The integrated charge is 0

[newconcept1979]

The integrated charge is computed using the gas with pressure of 76. Torr, when changing the charge from negative to positive and filling a TH1D class object, the result is:

but when changing the pressure to 760. Torr, the result is:

why the integrated charge is 0 with lower pressure?

the related files are attached.

Ar_90_ch4_10_0.1bar.gas.txt (75.5 KB)

DriftLineRKF.C (2.7 KB)

[newconcept1979]

sorry, the first figure is wrong, here is the right one:

[bellenot]

I think @hschindl can help

[newconcept1979]

when using AvalancheMicroscopic class, the result is:

this is weird, what is the possible reason?

[hschindl]

Hi,
thanks for your message! I tried to reproduce the issue with a slightly modified version of your program which you’ll find attached (rkf.C). The total induced charge does change when changing the pressure to 760 Torr but I don’t get zero. How did you change the pressure in your application? Did you create a new gas file or did you use the one for 76 Torr and changed the pressure?

[newconcept1979]

@hschindl, thanks for your reply! but something should be clarified.

1. where is the file of “rkf.C“;
2. when using DriftLineRKF class and the gas pressure is 0.1 bar, the total charge is 0, it is nothing about 1 bar of the the gas pressure;
3. in my application, the gas file is used and the pressure is 0.1 bar. so the total charge is 0 when using DriftLineRKF class and the gas pressure is 0.1 bar, is that nornal?

[hschindl]

Sorry, forgot to attach the file!

rkf.C (1.3 KB)

[newconcept1979]

@hschindl, thanks for your reply!

[newconcept1979]

the potential is changed to 5000V, all the calculations use the gas file(all calculated by MediumMagboltz class), why the total charge decrease with the gas pressure increase?

[hschindl]

The Townsend coefficient decreases with increasing pressure.

[newconcept1979]

@hschindl, thanks for your reply!