Related papers: GEM Operation in Negative Ion Drift Gas Mixtures
The dependence of the avalanche charge gain in Thick Gas Electron Multipliers (THGEM) on the purity of Ne, Ar and Xe filling gases was investigated. The gain, measured with alpha-particles in standard conditions (atmospheric pressure, room…
A comprehensive study, supported by systematic measurements and numerical computations, of the intrinsic limits of multi-GEM detectors when exposed to very high particle fluxes or operated at very large gains is presented. The observed…
We present avalanche gain and associated resolution measurements recorded with a $^4$He:CO$_2$ (70:30) gas mixture and pure SF$_6$, a Negative Ion (NI) gas. SF$_6$ is of particular interest to the directional dark matter detection…
Gas electron multiplier (GEM) is widely used in modern gas detectors of ionizing radiation in experiments on high-energy physics at accelerators and in other fields of science. Typically the GEM devices are based on a dielectric foil with…
A prototype Dual Gain Multilayer Thick Gas Electron Multilyer (DG-M-THGEM) with an active area of 10 cm $\times$ 10 cm was manufactured aiming at the production of a large-volume active-target time projection chamber which can work under…
The gas electron multiplier produced with the polyimide film 100 um thick. The maximum gas gain obtained with gas mixture Ar/CH4(91/9) was 5000. No decrease of gas gain with rates up to 2\cdot10^4 1/(mm^2 s) was observed. The possibility of…
For the successful design and operation of gas based particle detectors, one needs a good understanding of the drift properties of the deployed gas. This includes the drift velocity of electrons, their diffusion and the gas amplification in…
A prototype Gas Electron Multiplier (GEM) detector is under construction for medical imaging purposes. A single thick GEM of size 10x10 cm^2 is assembled inside a square shaped air-tight box which is made of Perspex glass. In order to…
The gain measurements of several 1 mm-thick, 10$\times$10 cm$^2$ Thick Gaseous Electron Multipliers (ThGEMs), operated in pure argon at 3.3 bar and room temperature are presented. Electrostatic simulations, performed with the COMSOL…
A new gas detector prototype for the upgrade of the focal plane detector of the MAGNEX large-acceptance magnetic spectrometer has been developed and tested in view of the NUMEN project. It has been designed to operate at low gas pressure…
Gas electron multipliers (GEMs) have been overcoated with a high resistivity 10e14 - 10e15 Ohms / square amorphous carbon layer. The coating avoids charging up of the holes and provides a constant gain immediately after switching on…
A quadruple GEM detector has been assembled in a standalone configuration and operated using Ar and CO$_2$ gas mixtures in proportions of 70:30 and 90:10. Detailed performance study of the detector has been made by using $^{106}$Ru-Rh…
Mechanisms of charging-up and charging-down of Gas Electron Multiplier (GEM) have been studied. Experimental investigations have been carried out on both dielectric polarization and radiation charging of GEMs. Environmental parameters, such…
The operation of a Micropattern Gaseous Detector (MPGD) comprising a cascade of two non-standard Gas Electron Multipliers (GEM) made from a 100 micrometer kapton foil was evaluated in pure krypton and in krypton-CO2 mixtures. The final…
As gaseous detectors are operated at high rates of primary ionisation, ions created in the detector have a considerable impact on the performance of the detector. The upgraded ALICE Time Projection Chamber (TPC) will operate during LHC…
We show that physics of multi-GEM structures is rather complex, regarding the number of phenomena affecting detector performance. The high-pressure operation in noble gases and the ion feedback are considered in more detail. It is proposed…
GEM are widely used as amplification stages in gaseous detectors exposed to high rates. The GEM consists of a polyimide foil which is coated by two thin copper layers. Charges collected into the holes or created during the amplification…
We present measurements of drift velocities and mobilities of some innovative negative ion gas mixtures at nearly atmospheric pressure based on SF$_{6}$ as electronegative capture agent and of pure SF$_{6}$ at various pressures, performed…
A variety of protective or reactive environmental gases have recently gained growing attention in laser-based metal additive manufacturing (AM) technologies due to their unique thermophysical properties and the potential improvements they…
We report the first observation of Negative Ion Drift (NID) at surface pressure of $900 \pm 7$ mbar at Laboratori Nazionali del Gran Sasso in a He:CF$_4$:SF$_6$ mixture using an optically read out Time Projection Chamber (TPC) within the…