| Message: why polarization vector is not perpendicular to momentum ? | Not Logged In (login) |
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Hi,
Thanks Peter for your nice guiding firstly! When I run the Pol01 (extented/polarisation/Pol01) program, the problem that has been showed in "Paticle" Category in this forum happens again. Changes in the Pol01: (1) the material of Box was changed to be G4_PLASTIC_SC_VINYLTOLUENE (2) boxSizeZ = 50. *mm (3) 122.1 keV gamma rays Results:
>> gun/polarization 1 0 0
>> tracking/verbose 3
>> run/beamOn 1
...
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StepPoint Information PreStep PostStep
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Position - x (mm) : 0 0
Position - y (mm) : 0 0
Position - z (mm) : -25 13.0631383823411
Global Time (ns) : 0.08339102379953801 0.2103559869486146
Local Time (ns) : 0.08339102379953801 0.2103559869486146
Proper Time (ns) : 0 0
Momentum Direct - x : 0 -0.1869627173785501
Momentum Direct - y : 0 -0.9193385470136727
Momentum Direct - z : 1 0.3462103093283293
Momentum - x (MeV/c): 0-0.01974379366979246
Momentum - y (MeV/c): 0-0.09708476021009742
Momentum - z (MeV/c): 0.1221 0.03656079142181843
Total Energy (MeV) : 0.1221 0.1056028386120239
Kinetic Energy (MeV): 0.1221 0.1056028386120239
Velocity (mm/ns) : 299.792458 299.792458
Volume Name : G4_PLASTIC_SC_VINYLTOLUENEG4_PLASTIC_SC_VINYLTOLU ENE
Safety (mm) : 0 11.9368616176589
Polarization - x : 1 -0.9794236864290253
Polarization - y : 0 -0.1386048373629611
Polarization - Z : 0 0
Weight : 1 1
Step Status : Geom Limit PostStep Proc
Process defined Step: Transportation pol-compt
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Questions: According to those results (assumed to be calculated in the world frame), in the poststep, the angle between momentum and polar vector of gamma ray is about 72 degree. Why did they not perpendicular to each other? What's wrong? Thanks for your help! Best Regards! zhangyf
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