Date of Graduation

8-2012

Document Type

Thesis

Degree Name

Master of Science in Physics (MS)

Degree Level

Graduate

Department

Physics

Advisor/Mentor

Reeta Vyas

Committee Member

Hameed Naseem

Second Committee Member

William Oliver III

Third Committee Member

Surendra Singh

Fourth Committee Member

Archana Sharma

Keywords

Pure sciences, Charging up, GEM, Gsin, Penning parameter, Polyimide conductivity, Simulation

Abstract

Gas Electron Multiplier (GEM) is a gaseous detector used in particle detection and is

known for its high rate capability. Ever since its invention in 1997, GEM was applied in

many areas and recently has been proposed to be installed in the CMS high η regions for

upgrade at LHC, CERN. A complete understanding of the working and gain behaviour does

not exist. GEM gain is influenced by charging up and this has been variedly interpreted

in literature lacking consensus. I have attempted in this work through simulations and

measurements to achieve a better understanding of single GEM gain and how it is affected by

various factors. Specific experimental methods which evolved with subsequent measurements

were employed to systematically study the charging up effect. Information from simulations

was applied to characterize measurements thereby enabling the development of a model for

charging up. Conductivity mechanism of the dielectric used in GEM was analyzed and the

resistivity measured. Gain free of charging up effects was measured and this is appropriate

for comparison with simulations

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