Speakers
Description
GEM based detectors are now almost an integral part of high energy physics (HEP) experiments. Most of the experiments have, however, used triple GEM detectors. A quadruple GEM detector specially designed for low ion back flow will be used for the readout of the upgraded TPC in ALICE experiment. We present the study of a triple and a quadruple GEM detector and compare their performances in order to understand the usefulness of increasing the number of GEM foils and obtain better operating parameters to suit the requirements of HEP experiments.
The detectors have been assembled in standalone configuration and tested with $^{55}$Fe X-ray and $^{106}$Ru-Rh $\beta$-source using Ar/CO$_2$ gas mixtures with 90:10 and 70:30 proportions. Effective gain and energy resolution have been measured using $^{55}$Fe source. The efficiency is measured using the $^{106}$Ru-Rh $\beta$-source and a coincidence setup consisting of three scintillators. In addition, the uniformity of the gain and energy resolution of the GEM detectors have been investigated by dividing the active area in 7$\times$7 zones.
It was found that quadruple GEM detector operates at less voltage across individual GEM foil ($\Delta$V$_{GEM}$) compared to the triple GEM detector. It is also found that the energy resolution of the detector deteriorates in case of quadruple GEM detector. Time resolution of the detectors is also measured and the obtained value is $\sim$10 – 13 ns at the operating voltage.
We have studied the electron transparency of the quadruple GEM detector with different drift field configurations for understanding the charge transfer phenomena through the GEM foils. An optimum drift field for the maximum transparency is obtained from the results. Garfield simulation studies are in progress for understanding the working phenomena and results of the test.
| Content type | Experiment |
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| Centralised submission by Collaboration | Presenter name already specified |
