CMS GEM Simulation through Garfield++

Disclamer : Preliminary version of the Twiki page, written by Geoffrey Mullier.

Objective

Provide detailed simulation and description of the GEM signals through simulation and comparison to real signals from prototypes. The simulation includes both signal and position of charges in order to retrieve information both on timing and cluster size distribution. The comprehension of raw signals is important to deliver quality signal simulation to get the best information possible on the timing resolution achievable depending on both the electronics and the timing method used. The work also include general gas characteristic simulations as input for the FastSim project.

Logistics

Currently two independent groups are working on Garfield++ simulations, one at ULB and one at Texas A&M University with two main contributors

• Geoffrey Mullier (ULB)
• Yasser Assran (Texas A&M University)

Current Status

Here you will find a brief status of simulations from both groups.

ULB (Geoffrey Mullier)

More coming soon.

Singal simulations:

Currently the modelisation of the signals in Ar CO2 (70:30) and Ar CO2 CF4 (45:15:40) has been made for the simple case of an infinite electrodes and the signals have already been analysed for 1 GeV muons perpendicular to the detector. Two methods have been used to evaluate the time resorption namely ToT(Time over Treshold) and CFD (Constant Fraction Discriminator)

The multiple electrode case is being investigated and simulated with help of the FastSim with a basic cell containing 5 electrodes. Early results are already there but a deeper analysis is required.

(Graphs coming soon)

Gas Characteristics simulations

Currently the Characteristics of three different gaz mixtures have been considered and studied through Magbotlz incorporated into Garfield++

Ar CO2 (70:30), Ar CO2 CF4 (45:40:15) and Ar CO2 CF4 (45:15:40) for their diffusion coefficient, longitudinal and transversal (Ar CO2 (70:30) Ar CO2 CF4 (45:40:15) Ar CO2 CF4 (45:15:40)) , drift velocity (Ar CO2 (70:30) Ar CO2 CF4 (45:40:15) Ar CO2 CF4 (45:15:40)), attachment coefficients (Ar CO2 (70:30) Ar CO2 CF4 (45:40:15) Ar CO2 CF4 (45:15:40)) and number of cluster along a track for 1GeV Muons.

To do list :

• Simulation of signals of Triple GEMs detector in a magnetic field.
• Simulation of muons non perpendicular to the detector.

Texas A&M University (Yasser Assran)

Coming Soon