Multidrift module simulation

The main results of simulating multidrift module (MDM) characteristics are presented. Using the GARFIELD program, the electric field equipotential lines for a seven-cell structure were simulated. We atempted to calculate the gas multiplication factor for the MDM cell filled with DME assuming various types of Townsend coefficient dependences on the field intensity E. The best agreement with the experimental data was obtained assuming that α/p is proportional to (E/p)2. The x(t)-relation for the MDM cell was calculated with the help of the GARFIELD procedure for electron arrival time distribution calculations for a track. Good agreement with the experimental curve was obtained under the condition that for E>20 kV/cm the electron drift velocity in DME is proportional to (E/p)1/2. On the basis of the electron arrival time distributions the coordinate accuracy was calculated for a single MDM cell. The results obtained completely agree with the experimental data. (orig.)