The Capability of Key Micropattern Detectors to Suppress Ion Back Flow

Electrons And Ions ◽

Time Projection ◽

Positive Ion

In this chapter, the authors discuss the unique ability of some micropattern detectors, in particular, GEM, MHSP, COBRA, and MICROMEGAS, to suppress the positive ion flow from the multiplication region of the detector back to the drift space. This effect is based on how electrons and ions move in these detectors. It will be shown that an optimized cascaded detector can so efficiently block the ion back flow that only 10-3% of the avalanche ions can penetrate back into the drift region. This feature makes these detectors attractive for applications such as photodetectors combined with highly efficient solid photocathodes or time projection chambers for tracking high fluxes of charged particles when the penetration of the avalanche ions back to the drift region may strongly disturb the detector operation. For example, in the case of photodetectors, the ions cause undesirable feedback preventing high gain operation necessary for single photoelectron detection. In the case of the time projection chambers, positive ions may disturb the uniformity of drift filed and thus affect the particle identification.

Development of Gating Foils To Inhibit Ion Feedback Using FPC Production Techniques

EPJ Web of Conferences ◽

10.1051/epjconf/201817402007 ◽

2018 ◽

Vol 174 ◽

pp. 02007 ◽

Cited By ~ 2

Author(s):

D. Arai ◽

K. Ikematsu ◽

A. Sugiyama ◽

M. Iwamura ◽

A. Koto ◽

...

Keyword(s):

Drift Region ◽

Electron Multiplier ◽

Gas Electron Multiplier ◽

Position Resolution ◽

Electron Transmission ◽

Printed Circuit ◽

Flexible Printed Circuit ◽

Production Techniques ◽

Time Projection ◽

Positive Ion

Positive ion feedback from a gas amplification device to the drift region of the Time Projection Chamber for the ILC can deteriorate the position resolution. In order to inhibit the feedback ions, MPGD-based gating foils having good electron transmission have been developed to be used instead of the conventional wire gate. The gating foil needs to control the electric field locally in opening or closing the gate. The gating foil with a GEM (gas electron multiplier)-like structure has larger holes and smaller thickness than standard GEMs for gas amplification. It is known that the foil transmits over 80 % of electrons and blocks ions almost completely. We have developed the gating foils using flexible printed circuit (FPC) production techniques including an improved single-mask process. In this paper, we report on the production technique of 335 μm pitch, 12.5 μm thick gating foil with 80 % transmittance of electrons in ILC conditions.

Space Charge Effects in Noble-Liquid Calorimeters and Time Projection Chambers

Instruments ◽

10.3390/instruments5010009 ◽

2021 ◽

Vol 5 (1) ◽

pp. 9

Author(s):

Sandro Palestini

Keyword(s):

Space Charge ◽

Scaling Laws ◽

Relative Size ◽

Design Solution ◽

Space Charge Effects ◽

Charge Effects ◽

Drift Length ◽

Calibration Methods ◽

The subject of space charge in ionization detectors is reviewed, showing how the observations and the formalism used to describe the effects have evolved, starting with applications to calorimeters and reaching recent, large time-projection chambers. General scaling laws, and different ways to present and model the effects are presented. The relations between space-charge effects and the boundary conditions imposed on the side faces of the detector are discussed, together with a design solution that mitigates some of the effects. The implications of the relative size of drift length and transverse detector size are illustrated. Calibration methods are briefly discussed.

Note on radiationless transitions involving three-body collisions

Mathematical Proceedings of the Cambridge Philosophical Society ◽

10.1017/s0305004100019186 ◽

1936 ◽

Vol 32 (3) ◽

pp. 482-485 ◽

Cited By ~ 2

Author(s):

R. A. Smith

Keyword(s):

Continuous Spectrum ◽

Negative Ions ◽

Bound State ◽

Excess Energy ◽

Negative Ion ◽

Positive Ions ◽

Continuous State ◽

Direct Formation ◽

Three Body ◽

Positive Ion

When an electron makes a transition from a continuous state to a bound state, for example in the case of neutralization of a positive ion or formation of a negative ion, its excess energy must be disposed of in some way. It is usually given off as radiation. In the case of neutralization of positive ions the radiation forms the well-known continuous spectrum. No such spectrum due to the direct formation of negative ions has, however, been observed. This process has been fully discussed in a recent paper by Massey and Smith. It is shown that in this case the spectrum would be difficult to observe.

Effect of Hadron Contamination on Dielectron Signal Reconstruction in Heavy Flavor Production Measurements

Advances in High Energy Physics ◽

10.1155/2015/385205 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Daniel Kikoła

Keyword(s):

Time Projection Chamber ◽

Signal Reconstruction ◽

Particle Identification ◽

Heavy Flavor ◽

Reconstruction Process ◽

Identification Process ◽

Heavy Flavor Production ◽

Dielectron signal reconstruction is an important tool for heavy flavor measurements because of its trigger feasibility and its relatively straightforward particle identification process. However, in the case of time projection chamber detectors, some hadron contamination is unavoidable, even if additional means are used to improve the particle identification process. In this paper, we investigate the effects of hadron (protons, pions, and kaons) contamination on the dielectron signal reconstruction process in the measurement ofJ/ψand electrons from heavy flavor hadron decays.

Gas-filled detectors

Particle Detectors ◽

10.1093/oso/9780198858362.003.0007 ◽

2020 ◽

pp. 171-254

Author(s):

Hermann Kolanoski ◽

Norbert Wermes

Keyword(s):

Magnetic Fields ◽

Particle Physics ◽

Parallel Plate ◽

Charged Particles ◽

Aging Effects ◽

Charge Generation ◽

Detector Performance ◽

Drift Chambers ◽

Detectors that record charged particles through their ionisation of gases are found in many experiments of nuclear and particle physics. By conversion of the charges created along a track into electrical signals, particle trajectories can be measured with these detectors in large volumes, also inside magnetic fields. The operation principles of gaseous detectors are explained, which include charge generation, gas amplification, operation modes and gas mixtures. Different detector types are described in some detail, starting with ionisation chambers without gas amplification, proceeding to those with gas amplification like spark and streamer chambers, parallel plate arrangements, multi-wire proportional chambers, chambers with microstructured electrodes, drift chambers, and ending with time-projection chambers. The chapter closes with an overview of aging effects in gaseous detectors which cause negative alterations of the detector performance.

First Demonstration of a Pixelated Charge Readout for Single-Phase Liquid Argon Time Projection Chambers

Instruments ◽

10.3390/instruments4010009 ◽

2020 ◽

Vol 4 (1) ◽

pp. 9 ◽

Cited By ~ 2

Author(s):

Jonathan Asaadi ◽

Martin Auger ◽

Antonio Ereditato ◽

Damian Goeldi ◽

Umut Kose ◽

...

Keyword(s):

Single Phase ◽

Signal To Noise Ratio ◽

Liquid Argon ◽

Track Reconstruction ◽

3D Tracking ◽

3D Space ◽

Event Reconstruction ◽

Phase Liquid ◽

Traditional charge readout technologies of single-phase Liquid Argon Time projection Chambers (LArTPCs) based on projective wire readout introduce intrinsic ambiguities in event reconstruction. Combined with the slow response inherent in LArTPC detectors, reconstruction ambiguities have limited their performance, until now. Here, we present a proof of principle of a pixelated charge readout that enables the full 3D tracking capabilities of LArTPCs. We characterize the signal-to-noise ratio of charge readout chain to be about 14, and demonstrate track reconstruction on 3D space points produced by the pixel readout. This pixelated charge readout makes LArTPCs a viable option for high-multiplicity environments.