ok dear i’ll see density issue too.
can you tell me how you have calculated the density of tetrafluoroethane and Atmospheric temp. pressure?
one more thing dear i haven’t use the above density figure or something just last night changes and it still running for 150 events. and showing gain = 0 avalanche size = 0 is it ok or any issue what you think?
Summing up the atomic mass numbers gives
2 x 12 (C) + 2 x 1 (H) + 4 x 19 (F) = 102
So one molecule has a mass of 102 u (where u = 1.660538782e-24 g is the atomic mass unit).
An ideal gas at standard temperature (273.15 K) and pressure has a number density N = 2.6867774e19 cm-3 (Loschmidt constant), so you get a mass density of
102 u * N = 0.00455… g / cm3
To scale to 20° C, multiply by (273.15 / 293.15), which gives 0.00424… g / cm3.
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There is no way for me to tell from this screenshot why the program gets stuck or is slow, which if I understood correctly is the problem, no? That’s why I asked you for the gas file you are using such that I can try to reproduce the issue myself.
yes dear i can understand i’ll try to send file to you again. that will be tetrafluoroethane 100%.TETRAFLUOROETHANE.txt (13.7 KB) this is the gas file according to which i have made changes this far in the geant4garfieldInterface/src/detector construction and garfieldPhysics.cc
thank dear for explanation.
hi, dear i have done the upper calculation as you explained but my answer is coming 2.866 g / cm3. why is it so?
Thanks for the gas file. As you can see from the attached plot, the attachment coefficient (η) is significantly larger than the Townsend coefficient (α) in the electric field range relevant for the electron drift towards the wire. So the electrons will indeed be attached before they can start an avalanche.
I noticed that the gas file was calculated for a pressure of 2280 Torr (three times the atmospheric pressure). I assume this was a mistake and you meant to calculate it for atmospheric pressure? If yes, you should re-run Magboltz to generate a new gas file.
I’ve also attached a small program that makes this plot and also calculates the average gain in the drift tube geometry you are simulating.
AlphaEta.pdf (23.5 KB) plot.C (1.3 KB)
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102 * 1.660538782e-24 * 2.6867774e19 = 0.004…
ok dear i’ll change generate gas files for atmospheric pressure. but sorry to say one more thing the files you sent me aplha Eta and plot.c i have to replace somewhere in the garfield or just and explanation?
The plot (pdf file) is just to explain why you get zero electrons in your simulation. And the program plot.C is just in case you want to make this plot yourself.
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thank you dear… i’m generating now the new gas files just by using atmospheric pressure. not 3 times. 
hi hschindl!. i have generated the gas files on the atmospheric pressure changing them from 3 times which was previous set. and again put the gas file in the geant4garfieldinterface example. and starts 1000 events. and also using the value of density as you told to find it out. but here it is still giving some error. is this ok? let the program completed it ?
one more thing i have started the simulation work after putting gas file in the geant4garfieldInterface at night and now after couple of hours its just 3-4 events done. is it ok? it takes time like this or something occuring bad?
i have also changed the units of gas tetrtafluoroethane in the detector construction file from mg / cm3 to g/ cm3.
No, that doesn’t look good. It seems like the gas file was not loaded.
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dear today i have changed the gas file and put the mixture of C2H2F4, iC4H10, SF6 make changes according to it in the garfielddetectorconstruction and garfieldphysics.cc see here but in last pic you can see it is giving some error can you help in this regard too.
The error message is quite clear. There is no material called C2H2F4_iC4H10_SF6. You need to define one in GarfieldDetectorConstruction::DefineMaterials().