MagBoltz calculating rates at high energies

[Crush]

Hi all,

I’m currently simulating multiple gains within an amplification gap over multiple field strengths. I find for larger field strengths, rarely an avalanche occurs where magboltz has to calculate the collision rate for high electron energies, an example of this is below.

------------ Processing Event: 686/999 ----------------
ne = 115078 ni = 115158 event 686
------------ Processing Event: 687/999 ----------------
ne = 81310 ni = 81369 event 687
------------ Processing Event: 688/999 ----------------
MediumMagboltz::GetElectronCollisionRate:
    Rate at 4.83721e+08 eV is not included in the current table.
    Increasing energy range to 5.07907e+08 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 5.41733e+08 eV is not included in the current table.
    Increasing energy range to 5.6882e+08 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 7.49183e+08 eV is not included in the current table.
    Increasing energy range to 7.86642e+08 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 1.81976e+09 eV is not included in the current table.
    Increasing energy range to 1.91075e+09 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 1.94509e+09 eV is not included in the current table.
    Increasing energy range to 2.04234e+09 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 2.64473e+09 eV is not included in the current table.
    Increasing energy range to 2.77697e+09 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 2.8605e+09 eV is not included in the current table.
    Increasing energy range to 3.00353e+09 eV.
ne = 63070853 ni = 63110436 event 688
------------ Processing Event: 689/999 ----------------
ne = 104048 ni = 104121 event 689

This often occurs every 1 in a couple hundred avalanches, but can take a significant amount of time to calculate and produces gains much higher than the others. Is there any way to possibly skip such events? This typically occurs as well when I use a mixture of Xenon/CO2 over the usual Argon/CO2.

[Piet]

Dear @Crush

I would find it quite exceptional you obtain electrons with energies of 500 MeV - few GeV in your avalanche. I presume you are using microscopic tracking? Can you tell us what gas mixture, what pressure and what electric field you use? Or do you use AvalancheMC and do you load gastables that you have calculated up to few hundred kV/cm?

Just to illustrate … immagine you simulate a very low pressure environment, and your electron freed in an ionization collision will start to accelerate in a, let’s say uniform 50kV/cm, electric field, and assume it would not lose any energy in a collision (very low pressure), after 1cm it would have gained 50keV of energy … you would need 10000cm (100m!) to arrive to 500MeV … very improbable.

I would have thought Magboltz would have complained at lower energies. Can you make a histogram of your electron energy in your avalanche, and make a zoom of the tails?

In AvalancheMicroscopic there is currently only a cut off for low energy (no further tracking if electron falls below the cut), not for high energy. You can think of implementing such a cut yourself and recompile the source code.
greets
Piet

[Crush]

Hi Piet,

I thought it was a little odd as well. The amplification gap is that of a micromegas, about 160um tall and a potential difference of 800V, so the electric field strength is about 50kv/cm in the gap. I’m currently using a mixture of Ar/CO2 at 90:10 at atmospheric pressure.

I am also tracking them using AvalancheMicroscopic, I’ll try and make a histogram.

Thanks,
Connor

[Crush]

Hi Piet,

Here is a histogram of the electron energies. I’m not sure the above happens, it seems that at maximum an electron should only have 800 eV as it travels the gap. I’m confused as to how such high energies are even possible.

Thanks,
Connor

[Piet]

Thanks @Crush for providing the plot. You can read there that your maximum electron energy in a collision is likely ~34eV, For sure you have zero electrons with > 100eV (you have zero overflow), this is very far away from the MeV-GeV electrons you were quoting above. Did you have the same warnings/log output of electrons at very high energy when you ran the simulation to create this histogram? Could you provide some minmal code that reproduces this issue?

If you’d like to debug, I would start having a look at where the GetElectronCollisionRate function is called:

• Source/AvalancheMicroscopic.cc · master · garfield / garfieldpp · GitLab
• Source/AvalancheMicroscopic.cc · master · garfield / garfieldpp · GitLab

It might be worthwile to investigate why you have a very high electron energy at the input here, also investigating whether this happens at a specific location (x,y,z) in your detector? Maybe your input electric field (calculated with FEM or BEM method) might give you in some areas an (unrealistic) very high field because of limited accuracy of the calculation. It would be good to have a look at your Efield and verify if there are no irregularies.

@Crush

I am also tracking them using AvalancheMicroscopic

Just to get the record straight, you only use avalanceMicroscopic and not AvalanceMC or DriftLineRKF, correct?

[Crush]

Hi Piet,

I might do some debugging to see as to why this is the case. In the meantime is there any way I could access these values, such that if an event occurred where this abnormal energy occurs I can break out of the avalanche and skip the event?

I was thinking that if there’s a way I can keep track of these energies and just skip the abnormal ones (as they’re a rare occurrence, often 1 every couple hundred).

Is there also any way I could print out the electrons position when GetElectronCollisionRate is called? I’m not sure how I would go about doing this.

Just for the record I’m tracking purely using AvalancheMicroscopic for the electrons, with fields calculated using COMSOL.

Thanks,

Connor

[Piet]

Dear @Crush

You might want to implement something along these lines in the function AvalancheMicroscopic::TransportElectron inside the file
Source/AvalancheMicroscopic.cc (lines 940-968)

while (isNullCollision) {
      // Sample the flight time.
      const double r = RndmUniformPos();
      dt += -log(r) * tLim;
      // Calculate the energy after the proposed step.
      en1 = std::max(en + (a1 + a2 * dt) * dt, Small);
      // Skip abnormally high electron energy (e.g. m_arbitraryCut = 100.e6 eV)
      if (en1 > m_arbitraryCut) {
          std::cout << "    Kinetic energy above my arbitrary transport cut: new Energy = "<<en1<<" eV.\n";
          std::cout << "    Electron coordinates (x,y,z,t) = "<<x<<","<<y<<","<<z<<","<<t<<"\n";
          std::cout << "    Electron energy and velocity (vx,vy,vz,E) = "<<vx<<","<<vy<<","<<vz<<","<<en<<"\n";
          std::cout << "    Electric field at (x,y,z) = "<<ex<<","<<ey<<","<<ez<<"\n";
          break;
       }
      // Get the real collision rate at the updated energy.
      const double fReal = medium->GetElectronCollisionRate(en1, band);

[Crush]

Hi Piet,

I was able to get the guys who operate our cluster computer system implement a version of AvalancheMicroscopic.cc with the code you suggested. They also went ahead and updated Garfield to the current master version (was 4.0).

The bug still persists but it now spits out some information which I’ve included in the table below.

------------ Processing Event: 28/999 ----------------
ne = 253644 ni = 253777 event 28
------------ Processing Event: 29/999 ----------------
MediumMagboltz::GetElectronCollisionRate:
    Rate at 7752.6 eV is not included in the current table.
    Increasing energy range to 8140.23 eV.
    Kinetic energy above my arbitrary transport cut: new Energy = 21282.4 eV.
    Electron coordinates (x,y,z,t) = 0.170178,0.168233,0.151258,25.6814
    Electron energy and velocity (vx,vy,vz,E) = 0.038987,0.00910617,-0.144873,6.42227
    Electric field at (x,y,z) = -4.09322e+06,-2.85201e+07,4.48628e+06
    Kinetic energy above my arbitrary transport cut: new Energy = 21274.3 eV.
    Electron coordinates (x,y,z,t) = 0.170081,0.167515,0.151346,25.6816
    Electron energy and velocity (vx,vy,vz,E) = -1.18055,-8.48821,1.19177,21282.4
    Electric field at (x,y,z) = 331.393,31071.9,-33287.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21253.4 eV.
    Electron coordinates (x,y,z,t) = 0.17005,0.167288,0.151378,25.6816
    Electron energy and velocity (vx,vy,vz,E) = -1.18054,-8.48675,1.19021,21274.3
    Electric field at (x,y,z) = 2286.91,17615.7,-32279.1
    Kinetic energy above my arbitrary transport cut: new Energy = 21254 eV.
    Electron coordinates (x,y,z,t) = 0.16992,0.166358,0.151508,25.6817
    Electron energy and velocity (vx,vy,vz,E) = -1.18009,-8.48335,1.18398,21253.4
    Electric field at (x,y,z) = -2591.94,-9180.55,-12586.1
    Kinetic energy above my arbitrary transport cut: new Energy = 21258.9 eV.
    Electron coordinates (x,y,z,t) = 0.169909,0.166276,0.15152,25.6818
    Electron energy and velocity (vx,vy,vz,E) = -1.18014,-8.4835,1.18377,21254
    Electric field at (x,y,z) = -2040.81,-11030.7,-15684.4
    Kinetic energy above my arbitrary transport cut: new Energy = 21265.2 eV.
    Electron coordinates (x,y,z,t) = 0.169834,0.165742,0.151594,25.6818
    Electron energy and velocity (vx,vy,vz,E) = -1.18036,-8.48473,1.18203,21258.9
    Electric field at (x,y,z) = 1572.34,-23163.2,-35997.3
    Kinetic energy above my arbitrary transport cut: new Energy = 21276.8 eV.
    Electron coordinates (x,y,z,t) = 0.169786,0.165391,0.151643,25.6819
    Electron energy and velocity (vx,vy,vz,E) = -1.18025,-8.48641,1.17941,21265.2
    Electric field at (x,y,z) = -4064.51,-34851.8,-47063.2
    Kinetic energy above my arbitrary transport cut: new Energy = 21290.7 eV.
    Electron coordinates (x,y,z,t) = 0.169729,0.164987,0.151699,25.6819
    Electron energy and velocity (vx,vy,vz,E) = -1.18059,-8.48933,1.17547,21276.8
    Electric field at (x,y,z) = 173.297,-32644.6,-61730.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21296.8 eV.
    Electron coordinates (x,y,z,t) = 0.169649,0.16441,0.151779,25.682
    Electron energy and velocity (vx,vy,vz,E) = -1.18057,-8.49323,1.1681,21290.7
    Electric field at (x,y,z) = 218.667,-29640.8,-71822.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21307.1 eV.
    Electron coordinates (x,y,z,t) = 0.169606,0.164103,0.151821,25.682
    Electron energy and velocity (vx,vy,vz,E) = -1.18055,-8.49512,1.16352,21296.8
    Electric field at (x,y,z) = 45.7935,-28564.3,-75667.2
    Kinetic energy above my arbitrary transport cut: new Energy = 21312.5 eV.
    Electron coordinates (x,y,z,t) = 0.169528,0.16354,0.151898,25.6821
    Electron energy and velocity (vx,vy,vz,E) = -1.18055,-8.49845,1.1547,21307.1
    Electric field at (x,y,z) = -550.172,-23860.7,-80398.4
    Kinetic energy above my arbitrary transport cut: new Energy = 21318.7 eV.
    Electron coordinates (x,y,z,t) = 0.169471,0.163125,0.151954,25.6821
    Electron energy and velocity (vx,vy,vz,E) = -1.1806,-8.5005,1.1478,21312.5
    Electric field at (x,y,z) = 164.428,-21022.3,-82168.7
    Kinetic energy above my arbitrary transport cut: new Energy = 21323.5 eV.
    Electron coordinates (x,y,z,t) = 0.169384,0.162502,0.152038,25.6822
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.5032,1.13721,21318.7
    Electric field at (x,y,z) = -39.136,-18130.8,-84059.4
    Kinetic energy above my arbitrary transport cut: new Energy = 21324 eV.
    Electron coordinates (x,y,z,t) = 0.169288,0.16181,0.15213,25.6823
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.5058,1.12519,21323.5
    Electric field at (x,y,z) = 7.76145,-15642.4,-85172.7
    Kinetic energy above my arbitrary transport cut: new Energy = 21324.4 eV.
    Electron coordinates (x,y,z,t) = 0.169272,0.161695,0.152145,25.6823
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.50617,1.12316,21324
    Electric field at (x,y,z) = 7.40774,-15296.3,-85312.1
    Kinetic energy above my arbitrary transport cut: new Energy = 21325.3 eV.
    Electron coordinates (x,y,z,t) = 0.169258,0.161594,0.152158,25.6823
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.50649,1.12138,21324.4
    Electric field at (x,y,z) = 4.49555,-14999.2,-85432.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21326.5 eV.
    Electron coordinates (x,y,z,t) = 0.169226,0.161361,0.152189,25.6823
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.50721,1.11726,21325.3
    Electric field at (x,y,z) = -11.0965,-14330.3,-85708.5
    Kinetic energy above my arbitrary transport cut: new Energy = 21327.2 eV.
    Electron coordinates (x,y,z,t) = 0.169171,0.160965,0.152241,25.6824
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.50839,1.11024,21326.5
    Electric field at (x,y,z) = 19.609,-13191.2,-86306.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21327.6 eV.
    Electron coordinates (x,y,z,t) = 0.169126,0.160643,0.152283,25.6824
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.50926,1.10449,21327.2
    Electric field at (x,y,z) = 18.741,-12425.2,-86753.7
    Kinetic energy above my arbitrary transport cut: new Energy = 21327.8 eV.
    Electron coordinates (x,y,z,t) = 0.169074,0.16027,0.152331,25.6825
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.51022,1.09782,21327.6
    Electric field at (x,y,z) = 10.5689,-11744.4,-87201.1
    Kinetic energy above my arbitrary transport cut: new Energy = 21327.6 eV.
    Electron coordinates (x,y,z,t) = 0.169023,0.1599,0.152379,25.6825
    Electron energy and velocity (vx,vy,vz,E) = -1.18058,-8.51112,1.09115,21327.8
    Electric field at (x,y,z) = 40.5245,-10935.4,-87526
    Kinetic energy above my arbitrary transport cut: new Energy = 21327.2 eV.
    Electron coordinates (x,y,z,t) = 0.168686,0.157473,0.152683,25.6828
    Electron energy and velocity (vx,vy,vz,E) = -1.18056,-8.5166,1.04726,21327.6
    Electric field at (x,y,z) = 60.321,-7149.46,-89533.5
    Kinetic energy above my arbitrary transport cut: new Energy = 21326.7 eV.
    Electron coordinates (x,y,z,t) = 0.168672,0.157366,0.152696,25.6828
    Electron energy and velocity (vx,vy,vz,E) = -1.18056,-8.51676,1.04529,21327.2
    Electric field at (x,y,z) = 60.6764,-7010.05,-89612.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21322.8 eV.
    Electron coordinates (x,y,z,t) = 0.168653,0.157233,0.152713,25.6828
    Electron energy and velocity (vx,vy,vz,E) = -1.18055,-8.51695,1.04282,21326.7
    Electric field at (x,y,z) = 61.139,-6836.6,-89711.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21321.7 eV.
    Electron coordinates (x,y,z,t) = 0.168519,0.156261,0.152831,25.6829
    Electron energy and velocity (vx,vy,vz,E) = -1.18054,-8.51832,1.02482,21322.8
    Electric field at (x,y,z) = 71.4527,-5752.6,-90443.1
    Kinetic energy above my arbitrary transport cut: new Energy = 21320.8 eV.
    Electron coordinates (x,y,z,t) = 0.16849,0.156058,0.152855,25.683
    Electron energy and velocity (vx,vy,vz,E) = -1.18054,-8.51857,1.02103,21321.7
    Electric field at (x,y,z) = 72.4875,-5531.67,-90544.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21304 eV.
    Electron coordinates (x,y,z,t) = 0.168466,0.155883,0.152876,25.683
    Electron energy and velocity (vx,vy,vz,E) = -1.18054,-8.51877,1.01775,21320.8
    Electric field at (x,y,z) = 73.4132,-5341.46,-90632
    Kinetic energy above my arbitrary transport cut: new Energy = 21296.1 eV.
    Electron coordinates (x,y,z,t) = 0.168017,0.152642,0.153252,25.6834
    Electron energy and velocity (vx,vy,vz,E) = -1.18049,-8.52234,0.957128,21304
    Electric field at (x,y,z) = 127.782,-2435.07,-91640.4
    Kinetic energy above my arbitrary transport cut: new Energy = 21294.3 eV.
    Electron coordinates (x,y,z,t) = 0.167876,0.15162,0.153365,25.6835
    Electron energy and velocity (vx,vy,vz,E) = -1.18046,-8.52285,0.937788,21296.1
    Electric field at (x,y,z) = 116.871,-1538.03,-91543.3
    Kinetic energy above my arbitrary transport cut: new Energy = 21289.8 eV.
    Electron coordinates (x,y,z,t) = 0.167847,0.151414,0.153388,25.6835
    Electron energy and velocity (vx,vy,vz,E) = -1.18046,-8.52292,0.933909,21294.3
    Electric field at (x,y,z) = 109.467,-1342.97,-91521
    Kinetic energy above my arbitrary transport cut: new Energy = 21283.6 eV.
    Electron coordinates (x,y,z,t) = 0.167775,0.150896,0.153444,25.6836
    Electron energy and velocity (vx,vy,vz,E) = -1.18044,-8.52306,0.924112,21289.8
    Electric field at (x,y,z) = 99.4974,-867.997,-91413.2
    Kinetic energy above my arbitrary transport cut: new Energy = 21277.9 eV.
    Electron coordinates (x,y,z,t) = 0.167679,0.150199,0.153519,25.6836
    Electron energy and velocity (vx,vy,vz,E) = -1.18043,-8.52319,0.910975,21283.6
    Electric field at (x,y,z) = 134.378,-286.334,-91229.3
    Kinetic energy above my arbitrary transport cut: new Energy = 21265.4 eV.
    Electron coordinates (x,y,z,t) = 0.167596,0.149599,0.153583,25.6837
    Electron energy and velocity (vx,vy,vz,E) = -1.18041,-8.52322,0.899684,21277.9
    Electric field at (x,y,z) = 155.363,297.446,-91095.9
    Kinetic energy above my arbitrary transport cut: new Energy = 21264.8 eV.
    Electron coordinates (x,y,z,t) = 0.167418,0.14832,0.153716,25.6839
    Electron energy and velocity (vx,vy,vz,E) = -1.18037,-8.52314,0.875631,21265.4
    Electric field at (x,y,z) = 262.31,1515.95,-90995.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21252.5 eV.
    Electron coordinates (x,y,z,t) = 0.167411,0.148269,0.153722,25.6839
    Electron energy and velocity (vx,vy,vz,E) = -1.18037,-8.52313,0.874671,21264.8
    Electric field at (x,y,z) = 264.709,1562.55,-90992.2
    Kinetic energy above my arbitrary transport cut: new Energy = 21231.6 eV.
    Electron coordinates (x,y,z,t) = 0.167253,0.147126,0.153837,25.684
    Electron energy and velocity (vx,vy,vz,E) = -1.18031,-8.52276,0.853214,21252.5
    Electric field at (x,y,z) = 311.777,2593.72,-90895.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21230.2 eV.
    Electron coordinates (x,y,z,t) = 0.167003,0.145318,0.154015,25.6842
    Electron energy and velocity (vx,vy,vz,E) = -1.18019,-8.52179,0.819292,21231.6
    Electric field at (x,y,z) = 250.854,3865.79,-90601.5
    Kinetic energy above my arbitrary transport cut: new Energy = 21224.2 eV.
    Electron coordinates (x,y,z,t) = 0.166988,0.14521,0.154025,25.6842
    Electron energy and velocity (vx,vy,vz,E) = -1.18018,-8.5217,0.817269,21230.2
    Electric field at (x,y,z) = 285.186,3977.39,-90523.3
    Kinetic energy above my arbitrary transport cut: new Energy = 21221.5 eV.
    Electron coordinates (x,y,z,t) = 0.166922,0.144737,0.15407,25.6843
    Electron energy and velocity (vx,vy,vz,E) = -1.18016,-8.52132,0.808447,21224.2
    Electric field at (x,y,z) = 301.575,4335.68,-90281.8
    Kinetic energy above my arbitrary transport cut: new Energy = 21218.5 eV.
    Electron coordinates (x,y,z,t) = 0.166893,0.144523,0.154091,25.6843
    Electron energy and velocity (vx,vy,vz,E) = -1.18014,-8.52113,0.804449,21221.5
    Electric field at (x,y,z) = 305.164,4367.11,-90120.7

There was also a seperate event with similar occurences,

------------ Processing Event: 9/999 ----------------
MediumMagboltz::GetElectronCollisionRate:
    Rate at 264.781 eV is not included in the current table.
    Increasing energy range to 278.021 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 472.515 eV is not included in the current table.
    Increasing energy range to 496.141 eV.
MediumMagboltz::GetElectronCollisionRate:
    Rate at 1450.5 eV is not included in the current table.
    Increasing energy range to 1523.02 eV.
    Kinetic energy above my arbitrary transport cut: new Energy = 11952.3 eV.
    Electron coordinates (x,y,z,t) = 0.230158,0.201613,0.151606,24.3665
    Electron energy and velocity (vx,vy,vz,E) = 0.095571,-0.140273,-0.111639,11.7333
    Electric field at (x,y,z) = -776403,-2.28315e+07,6.07216e+06
    Kinetic energy above my arbitrary transport cut: new Energy = 11946.2 eV.
    Electron coordinates (x,y,z,t) = 0.230156,0.201119,0.151715,24.3667
    Electron energy and velocity (vx,vy,vz,E) = -0.113922,-6.30079,1.52678,11952.3
    Electric field at (x,y,z) = -1746.98,28161.9,-49668.6
    Kinetic energy above my arbitrary transport cut: new Energy = 11938.2 eV.
    Electron coordinates (x,y,z,t) = 0.230154,0.200966,0.151752,24.3667
    Electron energy and velocity (vx,vy,vz,E) = -0.113997,-6.29959,1.52466,11946.2
    Electric field at (x,y,z) = -2084.8,26574.5,-47106.2
    Kinetic energy above my arbitrary transport cut: new Energy = 11928 eV.
    Electron coordinates (x,y,z,t) = 0.23015,0.200755,0.151803,24.3667
    Electron energy and velocity (vx,vy,vz,E) = -0.114119,-6.29802,1.52188,11938.2
    Electric field at (x,y,z) = -144.169,18331.4,-40826.5
    Kinetic energy above my arbitrary transport cut: new Energy = 11924.3 eV.
    Electron coordinates (x,y,z,t) = 0.230143,0.200394,0.15189,24.3668
    Electron energy and velocity (vx,vy,vz,E) = -0.114134,-6.29618,1.51777,11928
    Electric field at (x,y,z) = -437.065,10498.2,-39921.4
    Kinetic energy above my arbitrary transport cut: new Energy = 11923.9 eV.
    Electron coordinates (x,y,z,t) = 0.23014,0.20021,0.151934,24.3668
    Electron energy and velocity (vx,vy,vz,E) = -0.114156,-6.29564,1.51572,11924.3
    Electric field at (x,y,z) = -893.921,4144.25,-40514.1
    Kinetic energy above my arbitrary transport cut: new Energy = 11923.9 eV.
    Electron coordinates (x,y,z,t) = 0.230139,0.200182,0.151941,24.3668
    Electron energy and velocity (vx,vy,vz,E) = -0.114164,-6.2956,1.5154,11923.9
    Electric field at (x,y,z) = -964.036,3169.2,-40605
    Kinetic energy above my arbitrary transport cut: new Energy = 11917.6 eV.
    Electron coordinates (x,y,z,t) = 0.230139,0.20018,0.151942,24.3668
    Electron energy and velocity (vx,vy,vz,E) = -0.114164,-6.2956,1.51538,11923.9
    Electric field at (x,y,z) = -967.652,3118.91,-40609.7
    Kinetic energy above my arbitrary transport cut: new Energy = 11917.2 eV.
    Electron coordinates (x,y,z,t) = 0.230131,0.199692,0.152059,24.3669
    Electron energy and velocity (vx,vy,vz,E) = -0.114296,-6.29518,1.50983,11917.6
    Electric field at (x,y,z) = -287.179,-7195.19,-44166.7
    Kinetic energy above my arbitrary transport cut: new Energy = 11917 eV.
    Electron coordinates (x,y,z,t) = 0.230128,0.199552,0.152092,24.3669
    Electron energy and velocity (vx,vy,vz,E) = -0.114307,-6.29546,1.50811,11917.2
    Electric field at (x,y,z) = 53.1517,-9344.4,-45317.8
    Kinetic energy above my arbitrary transport cut: new Energy = 11917 eV.
    Electron coordinates (x,y,z,t) = 0.230126,0.199442,0.152119,24.367
    Electron energy and velocity (vx,vy,vz,E) = -0.114306,-6.29574,1.50672,11917
    Electric field at (x,y,z) = 322.331,-11044.4,-46227.9
    Kinetic energy above my arbitrary transport cut: new Energy = 11917 eV.
    Electron coordinates (x,y,z,t) = 0.230124,0.199324,0.152147,24.367
    Electron energy and velocity (vx,vy,vz,E) = -0.114295,-6.29611,1.5052,11917
    Electric field at (x,y,z) = 609.106,-12855.7,-47197.1
    Kinetic energy above my arbitrary transport cut: new Energy = 11918.4 eV.
    Electron coordinates (x,y,z,t) = 0.230123,0.199289,0.152155,24.367
    Electron energy and velocity (vx,vy,vz,E) = -0.114289,-6.29624,1.50473,11917
    Electric field at (x,y,z) = 695.877,-13403.8,-47490.2

This was for the 50-60kV/cm field strength in the gap, as pictured above.
I do see that at some points there’s an electric field strength that goes above 4.e6 which seems odd, as the image suggests that there’s nothing above 1.5e5 V/cm.

Also oddly enough, the field seems to take negative values at various of these points (where I’m sure they should be positive). It also seems that these extremely high field values occure at similar z values, around 0.151cm.

Thanks,
Connor

[hschindl]

Hi @Crush, thanks for the debugging! This seems to suggest that there might be an issue with the field map. Can you check the range of potentials? Also could you make a plot of the aspect ratios and element volumes (just need to call the function Check() of ComponentComsol)?

[Crush]

Hi Schindl,

I get the following as an output, I also got the message that there are 89 elements with zero volume, along with,
Smallest Largest
Aspect ratios: 1.00402589 4.65602439
Volumes [mm3]: 0.00000000 0.00138291

Thanks,
Connor

I also confirmed that the largest voltage in the field map is accurate to what was intended, 800v applied on the anode strips and nothing above 800.