The features of the processes of initiation and development of spark discharges in microstructural gas detectors of ionizing radiation in laboratory conditions and on charged-particle beams in ...accelerators are considered. Such aspects as the Raether charge limit, secondary electron emission, avalanche cross-overlap, positive ion feedback, explosive electron emission, cascading of detectors, and the charge density have been analyzed in detail. The better understanding of these effects will make it possible to make a further step in the development of new-type position-sensitive gas detectors.
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The causes of breakdowns in micro-pattern gas detectors have been investigated. According to the experimental data, this process is based on three independent sources: a corona discharge, a ...streamer discharge, and polarization of a dielectric when charges flow inside the detector. Several methods for increasing the resistance of devices of this type to damage from sparks are shown.
A Thick Gas Electronic Multiplier Razin, V. I.
Instruments and experimental techniques (New York),
04/2020, Letnik:
63, Številka:
2
Journal Article
Recenzirano
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The results of a study of the characteristics of a thick gas electron multiplier based on a fiberglass plate with a 0.8–2.0-mm-thick double-sided copper coating in which 1 mm holes were drilled at ...a spacing of 1.5 mm are presented. The gas filling of the multiplier is a mixture of Ar + 5% isobutane. The energy resolution for the
55
Fe line is 21%, the spatial resolution is 0.7 mm, the temporal resolution is better than 10 ns, and stable operation is provided up to an irradiation intensity of ~10
5
mm
–2
.
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The results obtained in the study of the avalanche process of electron multiplication in a thick gas amplifier of a new design are presented. The main feature of the device is the separation of the ...upper and lower parts of the amplifier by a gas gap with the preservation of the polyimide film as an insulator on the inner surface of the hole electrodes. The width of this gap can vary in the range of 0.1–1.0 mm, depending on the electrode size. With this separation, the surface leakage currents are absent between the electrodes and the charge is not induced on the inner surface of the gas-discharge gap. Due to this solution, it is possible to minimize the probability of both surface and volume streamer phenomena that turn into a Geiger or spark discharge. As a result, a pulse amplitude of a few volts was measured across a load of 50 Ω in a gas mixture of Ar + 20% CO
2
when the detector was irradiated with a
90
Sr β source.
Negative hydrogen ion sources are of great demand in modern physics as injectors into accelerators and drivers for neutral beam injectors for fusion devices. It has been shown earlier that the use of ...the gasdynamic ECR discharge provides the opportunity to extract up to 80 mA/cm2 of negative ion current density. We studied experimentally the volumetric negative hydrogen ion production and vacuum ultraviolet emission in a gasdynamic ECR discharge. The high-density plasma was sustained by the pulsed 37 GHz / 100 kW gyrotron radiation in a magnetic configuration consisting of two consecutive simple mirror traps. The future prospects of the volumetric H− source based on the gasdynamic ECR discharge related to the transition from pulsed to continuous operating mode with the use of an improved magnetic confinement system are discussed. Numerical simulation of the negative hydrogen ion beam extraction at the continuous operating mode facility was performed. Optimal configuration of the extraction electrodes and the electron damping magnets was found.
The results of the investigation of the dense ECR discharge hydrogen plasma flux formation in the magnetic field of a single solenoid are presented in this work. The transversal flux profile obtained ...at the optimal system parameters is shown. The possibility of the formation of homogeneous plasma fluxes with density of 750 mA/cm
2
and total current of 5 A is demonstrated. The results of the first experiments of the hydrogen ion beam extraction from the ECR discharge plasma in the single magnetic coil are presented. The record values of the ion current density higher than 1.5 A/cm
2
were obtained. The results of the research presented in this paper show the prospects of the proposed system for applications such as the neutral beam injector development for the plasma heating in the controlled fusion facilities.
This work is a continuation of the studies on the point neutron source development. In the neutron source scheme proposed, neutron emission occurs in a relatively small region (less than 1 mm) as a ...result of the D-D fusion reaction initiated when the focused deuterium ion beam hits the deuterium-loaded target. The main goal of the project is to develop a simple and compact device that can be used in the high-quality fast neutron radiography. In the scheme proposed, the ion beam is extracted from the dense ECR discharge plasma that is confined in the simple magnetic mirror trap. After upgrading the extraction system and the magnetic lens, the deuterium ion beam with a total current in the focal plane of up to 150 mA was obtained, which considerably exceeds the current obtained previously. The numerical simulations of the beam magnetic focusing were performed using the IBSimu code and the results were compared to the experimental data.
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