Particle collision device and method for determining a triboelectric charge transfer

Abstract

The invention relates to a particle collision device (10) for detecting an electrical charge after collision of a particle (12) with a collision partner (14), comprising an acoustic particle holding device (16), a particle preparation device (32) for modifying at least one particle property of the particle (12), a collision partner (14), and a charge detector (28) designed to detect an electrical charge of the particle (12) and / or of the collision partner (14) after a collision of the particle (12) and the collision partner (14).

Description

[0001] ” ' i ) in te ll ec tualproper ty

[0002] Federal Physical-Technical Institute Lawyer's file:

[0003] Braunschweig and Berlin 0454-0334 PCT-1

[0004] Bundesallee 100

[0005] 38116 Braunschweig Date:

[0006] October 23, 2025

[0007] Particle collision device and method for determining a triboelectric charge transfer

[0008] The invention relates to a particle collision device for detecting an electrical charge after a collision of a particle with a collision partner. According to a second aspect, the invention relates to a method for determining a triboelectric charge transfer.

[0009] When particles are transported in a powder stream, electrostatic charges are generated in the powder. These electrical charges are due to the triboelectric effect, i.e., the exchange of charges upon contact between two solids. During the powder flow in a device, such as a mixer or silo, this triboelectric effect leads to electrostatic charges at the contact between the solid powder particles and at the contact surface between these particles and the material.

[0010] The device causes the conveyed material to become electrostatically charged. If the particles form a flammable, especially organic, powder, this powder may explode or ignite if a spark is generated due to the electrostatic charge. Therefore, attempts are made to characterize the charge of powders in order to prevent such sparking.

[0011] The following approaches are conceivable: On the one hand, the powder can be characterized as an ensemble of particles. This method is straightforward, but only the average charge values ​​are determined. On the other hand, the charge transfer to a single particle during a collision can be measured. However, this method is hardly suitable for preparing particles of different sizes.

[0012] It is desirable to be able to effectively investigate charge transfer due to collisions between two particles. WO 2017 / 085613 describes a device for determining the weight of a particle, particularly for drug manufacturing, using standing acoustic waves. The device has a measuring instrument with which electrical charges in the vicinity of the particle to be weighed can be determined. However, such a device is not suitable for studying triboelectric effects during collisions.

[0013] The article “The effect of electrostatic charges on particle-laden duct flows” by Grosshans et al., J. Fluid Meeh. (2021), vol. 909, A21 describes the influence of electrostatic charge on particle-laden flows. Collisions between particles are considered, but the resulting triboelectric charges are not taken into account.

[0014] DE 10 2021 101 409 B3 describes a method for determining at least one charge characteristic of the electrical charges of particles in a fluid flow. A gas flow containing particles is passed through a measuring line, and the particle velocities are measured once with an electric field and once without. The electrical charge of the particles is then determined by comparing the two particle velocities. Changes in particle charge due to collisions are not considered.

[0015] The invention is based on the objective of making the charge transfer between a particle and a collision partner measurable.

[0016] The invention solves the problem by means of a device comprising (a) an acoustic particle holding device, (b) a particle preparation device for changing at least one property of the particle, in particular its charge, (c) a collision partner and (d) a charge detector designed to detect an electrical charge of the particle and / or the collision partner after a collision of the particle and the collision partner.

[0017] According to a second aspect, the invention solves the problem by a method for determining a triboelectric charge transfer, comprising the steps of (a) holding a particle in a particle collision device according to the invention, (b) setting a predetermined property, in particular a charge, of the particle, (c) releasing the particle from a particle holding device of the particle collision device so that the particle collides with a collision partner, and (d) measuring a change in the charge of the particle and / or the collision partner after the collision.

[0018] For the purposes of this description, a particle is understood to be an object having an aerodynamic diameter of at least 200 micrometers, in particular at least 200 micrometers and at most 15 millimeters, in particular at most 10 millimeters. The term particle can also be used instead of particle.

[0019] An acoustic particle holding device is understood to be, in particular, a device that holds the particle in a predetermined location using sound waves. The particle holding device could also be referred to as a particle levitation device.

[0020] A collision partner is understood in particular to be an object that is arranged in such a way that it is brought into collision with the particle or at least arranged to collide with the particle.

[0021] A charge detector is understood to be, in particular, a measuring device by means of which a change in the electrical charge of the particle, or the electrical charge of the particle before and / or after the collision, can be measured. For example, the charge detector is a Faraday cup. The charge detector preferably comprises an electrometer connected to the Faraday cup.

[0022] A particle collision device is understood to be, in particular, a device by means of which the particle can be brought into collision with the collision partner and the charge change of the particle and / or the collision partner caused by the collision can be determined.

[0023] An advantage of the invention is that the change in charge of the particle and / or the collision partner can generally be measured directly. In other words, the change in charge on individual particles is measured.

[0024] A further advantage is that the particle collision device allows the adjustment and / or measurement of the charge of the particle and / or the collision partner before the collision. This makes it possible to investigate the charge transfer during particle-collision partner contact. In addition, the effects of particle properties and / or environmental conditions on the charge transfer can be examined.

[0025] Another advantage is that the shape of the particles is not limited to spherical. While spherical particles can be used, other shapes are also possible.

[0026] It is advantageous that the particle and the collision partner can collide at an angle. This means, in particular, that the particle's trajectory after the collision runs at an angle, especially of more than 10°, to the direction the particle had immediately before the collision.

[0027] Another advantage is that the particles can collide with each other at higher speeds than in prior art methods.

[0028] According to a preferred embodiment, the particle holding device comprises an ultrasonic generator and an ultrasonic reflector for reflecting the ultrasound emitted by the ultrasonic generator. The ultrasonic reflector is particularly arranged such that the ultrasound generated by the ultrasonic generator forms a standing wave field by means of which the particle is held in a predetermined location.

[0029] Preferably, the particle collision device comprises an environmental parameter meter, for example a thermometer and / or a hygrometer, for measuring at least one environmental parameter of the environment of the particle and / or the collision partner.

[0030] Preferably, the particle and / or the collision partner is made of an electrical insulator. An electrical insulator is defined as a substance whose conductivity under standard conditions is less than 10 -8 Siemens per meter.

[0031] According to one embodiment, the particle holding device can be brought into a holding state, in which the particle is held or can be held in the particle holding device, in particular permanently and / or in one location, and into a release state, in which a particle held in the particle holding device leaves the particle holding device. For example, the release state is achieved by ceasing the emission of the sound waves by means of which the particle can be held in the particle holding device.

[0032] Preferably, the acoustic particle holding device is arranged relative to the collision partner in such a way that a particle held in the particle holding device can be set into motion, in particular only by bringing the particle holding device from the holding state to the release state, in a manner that leads to a collision with the collision partner.

[0033] According to a preferred embodiment, the particle preparation device has a charge-changing device for changing the charge of the particle held by the particle-holding device. A charge-changing device is understood to be, in particular, a device by means of which the charge of the particle can be selectively changed.

[0034] The charge-changing device has, for example, a source of ionizing radiation, such as X-rays, gamma rays, alpha radiation, or beta radiation. X-rays or gamma rays can be used to discharge the particle. Alpha radiation can increase the (positive) charge of the particle, while beta radiation can decrease it.

[0035] Alternatively, the charge-changing device can include an ion generator configured to fire ions at the particle. For example, the ion generator is a corona discharge generator for producing a corona discharge that comes into electrical contact with the particle.

[0036] Alternatively or additionally, the particle preparation device preferably includes a particle surface conditioning device for conditioning a particle surface. The particle surface conditioning device is, for example, an atmosphere control device for adjusting the atmosphere surrounding the particle. For instance, the atmosphere control device is configured to adjust the humidity and / or temperature of the atmosphere surrounding the collision partner. Changing the humidity and / or temperature alters the adsorption of water on the particle surface. Alternatively or additionally, the particle collision device preferably includes a collision partner surface conditioning device for conditioning a collision partner surface.The contact partner surface conditioning device is preferably an atmosphere adjustment device for setting an atmosphere surrounding the contact partner. For example, the atmosphere adjustment device is designed to set the humidity and / or temperature of the atmosphere surrounding the contact partner.

[0037] According to one embodiment, the collision partner is arranged in the charge detector. In this way, a particularly precise measurement of the charge change of the collision partner is possible.

[0038] Preferably, the charge detector has (i) a charge detector inlet opening for the particle coming from the particle holding device and (ii) a charge detector outlet opening for the particle after a collision with the collision partner. It is possible, but not necessary, for the charge detector inlet opening to differ from the charge detector outlet opening.

[0039] According to one embodiment, the collision partner is arranged in the charge detector such that the particle coming from the particle holding device enters the charge detector through the charge detector inlet opening, collides with the collision partner, and then exits the charge detector through the charge detector outlet opening. In this way, the charge change of the collision partner and / or the particle can be determined with particularly low measurement uncertainty.

[0040] According to one embodiment, the particle-holding device has a trap volume in which the particle is held by acoustic levitation during operation of the device. The trap volume is the area of ​​space in which the particle can be held for a theoretically unlimited time, for example, at least 10 minutes, and in particular at least 1 hour. Preferably, the trap volume is at least twice, and in particular at least five times, the size of the particle.

[0041] According to one embodiment, the particle holding device has a holding device outlet opening. The holding device outlet opening is preferably arranged such that the particle can be transferred out of the particle holding device through the holding device outlet opening. This is preferably achieved by terminating the levitation, in particular by reducing, and especially by terminating, the ultrasonic emission from the ultrasonic generator.

[0042] According to a preferred embodiment, the holding device's discharge opening is arranged below the trap volume. In this way, the particle moves along a ballistic trajectory (downwards) that is easily predictable. This, in turn, allows the velocity at which the particle impacts the collision partner to be determined with low measurement uncertainty.

[0043] According to one embodiment, the particle collision device has an evaluation unit. The evaluation unit is preferably designed to automatically perform a method comprising the steps of (i) detecting an inlet charge change in the charge detector as the particle enters the charge detector, (ii) detecting an outlet charge change in the charge detector as the particle exits the charge detector, and (iii) determining the particle charge and / or the particle charge change from the inlet charge change and the outlet charge change. In this way, the particle charge and / or the particle charge change can be determined with low measurement uncertainty.

[0044] This is especially true if the charge detector is a Faraday cup. In this case, the voltage between the Faraday cup and zero potential (ground) is directly proportional to the charge of the entering and exiting particles. By calculating the difference between the voltage before the particle enters and after it exits, the particle's charge can be determined (by multiplying this difference by a prefactor determined through calibration). Alternatively, the particle's charge can be determined by calculating the difference between the charge that flowed onto or from the Faraday cup after the particle entered it and the charge that flowed onto or from the Faraday cup after the particle exited it.

[0045] The impact partner is preferably also a particle, which is called the impact particle. According to one embodiment, the particle collision device has a particle gun for firing the impact particle at the impact particle. Preferably, the particle gun has a tube for firing the particle by means of gas pressure and / or a particle velocity adjustment device by means of which the exit velocity of the particle can be adjusted. For example, the exit velocity of the particle depends on a gas pressure by which the particle is accelerated in the tube. By adjusting the gas pressure, the exit velocity can thus be adjusted.

[0046] For example, the particle gun is designed to emit the impact particle at a speed of at least 8 m / s, in particular at least 10 m / s and / or at most 40 m / s, in particular at most 30 m / s.

[0047] Preferably, the particle gun has an exit velocity measuring device for measuring the exit velocity. The exit velocity measuring device can, for example, include a camera that determines the velocity based on the captured images, and / or light barriers arranged at a known distance from each other, so that the particle velocity can be calculated from the times at which the particle is detected passing through the individual light barriers.

[0048] Preferably, the particle holding device has a camera for recording images of the particle and / or the collision partner. In particular, the images have a timestamp so that the velocity, especially a vectorial velocity, of the particle and / or the collision partner can be calculated.

[0049] Preferably, the particle holding device is designed to control the particle's position based on the images. For example, if an acoustic levitation device is used, the particle's position depends on the strength of the ultrasonic field. By changing the power of the ultrasonic generator, the particle's position can be altered so that it assumes a predetermined position.

[0050] Alternatively or additionally, the particle holding device is configured to determine a velocity, particularly a vectorial velocity, of the particle and / or the collision particle based on the images. For example, the particle holding device is configured to determine a collision angle based on the images. The collision angle is the angle between the two trajectories of the particle and the collision particle after the collision. Preferably, the particle holding device is configured to determine the collision angle based on the images. The collision angle is the angle between the trajectories of the particle and the collision partner before the collision.

[0051] According to one embodiment, the charge detector has (a) a first electrode, (b) a second electrode, and (c) a voltage source for applying a voltage between the first and second electrodes, so that an electric field is formed between the electrodes. As a result, the trajectory of the particle and / or, if applicable, the collision particle also depends on the electric field, so that the particle's charge and / or velocity can be determined from its trajectory. The same applies to the collision particle.

[0052] Preferably the charge detector (d) has a detector camera for detecting a target particle trajectory of the collision partner after a collision with the particle and / or a particle trajectory of the particle after a collision with the collision partner, wherein (e) the electrodes are arranged such that the collision particle trajectory and / or the particle trajectory runs between the electrodes, and wherein (f) the evaluation unit is designed for automatically calculating the charge and / or the, in particular vectorial, velocity of the collision partner from the collision particle trajectory and / or the charge and / or the, in particular vectorial, velocity of the particle from the particle trajectory.

[0053] The charge detector can include a Faraday cup, preferably positioned behind the electrodes with respect to the particle trajectories, so that the particle and / or the collision particle is collected within it. This Faraday cup serves as additional validation for the measured charge of the particle and / or the collision particle based on their respective trajectories.

[0054] According to one embodiment, the particle collision device has a particle accelerator arranged to accelerate the particle to a predetermined particle velocity. Preferably, the particle accelerator is arranged downstream of the particle holding device with respect to the particle's trajectory.

[0055] The invention will now be explained in more detail with reference to the accompanying drawings. Figure 1a shows a particle collision device according to a first embodiment of the invention and

[0056] Figure 1b shows a particle collision device according to a second embodiment of the invention.

[0057] Figure 1a shows a particle collision device 10 according to the invention for detecting an electrical charge Q12 of a particle 12 after a collision with a collision partner 14. The collision partner 14 can, as in the present case, be arranged in a fixed position and then be referred to as the target 15. The particle 12 is held in a trap volume V16 by means of a particle holding device 16. The particle holding device 16 has an ultrasonic generator 18 and an ultrasonic reflector 20, between which a standing ultrasonic wave field 22 is formed, by means of which the particle 12 is held in the trap volume V16.

[0058] When the ultrasound generator 18 is switched off, the particle 12' falls through a retention opening 24. All reference symbols 12 denote the particle in different positions. After a predetermined fall distance, the particle 12' enters a charge detector 28 through a charge detector inlet 26, collides with the collision partner 14, and exits the charge detector 28 through a charge detector outlet 30.

[0059] The particle collision device 10 has a particle preparation device 32, in the illustrated case in the form of a charge conversion device 33, which may, but need not, be formed by a corona discharge device 34. The corona discharge device 34 has a tapered electrode 36 to which a high voltage, for example pulsed or alternating, is applied relative to ground. This results in a corona discharge that transfers charges to the particle 12. The particle 12 is exposed to the corona discharge until it has a predetermined particle charge Q12. The particle charge Q12 is a particle property.

[0060] The charge detector 28 can be configured as a Faraday cup 29, as in the present case, but this is not necessary. The Faraday cup is held at a predetermined constant detector voltage U28 relative to ground by an evaluation unit 38. When the particle 12' enters the Faraday cup 29, the particle charge Qi2 is transferred to the Faraday cup 29. To compensate for this particle charge Qi2, a current Imess.ein flows between the Faraday cup 29 and ground, which is measured directly or indirectly and corresponds to an inlet charge change of the charge detector 28. This inlet charge change Imess.ein is proportional to the particle charge Q12. Therefore: Imess.ein = k*Qi2.

[0061] When particle 12"" leaves the charge detector 28 after the collision with the collision partner 14, an exit charge change Imeasured results, which is proportional to the particle charge Q'12 of particle 12"" after the collision. The charge Q14 transferred to the collision partner 14 can thus be calculated as Qi4 = Q12 - Q'i2 = (Imeasured / k - Imeasured / k) = (Imess.in- lmess.out) / k.

[0062] Along a particle trajectory T12 of the particle 12, a particle accelerator 40 can be arranged between the particle holding device 16 and the collision partner 14, which accelerates the particle 12' positively or negatively. For this purpose, the particle accelerator 40, which is preferably a linear accelerator, has, for example, electrodes 42.1, 42.2. The electrodes 42.1, 42.2 are subjected to an accelerating voltage UB by a control unit 44, which may, but need not, be part of the evaluation unit 38, such that the particle 12' has a predetermined particle velocity V12 when it hits the collision partner 14.

[0063] Figure 1b shows a second embodiment of a particle collision device according to the invention. The particle 12 is held by the particle holding device 16 in the falling volume V16 and brought into collision with the collision partner 14, which is formed by a collision particle 46.

[0064] The impact particle 46 is accelerated to a predetermined impact particle velocity V46 by means of a particle gun 48. The particle gun 48 can, for example, have a tube 50 which is pressurized with pressurized gas 54 from a pressurized gas reservoir 56 via a gas pressure supply 52, thus accelerating the impact particle. The particle gun 48 is positioned at a distance from the trap volume V16 such that escaping gas does not blow the particle 12 out of the trap volume V16. Alternatively, an aperture 57 is arranged between the tube 50 and the particle holding device 16. The aperture 57 is positioned so that the impact partner 14 can pass through it, and the majority of the gas is deflected in such a way that it does not affect the particle 12.The particle holding device 16 has a camera 58 for recording images of the particle 12 as a function of time t, on the basis of which the ultrasound generator 18 is controlled, for example by the evaluation unit 38, so that the particle 12 is held at a predetermined location.

[0065] After the collision of the collision partner 14, in the form of the collision particle 46, with the particle 12, the particle 12' flies along its particle trajectory T12 and the collision particle 46' along a collision particle trajectory T46. The particle trajectory T12 and the collision particle trajectory T46 pass through the charge detector 28.

[0066] In the present embodiment, the charge detector 28 has a first electrode 60.1 and a second electrode 60.2, between which a voltage of 60° can be applied by means of a high-voltage source 62, so that an electric field E is formed. The trajectories T12 and T46 are recorded over time by means of a camera, for example a second camera 64, and transmitted to the evaluation unit 38. The evaluation unit 38 calculates the respective charges Q12 and Q46 from the trajectories, the known masses mi2 of particle 12 and rri46 of the collision particle 46, and their respective charges.

[0067] It is possible, but not necessary, that particle 12 and the collision particle 46 are subsequently captured by at least one Faraday cup 66.

[0068] Figures 1a and 1b show that the preparation device 32 can include a particle surface conditioning device 68 by means of which a particle surface of the particle 12 can be modified. For example, the particle surface conditioning device 68 is configured to release water vapor or air of a predetermined humidity and / or temperature, so that the amount of water adsorbed on the particle surface can be adjusted. In addition, the particle surface conditioning device 68 can be configured to release a substance other than water, for example, a solvent or an aerosol.

[0069] In the context of scientific investigations, for example, the material of the particle and / or the collision partner, their temperatures, their charges, and / or the molecules adsorbed on the surface and their quantity can be varied. Camera 58 and / or camera 64 are preferably high-speed cameras for recording at least 200 frames per second.

[0070] Reference symbol list

[0071] 10 Particle collision device 66 Faraday cups

[0072] 12 particles 68 particle surface conditioning

[0073] 14 impact partner rung device

[0074] 16 Particle holding device with 2 mass of the particle

[0075] 18 Ultrasound generator rri46 Mass of the impact particle

[0076] 20 Ultrasonic reflector Q12 particle charge

[0077] 22 ultrasonic wave field T12 particle trajectory

[0078] 24 Holding-out-exit opening T46 Shock particle trajectory

[0079] 26 Charge detector entry opening U28 Detector voltage

[0080] 28 Charge detector UB Acceleration voltage

[0081] 30 Charge detector outlet V12 particle velocity

[0082] 32 Preparation device V16 Trap volume

[0083] 33 Charge changing device

[0084] 34 Corona discharge device

[0085] 36 electrode

[0086] 38 evaluation units

[0087] 40 particle accelerators

[0088] 42 electrode

[0089] 44 Control unit

[0090] 46 impact particles

[0091] 48 particle cannon

[0092] 50 pipe

[0093] 52 Gas pressure supply

[0094] 54 Compressed gas

[0095] 56 compressed gas storage tanks

[0096] 57 aperture

[0097] 58 Camera

[0098] 60 electrode

[0099] 62 High-voltage source

[0100] 64 second camera

Claims

1. in te ll ec tualproper ty Federal Physical-Technical Institute Lawyer's file: Braunschweig and Berlin 0454-0334 PCT-1 Bundesallee 100 38116 Braunschweig Date: October 23, 2025 Patent claims 1. Particle collision device (10) for detecting an electrical charge after a collision of a particle (12) with a collision partner (14), with (a) an acoustic particle holding device (16), (b) a particle preparation device (32) for modifying at least one particle property of the particle (12), (c) a collision partner (14) and (d) a charge detector (28) designed to detect an electrical charge of the particle (12) and / or the collision partner (14) after a collision of particle (12) and collision partner (14).

2. Particle collision device (10) according to claim 1, characterized in that (a) the particle holding device in (i) a holding state in which the particle is held in the particle holding device, as well as (ii) capable of being brought into a release state in which a particle held in the particle holding device leaves the particle holding device and (b) the acoustic particle holding device is arranged relative to the collision partner in such a way that a particle held in the particle holding device can be set into motion by bringing the particle holding device from the holding state to the release state, in such a way as to cause a collision with the collision partner.

3. Particle collision device according to one of the preceding claims, characterized in that the particle preparation device (32) (a) a charge-changing device (33) for changing the charge of the particle (12) held by the particle-holding device (16) and / or (b) a particle surface conditioning device for conditioning a particle surface of the particle (12), which preferably includes an atmosphere adjustment device for adjusting an atmosphere surrounding the collision partner (14).

4. Particle collision device (10) according to claim 2, characterized in that the charge changing device (33) (a) a source of ionizing radiation, in particular X-rays, and / or (b) comprising an ion generator arranged to shoot ions at the particle (12).

5. Particle collision device (10) according to one of the preceding claims, characterized in that (a) the collision partner (14) is arranged in the charge detector (28), in particular a Faraday cup (66) and (b) the charge detector (28) (i) a charge detector inlet opening (26) for the particle (12) coming from the particle holding device (16) and (ii) has a charge detector outlet opening (30) for the particle (12) after a collision with the collision partner (14), (c) wherein the collision partner (14) is arranged in the charge detector (28) such that the particle (12) coming from the particle holding device (16) enters through the charge detector inlet opening (26), collides with the collision partner (14) and then exits the charge detector (28) through the charge detector outlet opening (30).

6. Particle collision device (10) according to one of the preceding claims, characterized in that the particle holding device (16) (a) has a trap volume (Vi6) in which the particle (12) is held by acoustic levitation during operation of the particle holding device (16), and (b) has a holding device outlet opening (24) which is arranged such that the particle (12) can be transferred out of the particle holding device (16) through the holding device outlet opening (24), in particular by terminating the levitation.

7. Particle collision device (10) according to one of the preceding claims, characterized by an evaluation unit (38) configured for automatically performing a method comprising the steps (i) Detecting an entry charge change in the charge detector (28) upon entry of the particle (12) into the charge detector (28) and (ii) Detecting an exit charge change in the charge detector (28) when the particle (12) exits the charge detector (28) and (iii) Determining a particle charge of particle (12) from the inlet charge change and the outlet charge change.

8. Particle collision device (10) according to one of the preceding claims, characterized by a particle gun (48) for shooting the particle (12) at the collision partner (14), which (a) has a tube (50) for shooting the particle (12) by means of gas pressure and / or (b) has a particle velocity adjustment device by means of which an exit velocity of the particle (12) can be adjusted.

9. Particle collision device (10) according to claim 8 or 0, characterized in that the particle holding device (16) (a) has a camera (58) for taking pictures of the particle (12) and (b) is trained to control the position of particle (12) using the images.

10. Particle collision device (10) according to one of the preceding claims, characterized in that the charge detector (28) (a) a first electrode (36), (b) a second electrode (36) and (c) a voltage source for applying a voltage between the first electrode (36) and the second electrode (36) such that an electric field is formed between the electrodes (36), and (d) a detector camera (58) for detecting a collision particle trajectory of the collision partner (14) after a collision with the particle (12) and / or a particle trajectory (T4Ö) of the particle (12) after a collision with the collision partner (14), (e) wherein the electrodes (36) are arranged such that the impact particle trajectory and / or the particle trajectory (T4O) runs between the electrodes (36), and (f) wherein the evaluation unit (38) is configured to automatically calculate the charge of the collision partner (14) from the collision particle trajectory and / or the charge of the particle (12) from the particle trajectory (T4Ö).

11. Method for determining a triboelectric charge transfer, comprising the steps (a) Holding a particle (12) in a particle collision device (10) according to any one of the preceding claims, (b) Adjusting a predetermined particle property, in particular a charge, of the particle (12), (c) Release of the particle (12) from a particle holding device (16) of the particle collision device (10) so that the particle (12) collides with a collision partner (14) and (d) Measuring a change in the charge of the particle (12) and / or the collision partner (14) after the collision.

Images