 and Region 2).

[0068] In operation 504, the ratio of ion transitions between wells W1 and W2 is determined. This transition rate is extracted from plot 602. In the illustrated example, the transition rate is one event every 32 minutes. Since the ions are eventually Doppler-cooled into one of the wells after collision, the actual collision rate is expected to be approximately twice the measured transition rate.

[0069] In operation 505, the pressure inside the chamber 212 is estimated based on the extracted collision coefficient. The relationship between the collision coefficient γ and the pressure inside the chamber 212 is given by the following equation: TIFF0007856959000002.tif14150(2) Here, P is the pressure inside chamber 212, Q is the net charge of the trapped ions, T is the temperature, α is the polarizability of the background molecules, and ε0 is the permittivity of vacuum.

[0070] In the illustrated example, γ = 1 / (16 min), and μ ≈ mH2 = 3.32 × 10 -32 It is kg and αH2=8 * 10 -31 m 3 Therefore, T=300K. As a result, the pressure P at the ion position is 2.2 × 10⁻⁶ -11 It becomes equal to Torr.

[0071] In some embodiments, the pressure inside the UHV chamber is estimated based on the reordering rate of ions in the ion chain held within the ion trap.

[0072] Figure 7 shows the operation of another method for monitoring pressure in an ion trap system according to the present disclosure. Method 700 begins with operation 701, in which isotopes of ions having at least one distinct property are selected to be included in the ion chain to be trapped in the ion trap 202. By selecting ions with different properties, the order of ions in the ion chain can be determined. In the illustrated example, the isotopes are 174 Yb + and 172 Yb + These ions are selected and appear as bright and dark ions, respectively, within the ion trap system 100. In some embodiments, different properties selected for multiple isotopes differ from brightness. Other properties that can be selected to distinguish isotopes according to this disclosure include, but are not limited to, ion species and ion isotopes.

[0073] In operation 702, the collision energy required to cause an observable rearrangement event in the ion chain is estimated.

[0074] In operation 703, the selected ion chain is captured in the ion trap 202. In the illustrated example, the ion chain consists of four 174 Yb + ions and two 172 Yb + It contains ions. Note that small differences in isotope masses do not significantly alter the expected 2.2 meV energy barrier and can therefore usually be ignored.

[0075] Although the ion chain contains multiple isotopes, only one is in resonance with the Doppler-cooled laser (370 nm in the illustrated example), and therefore only this isotope is detected by the EMCCD camera. In the illustrated example, 174 Yb + The ions are selected as bright ions, and two 172 Yb + The ions remain dark.

[0076] To estimate this collision energy, we consider the energy difference between (1) a first chain configuration in which the ions are aligned along the trap axis in their typical arrangement, and (2) a second chain configuration in which two of the ions are pushed onto one of the horizontal axes.

[0077] Figure 8A shows the first and second chain configurations used to estimate the collision energy of the six-ion chain in Method 700.

[0078] If the same ion is stationary within the trap, the total energy of the chain is given by the following equation: TIFF0007856959000003.tif25121 Here, m is the mass of the ion, and ω x、y、z These are the trap frequencies in the x, y, and z directions, respectively, and R i =( X i , Y i , Z i ) is the equilibrium position of the i-th ion in the trap, and Q is the charge of the ion.

[0079] In the illustrated example, ω x、y ω is equal to 2.7MHz, z This is equal to 0.32 MHz. As a result, the energy difference between the first and second chain configurations can be determined to be approximately 2.2 meV.

[0080] As a result, it can be predicted that a rearrangement event occurs when the ion chain gains an energy exceeding approximately 2.2 meV through a collision event. This value is close to the estimated average energy exchange in a single collision event given by equation (1) above. Therefore, since approximately half of the background molecules will have an energy exceeding 2.2 meV, it can be predicted that one out of two collision events will trigger a rearrangement event.

[0081] In operation 704, the order of ions in the ion chain is monitored via an EMCCD camera.

[0082] In operation 705, the time interval between ion rearrangement events is determined.

[0083] Figure 8B shows a histogram of the time intervals between ion rearrangement events. Plot 800 shows the rearrangement interval time in a 2-minute time bin for ion chain rearrangement events recorded over 15 hours.

[0084] As shown in plot 800, 54 reordering events were recorded, with an average reordering rate of approximately one event every 15.8 minutes. It is estimated that only about two-thirds of the reordering events were detected because some adjacent ion pairs are identical isotopes. As a result, applying a correction factor to the recorded data, the "true" reordering rate is approximately one event every 10.5 minutes.

[0085] Assuming that all ion-molecular collisions that resulted in transitions triggered rearrangement events, a rearrangement rate of one event can be predicted every 5.3 minutes based on a simple multiplication of the collision rate for two ion chains, taking into account six ion chains. Considering that the energy required for a rearrangement collision event is approximately 2.2 meV, similar to the estimated average energy exchange during a collision event, it is reasonable that the measured rearrangement rate will be approximately half of the collision rate.

[0086] In operation 706, the pressure inside the chamber 212 is estimated based on the ion chain rearrangement rate.

[0087] This disclosure teaches only a few examples of embodiments provided herein, and it should be understood that those skilled in the art will readily be able to devise many modifications of the invention after reading this disclosure, and that the scope of the invention should be determined by the following claims. [Explanation of Symbols]

[0088] 100 Ion Trap System 102 Ion Trap Package 104 Ion pump 106 Ablation Laser 108 Laser Modules 110 RF ports 112 DC ports 114 Ablation signal 116 Laser signals< / ei> < / ei>

Claims

1. It is an ion trap system, An ion trap placed on a chip carrier, An enclosure that seals the ion trap in the first chamber, The enclosure comprises a plurality of piece parts including the chip carrier and the housing, the piece parts of the plurality of piece parts are joined by a plurality of seals consisting of UHV seals, and at least one of the plurality of seals comprises at least one of a welded joint and a brazed joint. The first chamber is 10 -10 Having a pressure of Torr or less, The first chamber is 10 cm 3 It has the following internal volume, The ion trap system has an operating temperature of -50°C or higher. In a UHV chamber, which is an environmental chamber capable of maintaining a pressure of 10⁻⁹ Torr or less, the piece parts of the enclosure are joined using only the UHV seal, and the enclosure is sealed while the first chamber has a pressure of 10⁻⁹ Torr or less. All of the aforementioned piece parts are sealed with the UHV seal only. The ion trap system does not use a cryostat, vacuum valve, or pinch-off tube. An ion trap system characterized by the following features.

2. It also features an ablation oven, The ion trap system according to claim 1.

3. The aforementioned plurality of piece parts include a first window, The ion trap system according to claim 2.

4. The first window includes a single-crystal material that suppresses the diffusion of low-molecular-weight gases through the window. The ion trap system according to claim 3.

5. The enclosure includes a first surface which is activated to adsorb gas molecules, The ion trap system according to claim 1.

6. (1) further comprising a getter material and (2) an ion pump, The ion trap system according to claim 1.

7. It is an ion trap system, An ion trap placed on a chip carrier, An enclosure comprising a plurality of piece parts including the chip carrier and housing, which seals the ion trap in the first chamber, Multiple seals, each made of a UHV seal, join the multiple piece parts together. An ion pump joined to the enclosure via a first UHV seal, Equipped with, At least one of the plurality of seals includes at least one of a welded joint and a brazed joint, The first chamber is 10 -10 Having a pressure of Torr or less, The aforementioned ion trap system does not use a cryo-adsorption pump. The ion trap system is configured to enable an operating temperature of -50°C or higher. In a UHV chamber, which is an environmental chamber capable of maintaining a pressure of 10⁻⁹ Torr or less, the piece parts of the enclosure are joined using only the UHV seal, and the enclosure is sealed while the first chamber has a pressure of 10⁻⁹ Torr or less. All of the aforementioned piece parts are sealed with the UHV seal only. The ion trap system does not use a cryostat, vacuum valve, or pinch-off tube. An ion trap system characterized by the following features.

8. The first chamber is 10 cm 3 The ion trap system according to claim 7, having the following internal volume.

9. It also features an ablation oven, The ion trap system according to claim 7.

10. The enclosure further includes a first window joined to the enclosure in a second UHV seal, the second UHV seal includes at least one of a welded joint and a brazed joint. The ion trap system according to claim 9.

11. The window includes a single-crystal material that suppresses the diffusion of low-molecular-weight gases through the window. The ion trap system according to claim 10.

12. The enclosure includes a first surface which is activated to adsorb gas molecules, The ion trap system according to claim 7.

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