Aluminum Thickness Tests

No Photon Physics

Varying Aluminum beamstop thickness

Tantalum thickness of 0.0508cm

All electron physics turned on

No photon physics turned on

Chamber and Tracker matter is vacuum

1 Radiation Length of Aluminum is 8.897cm

Aluminum Thickness	Photon Kinetic Energy Spectrum	Z Position of Photon Creation	Volume of Photon Creation
8.897cm
4.4485cm
2.22425cm
1.5875cm (5/8")
1.27cm (1/2")

Note: Volume 1 = Target, Volume 2 = Beamstop, Volume 3 = Tracker, Volume 4 = Chamber, Volume 5 = else

Conclusion

Without photon physics active and vacuum in the tracker and chamber, I cannot say whether electrons are making it though the target and beamstop.

Where are photons below 300 keV from?

These simulations have photon physics turned on

Physics	Photon Kinetic Energy Spectrum (Vacuum)	Photon Kinetic Energy Spectrum (Air)
Photon Physics Off
Photon Physics On

Beamstop, tracker, chamber, world all in vacuum. Target is Tantalum of 0.0508cm thickness

Beamstop & world in vacuum, tracker and chamber are air. Target is Tantalum of 0.0508cm thickness

As seen in the first image, if I remove the Aluminum beamstop, the <300KeV photon peak disappears. This leads me to believe that the it was electrons/photons interacting in the aluminum to create the lower energy photons.

In the second image, the low energy peak reappears, but is not the same as with the earlier simulations when the beamstop was aluminum. Looking at the volume in which photons were created, I can see that there are some interactions in the air. This could be pair production or electrons interacting directly with the air. These photons were not present in the simulation without air.

Photon Physics On

Varying Aluminum beamstop thickness

Tantalum thickness of 0.0508cm

All electron physics turned on

All photon physics turned on

Chamber and Tracker matter is vacuum

1 Radiation Length of Aluminum is 8.897cm

Aluminum Thickness	Photon Kinetic Energy Spectrum	Z Position of Photon Creation	Volume of Photon Creation
8.897cm
1.5875cm (5/8")
1.27cm (1/2")
4.4485cm
2.22425cm

Note: Volume 1 = Target, Volume 2 = Beamstop, Volume 3 = Tracker, Volume 4 = Chamber, Volume 5 = else

Conclusion

Why is tail 16 cm long?

I am going to rerun the 1 rad length simulation to see if i get the same result which will help me determine if i had an error in which matter i used in tracker/chamber, etc.

Photon Physics On with Air in Chamber and Tracker

Varying Aluminum beamstop thickness

Tantalum thickness of 0.0508cm

All electron physics turned on

All photon physics turned on

Chamber and Tracker matter is air (70% Nitrogen, 30% Oxygen)

1 Radiation Length of Aluminum is 8.897cm

Aluminum Thickness	Photon Kinetic Energy Spectrum	Z Position of Photon Creation	Volume of Photon Creation
8.897cm	200px	200px	200px
1.5875cm (5/8")	200px	200px	200px
1.27cm (1/2")	200px	200px	200px
4.4485cm	200px	200px	200px
2.22425cm	200px	200px	200px

Note: Volume 1 = Target, Volume 2 = Beamstop, Volume 3 = Tracker, Volume 4 = Chamber, Volume 5 = else

Conclusion

TriMev Simulations