Difference between revisions of "LaserComptonScat"

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   |'''BDSIM, <math>E\gamma</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
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   |'''BDSIM, <math>\lambda_laser</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:BDSIM_At_20MeVelectron_2.326eVphoton_10-26-08a.jpg | 400 px]] || [[Image:BDSIM_At_20MeVelectron_2.326eVphoton_10-24-08b.jpg | 400 px]]
 
   |[[Image:BDSIM_At_20MeVelectron_2.326eVphoton_10-26-08a.jpg | 400 px]] || [[Image:BDSIM_At_20MeVelectron_2.326eVphoton_10-24-08b.jpg | 400 px]]
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   |'''BDSIM, <math>E\gamma</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
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   |'''BDSIM, <math>\lambda_laser</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:BDSIM_At_20MeVelectron_1eVphoton_10-26-08a.jpg | 400 px]] || [[Image:BDSIM_At_20MeVelectron_1eVphoton_10-24-08b.jpg | 400 px]]
 
   |[[Image:BDSIM_At_20MeVelectron_1eVphoton_10-26-08a.jpg | 400 px]] || [[Image:BDSIM_At_20MeVelectron_1eVphoton_10-24-08b.jpg | 400 px]]
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   |'''Geant4_lowEnCompton, <math>E\gamma</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
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   |'''Geant4_lowEnCompton, <math>\lambda_laser</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08a.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08b.jpg | 400 px]]
 
   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08a.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08b.jpg | 400 px]]
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   |'''Geant4_lowEnCompton, <math>E\gamma</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
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   |'''Geant4_lowEnCompton, <math>\lambda_laser</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08a.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08b.jpg | 400 px]]
 
   |[[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08a.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08b.jpg | 400 px]]
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   |'''Geant4_Compton, <math>E\gamma</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
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   |'''Geant4_Compton, <math>\lambda_laser</math>:266nm (for 532nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08c.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08d.jpg | 400 px]]
 
   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08c.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08d.jpg | 400 px]]
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   |'''Geant4_Compton, <math>E\gamma</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
+
   |'''Geant4_Compton, <math>\lambda_laser</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''|| '''Angular dependence (Head-on collision)'''
 
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   |[[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08c.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08d.jpg | 400 px]]
 
   |[[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08c.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_1eVphoton_10-30-08d.jpg | 400 px]]
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   |'''Geant4 <math>E\gamma</math>:266nm (for 532 nm laser), <math>E_e</math>=20 MeV'''|| '''Geant4 <math>E\gamma</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''
+
   |'''Geant4 <math>\lambda_laser</math>:266nm (for 532 nm laser), <math>E_e</math>=20 MeV'''|| '''Geant4 <math>\lambda_laser</math>:532nm (for 1064nm laser), <math>E_e</math>=20 MeV'''
 
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   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08e.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08f.jpg | 400 px]]
 
   |[[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08e.jpg | 400 px]] || [[Image:Geant4_At_20MeVelectron_2.326eVphoton_10-30-08f.jpg | 400 px]]

Revision as of 03:17, 31 October 2008

Notes on Syed's GEANT4 project for Laser Compton Scattering at the IAC

2/7/08

Step 1: Configure Event generator in which electron parameters can be changes. Move the source left and right of the center. Change is momentum direction; going left and going right.

Step 2: comment out electron and add gamma. get it to move in the same way.

Step 3: turn them both on

Step 4: if fail then find references on event Generator with 2 intersecting beams, perhaps ILC, LHC or BaBar has one.

2/14/08

Problem last week was due to editing the wrong file.

We now have a event generator which starts an electron and a photon moving toward eachother.

We see and event when the photon energy is 500 keV and only the compton process is turned on.

FirstComptonEvent 2-14-08.jpg

Next step:

1.) edit the Stepping Verbose so only a Compton event is printed out

2.) add an event counter so we know how many beam triggers are done to get the event( edit SteppingVerbose.h, add a global variable to the class definition)

output : event number, Photon position, Electron position, Photon and Electron initial and final momentum.

3.) Compare output with BDSIM at 500 keV

4.) Insert new physics process for Low Energy Compton

2/28/08

1.) edit the Stepping Verbose so only a Compton event is printed out (done)

2.) add an event counter so we know how many beam triggers are done to get the event( edit SteppingVerbose.h, add a global variable to the class definition)

output : event number, Photon position, Electron position, Photon and Electron initial and final momentum.

3.) Compare output with BDSIM at 500 keV

4.) Insert new physics process for Low Energy Compton (done)

Still need to do 2 &3.

Compare hand calculation of an event or two with GEANT4 output

3/6/08

Goals for last week

1.) Compare hand calculation of an event or two with GEANT4 output

2.) add an event counter so we know how many beam triggers are done to get the event( edit SteppingVerbose.h, add a global variable to the class definition)

output : event number, Photon position, Electron position, Photon and Electron initial and final momentum.


3.) Compare output with BDSIM at 500 keV (BDSIM crashes at this high energy)

Tasks for next week:

1.) How many GEANT4 triggers does it take to get an event when E-gamma = 30 eV

Zero/10^7. However, if I set the E-gamma=300 eV then I see 1819 triggers out of 10 million iterations.

ComptonEvents At 300eV 3-12-08.jpg


2.) remove detector which blocks reactions for 0<Z<200 

   [box]Commented out Sensitive Detector function in DetectorConstruction.cc. I still see the SD in display[/box]

3.) Store tracking info for photon and electron into variables for printing out 

   [box]Show the text file for 300 eV laser and 20 MeV electron[/box]

4.) Compare BDSIM and GEANT4 for E-gamma = 300 or 30 eV 

   [box]BDSIM crashes at 300 eV[/box]

5.) Any measured X-sections for 2 eV Compton? 

   [box]Was not able to find on internet. BDSIM however, uses GEANT4 database...We might need to dig into their code, I got the source code[/box]

3/13/08

Tasks:

1.) fix output file so electons and photon from same event on same line 

  o Geant4 output.txt:
Variable value
# Triggers 153610
Compton Event # 1
Scattered Photon energy (keV) 0.299784
photon X position 0
photon Y position 0
photon Z position -441.431
photon X Momentum 6.30938e-05
photon Y Momentum 0.000285127
photon Z Momentum -6.77687e-05
Particle ID 22
Scattered e- KE (keV) 0.000215785
Scattered electron X position -177.027
Scattered electron Y position -800
Scattered electron Z position 590.444
Scattered electron X Momentum -6.30938e-05
Scattered electron Y Momentum -0.000285127
Scattered electron Z Momentum 0.000367769
Particle ID 11
[math]\lambda^{\prime} = \lambda + \lambda_C (1-\cos(\theta)) = \frac{2 \pi}{\omega^{\prime}} = \frac{ch}{E_{\gamma}^{\prime}} = \frac{12,400 \mbox{Angstroms}}{E_{\gamma}^{\prime}}[/math]
[math]\lambda_C[/math] = electron compton wavelength = [math]\frac{h}{m_ec} = 2.43 \times 10^{-12} m[/math]
[math]E_k = \hbar \omega \frac{\lambda_C}{\lambda} \frac{1- \cos(\theta)}{1 + \frac{\lambda_C}{\lambda} \left (1 - \cos(\theta) \right )}[/math] = electron final kinetic energy
[math]\phi = \cot \left [ \left ( 1+ \frac{\lambda_C}{\lambda}\right ) tan(\frac{\theta}{2}\right ][/math] = ejected electron angle w.r.t original photon direction
     15361 ||   1   || 0.299784   0   0   -441.431   6.30938e-05   0.000285127   -6.77687e-05   22   0.000215785   -177.027   -800   590.444   -6.30938e-05 -0.000285127   0.000367769   11   
    32685.8   2   0.299791   0   0   -131.765   -7.34024e-05   0.000285186   -5.61732e-05   22   0.000208981   192.024   -746.061   800   7.34024e-05   -0.000285186   0.000356173   11   
    33535.9   3   0.299682   0   0   -754.315   -0.000175966   -1.63899e-05   -0.000242026   22   0.000318029   504.599   46.9997   800   0.000175966   1.63899e-05   0.000542026   11   
      34157   4   0.299864   0   0   -579.415   -7.39129e-05   -0.000282637   6.7614e-05   22   0.00013635   209.21   800   78.3512   7.39129e-05   0.000282637   0.000232386   11

. . . .

2.)Compare compton scattering between BDSIM and GEANT4 for 300 eV photon incident on a 20 MeV electron

BDSIM GEANT4
Compton BDSIM Events At 300eV 3-19-08.jpg Compton Geant4 Events At 300eV 3-19-08.jpg 
o BDSIM (5,000,000 Iterations):



  Anglex BDSIM Events At 300eV 3-19-08.jpg
  Angley BDSIM Events At 300eV 3-19-08.jpg
  Momx BDSIM Events At 300eV 3-19-08.jpg
  Momy BDSIM Events At 300eV 3-19-08.jpg   
  Posz BDSIM Events At 300eV 3-19-08.jpg 

o Geant4 (5,000,000 iterations):



  Compton posx Geant4 Events At 300eV 3-19-08.jpg
  Compton posy Geant4 Events At 300eV 3-19-08.jpg
  Compton posz Geant4 Events At 300eV 3-19-08.jpg
 Electron Geant4 Events At 300eV 3-19-08.jpg
Compton momx Geant4 Events At 300eV 3-19-08.jpg
  Compton momy Geant4 Events At 300eV 3-19-08.jpg
  Compton momz Geant4 Events At 300eV 3-19-08.jpg
 
  Electron posx Geant4 Events At 300eV 3-19-08.jpg
  Electron posy Geant4 Events At 300eV 3-19-08.jpg
  Electron posz Geant4 Events At 300eV 3-19-08.jpg
  Electron momx Geant4 Events At 300eV 3-19-08.jpg
  Electron momy Geant4 Events At 300eV 3-19-08.jpg
  Electron momz Geant4 Events At 300eV 3-19-08.jpg


3.) remove physics processes and run 10^9 events piece mealed so you save event generator seed every 10^8 

o Still waiting for run_0.rndm, run_1.rndm...., files on inca. Process at the moment is executing!

3/20/08

Taks for next week

1.) Check elastic kinematics of LowEnergyCompton for case where electron is 1 eV and incident photon ranges between 300 ev and 8 keV 

output.txt for 1 eV electron and 8 keV gamma. Number of iterations: 1,000,000
Variable LowEnCompton_value Compton_value
# Triggers 53 48
Compton Event # 2 2
Scattered Photon energy (keV) 7.79307 7.76672
photon X position 0 0
photon Y position 0 0
photon Z position -752.482 -751.601
photon X Momentum -0.0050576 0.00228733
photon Y Momentum 0.00239243 -0.00204773
photon Z Momentum -0.00542483 -0.0071342
Particle ID 22 22
Scattered e- KE (keV) 0.206934 0.233283
Scattered electron X position 584.874 -234.503
Scattered electron Y position -276.667 209.94
Scattered electron Z position 800 800
Scattered electron X Momentum 0.0050576 -0.00228733
Scattered electron Y Momentum -0.00239243 0.00204773
Scattered electron Z Momentum 0.0134248 0.0151342
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 8 keV incoming Photons GEANT4_Compton, 8 keV incoming Photons
LowEnCompton At 1eVelectron 8keVphoton 4-06-08a.jpg Compton At 1eVelectron 8keVphoton 4-06-08a.jpg
GEANT4_LowEnCompton, 1 eV incoming Electrons GEANT4_Compton, 1 eV incoming Electrons
LowEnCompton At 1eVelectron 8keVphoton 4-06-08b.jpg Compton At 1eVelectron 8keVphoton 4-06-08b.jpg 
  output.txt for 1 eV electron and 300 eV gamma. Number of iterations: 2,000,000
Variable LowEnCompton_value Compton_value
# Triggers 32685 7123
Compton Event # 2 2
Scattered Photon energy (keV) 0.299791 0.299745
photon X position 0 0
photon Y position 0 0
photon Z position -131.765 554.105
photon X Momentum -7.34024e-05 0.000261431
photon Y Momentum 0.000285186 5.7275e-05
photon Z Momentum -5.61732e-05 -0.000134982
Particle ID 22 22
Scattered e- KE (keV) 0.000208981 0.000255222
Scattered electron X position 192.024 -147.787
Scattered electron Y position -746.061 -32.3775
Scattered electron Z position 800 800
Scattered electron X Momentum 7.34024e-05 -0.000261431
Scattered electron Y Momentum -0.000285186 -5.7275e-05
Scattered electron Z Momentum 0.000356173 0.000434982
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 300 eV incoming Photons GEANT4_Compton, 300 eV incoming Photons
LowEnCompton At 1eVelectron 300eVphoton 4-09-08a.jpg Compton At 1eVelectron 300eVphoton 4-09-08a.jpg
GEANT4_LowEnCompton, 1 eV incoming Electrons GEANT4_Compton, 1 eV incoming Electrons
LowEnCompton At 1eVelectron 300eVphoton 4-09-08b.jpg Compton At 1eVelectron 300eVphoton 4-09-08b.jpg 


see if #triggers is same as above when [math]E_{\gamma}[/math] = 800 eV and [math]E_{e}[/math] = 1 eV

2.) Same as above except now change the incident electron energy up to 20 MeV, 50 ev, 1 keV, 10 keV, 1Mev, 10 MeV 

output.txt for 20 MeV electron and 300 eV gamma. Number of Iterations: 2,000,000
Variable LowEnCompton_value Compton_value
# Triggers 32685 7123
Compton Event # 2 2
Scattered Photon energy (keV) 0.299791 0.299745
photon X position 0 0
photon Y position 0 0
photon Z position -131.765 554.105
photon X Momentum -7.34024e-05 0.000261431
photon Y Momentum 0.000285186 5.7275e-05
photon Z Momentum -5.61732e-05 -0.000134982
Particle ID 22 22
Scattered e- KE (keV) 0.000208981 0.000255222
Scattered electron X position 192.024 -147.787
Scattered electron Y position -746.061 -32.3775
Scattered electron Z position 800 800
Scattered electron X Momentum 7.34024e-05 -0.000261431
Scattered electron Y Momentum -0.000285186 -5.7275e-05
Scattered electron Z Momentum 0.000356173 0.000434982
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 300 eV incoming Photons GEANT4_Compton, 300 eV incoming Photons
LowEnCompton At 20MeVelectron 300eVphoton 4-09-08a.jpg Compton At 20MeVelectron 300eVphoton 4-09-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
LowEnCompton At 20MeVelectron 300eVphoton 4-09-08b.jpg Compton At 20MeVelectron 300eVphoton 4-09-08b.jpg


4/10/08

1.) check if cross section is same fore 100 eV < [math]E_{gamma}[/math] <800 eV

ComptRate-vs-Egamma 20MeVe.jpg 

Case-a) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=100 eV, process="LowEnCompton", #events: 2,000,000
              Result=0 interactions



Case-b) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=100 eV, process="Compton", #events: 2,000,000
              Result=0 interaction

Case-c) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=105 eV, process="LowEnCompton", #events: 2,000,000
              Result=0 interaction



Case-d) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=105 eV, process="Compton", #events: 2,000,000
              Result= 12 interactions
Variable LowEnCompton_value (case-c) Compton_value (case-d)
# Triggers 490155
Compton Event # 2
Scattered Photon energy (keV) 0.104974
photon X position 0
photon Y position 0
photon Z position -521.846
photon X Momentum 2.94637e-05
photon Y Momentum -9.85919e-05
photon Z Momentum -2.07632e-05
Particle ID 22 22
Scattered e- KE (keV) 2.58365e-05
Scattered electron X position -239.076
Scattered electron Y position 800
Scattered electron Z position 498.63
Scattered electron X Momentum -2.94637e-05
Scattered electron Y Momentum 9.85919e-05
Scattered electron Z Momentum 0.000125763
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 105 eV incoming Photons GEANT4_Compton, 105 eV incoming Photons
400 px Compton At 20MeVelectron 105eVphoton 4-16-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
400 px Compton At 20MeVelectron 105eVphoton 4-16-08b.jpg 
Case-e) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=150 eV, process="LowEnCompton", #events: 2,000,000
              Result=0 interaction



Case-f) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=150 eV, process="Compton", #events: 2,000,000
              Result= 93 interactions
Variable LowEnCompton_value (case-e) Compton_value (case-f)
# Triggers 36600
Compton Event # 2
Scattered Photon energy (keV) 0.149994
photon X position 0
photon Y position 0
photon Z position 331.001
photon X Momentum -6.9277e-05
photon Y Momentum -2.37144e-05
photon Z Momentum 0.000130907
Particle ID 22 22
Scattered e- KE (keV) 5.60297e-06
Scattered electron X position 800
Scattered electron Y position 273.85
Scattered electron Z position 551.485
Scattered electron X Momentum 6.9277e-05
Scattered electron Y Momentum 2.37144e-05
Scattered electron Z Momentum 1.9093e-05
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 150 eV incoming Photons GEANT4_Compton, 150 eV incoming Photons
400 px Compton At 20MeVelectron 150eVphoton 4-16-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
400 px Compton At 20MeVelectron 150eVphoton 4-16-08b.jpg 


Case-g) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=200 eV, process="LowEnCompton", #events: 2,000,000
              Result=0 interaction



Case-h) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=200 eV, process="Compton", #events: 2,000,000
              Result=  179 interactions
Variable LowEnCompton_value (case-g) Compton_value (case-h)
# Triggers 33713
Compton Event # 2
Scattered Photon energy (keV) 0.19991
photon X position 0
photon Y position 0
photon Z position 778.343
photon X Momentum 7.46479e-05
photon Y Momentum 0.000183052
photon Z Momentum -2.97293e-05
Particle ID 22 22
Scattered e- KE (keV) 8.98786e-05
Scattered electron X position -7.03722
Scattered electron Y position -17.2567
Scattered electron Z position 800
Scattered electron X Momentum -7.46479e-05
Scattered electron Y Momentum -0.000183052
Scattered electron Z Momentum 0.000229729
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 200 eV incoming Photons GEANT4_Compton, 200 eV incoming Photons
400 px Compton At 20MeVelectron 200eVphoton 4-16-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
400 px Compton At 20MeVelectron 200eVphoton 4-16-08b.jpg 


Case-i) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=400 eV, process="LowEnCompton", #events: 2,000,000
              Result= 697 interaction



Case-j) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=400 eV, process="Compton", #events: 2,000,000
              Result= 898 interactions
Variable LowEnCompton_value (case-i) Compton_value (case-j)
# Triggers 6012 5318
Compton Event # 2 2
Scattered Photon energy (keV) 0.399439 0.399849
photon X position 0 0
photon Y position 0 0
photon Z position 233.061 760.793
photon X Momentum -0.000130127 1.38275e-06
photon Y Momentum 0.000205697 0.000341899
photon Z Momentum -0.000316714 0.000207322
Particle ID 22 22
Scattered e- KE (keV) 0.000560591 0.000150707
Scattered electron X position 102.933 -0.281371
Scattered electron Y position -162.712 -69.5718
Scattered electron Z position 800 800
Scattered electron X Momentum 0.000130127 -1.38275e-06
Scattered electron Y Momentum -0.000205697 -0.000341899
Scattered electron Z Momentum 0.000716714 0.000192678
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 400 eV incoming Photons GEANT4_Compton, 400 eV incoming Photons
LowEnCompton At 20MeVelectron 400eVphoton 4-16-08a.jpg Compton At 20MeVelectron 400eVphoton 4-16-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
LowEnCompton At 20MeVelectron 400eVphoton 4-16-08b.jpg Compton At 20MeVelectron 400eVphoton 4-16-08b.jpg 


Case-k) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=800 eV, process="LowEnCompton", #events: 2,000,000
              Result= 2534 interactions



Case-l) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=800 eV, process="Compton", #events: 2,000,000
              Result= 3314 interactions
Variable LowEnCompton_value (case-k) Compton_value (case-l)
# Triggers 2033 1703
Compton Event # 2 2
Scattered Photon energy (keV) 0.798489 0.799399
photon X position 0 0
photon Y position 0 0
photon Z position 302.879 759.113
photon X Momentum 0.000776101 -0.000120116
photon Y Momentum -8.6914e-05 -0.000672133
photon Z Momentum -0.00016643 0.000415751
Particle ID 22 22
Scattered e- KE (keV) 0.00151064 0.000600626
Scattered electron X position -399.218 12.7812
Scattered electron Y position 44.7076 71.5199
Scattered electron Z position 800 800
Scattered electron X Momentum -0.000776101 0.000120116
Scattered electron Y Momentum 8.6914e-05 0.000672133
Scattered electron Z Momentum 0.00096643 0.000384249
Particle ID 11 11

o Plots

GEANT4_LowEnCompton, 800 eV incoming Photons GEANT4_Compton, 800 eV incoming Photons
LowEnCompton At 20MeVelectron 800eVphoton 4-16-08a.jpg Compton At 20MeVelectron 800eVphoton 4-16-08a.jpg
GEANT4_LowEnCompton, 20 MeV incoming Electrons GEANT4_Compton, 20 MeV incoming Electrons
LowEnCompton At 20MeVelectron 800eVphoton 4-16-08b.jpg Compton At 20MeVelectron 800eVphoton 4-16-08b.jpg


2.) Create your own Physics list subroutine called SyedCompton which is a renamed copy of LowEnergyCompton 

Created local SyedLowEnergyCompton and SyedCompton subroutines:

Case-m) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=800 eV, process="LowEnCompton", #events: 2,000,000
              Result= 2534 interactions



Case-n) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=800 eV, process="Compton", #events: 2,000,000
              Result= 3314 interactions
Variable SyedLowEnCompton_value (case-m) SyedCompton_value (case-n)
# Triggers 2033 1703
Compton Event # 2 2
Scattered Photon energy (keV) 0.798489 0.799399
photon X position 0 0
photon Y position 0 0
photon Z position 302.879 759.113
photon X Momentum 0.000776101 -0.000120116
photon Y Momentum -8.6914e-05 -0.000672133
photon Z Momentum -0.00016643 0.000415751
Particle ID 22 22
Scattered e- KE (keV) 0.00151064 0.000600626
Scattered electron X position -399.218 12.7812
Scattered electron Y position 44.7076 71.5199
Scattered electron Z position 800 800
Scattered electron X Momentum -0.000776101 0.000120116
Scattered electron Y Momentum 8.6914e-05 0.000672133
Scattered electron Z Momentum 0.00096643 0.000384249
Particle ID 11 11

o Plots

GEANT4_SyedLowEnCompton, 800 eV incoming Photons GEANT4_SyedCompton, 800 eV incoming Photons
SyedLowEnCompton At 20MeVelectron 800eVphoton 4-16-08a.jpg SyedCompton At 20MeVelectron 800eVphoton 4-16-08a.jpg
GEANT4_SyedLowEnCompton, 20 MeV incoming Electrons GEANT4_SyedCompton, 20 MeV incoming Electrons
SyedLowEnCompton At 20MeVelectron 800eVphoton 4-16-08b.jpg SyedCompton At 20MeVelectron 800eVphoton 4-16-08b.jpg



4/17/08

1.) Lower cutoff energy and redo rate plots from previous week. Created local SyedLowEnergyCompton and SyedCompton subroutines: 

Case-a) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=2.326 eV, process="LowEnCompton", #events: 2,000,000
              lowEnergyLimit(2*eV)
              intrinsicLowEnergyLimit(1*eV)
              Result=  270 interactions



Case-b) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=2.326 eV, process="Compton", #events: 2,000,000
              lowEnergyLimit(2*eV)
              Result= 0 interactions
Variable SyedLowEnCompton_value (case-a) SyedCompton_value (case-b)
# Triggers 18955
Compton Event # 2 2
Scattered Photon energy (keV) 0.002326
photon X position 0 0
photon Y position 0 0
photon Z position 601.57
photon X Momentum -6.4311e-10
photon Y Momentum -9.36186e-10
photon Z Momentum 2.326e-06
Particle ID 22 22
Scattered e- KE (keV) 1.26208e-15
Scattered electron X position 549.557
Scattered electron Y position 800
Scattered electron Z position 601.807
Scattered electron X Momentum 6.43062e-10
Scattered electron Y Momentum 9.36116e-10
Scattered electron Z Momentum 2.77288e-13
Particle ID 11 11

o Plots

GEANT4_SyedLowEnCompton, 2.326 eV incoming Photons GEANT4_SyedCompton, 2.326 eV incoming Photons
SyedLowEnCompton At 20MeVelectron 2.326eVphoton 4-23-08a.jpg 400 px
GEANT4_SyedLowEnCompton, 20 MeV incoming Electrons GEANT4_SyedCompton, 20 MeV incoming Electrons
SyedLowEnCompton At 20MeVelectron 2.326eVphoton 4-23-08b.jpg 400 px 


Case-c) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=2.326 eV, process="LowEnCompton", #events: 2,000,000
              lowEnergyLimit(2*eV)
              intrinsicLowEnergyLimit(0.1*eV)
              Result=  270 interactions



Case-d) [math]E_{electron}[/math]=20 MeV, [math]E_{\gamma}[/math]=2.326 eV, process="LowEnCompton", #events: 5,000,000
              lowEnergyLimit(2*eV)
              intrinsicLowEnergyLimit(0.1*eV)
              Result=  636 interactions
Variable SyedLowEnCompton_value (case-c) SyedLowEnCompton_value (case-d)
# Triggers 18955 18955
Compton Event # 2 2
Scattered Photon energy (keV) 0.002326 0.002326
photon X position 0 0
photon Y position 0 0
photon Z position 601.57 601.57
photon X Momentum -6.4311e-10 -6.4311e-10
photon Y Momentum -9.36186e-10 -9.36186e-10
photon Z Momentum 2.326e-06 2.326e-06
Particle ID 22 22
Scattered e- KE (keV) 1.26208e-15 1.26208e-15
Scattered electron X position 549.557 549.557
Scattered electron Y position 800 800
Scattered electron Z position 601.807 601.807
Scattered electron X Momentum 6.43062e-10 6.43062e-10
Scattered electron Y Momentum 9.36116e-10 9.36116e-10
Scattered electron Z Momentum 2.77288e-13 2.77288e-13
Particle ID 11 11

o Plots

GEANT4_SyedLowEnCompton, 2.326 eV incoming Photons(2-million events) GEANT4_SyedCompton, 2.326 eV incoming Photons (5-million events)
SyedLowEnCompton At 20MeVelectron 2.326eVphoton 4-23-08a.jpg SyedCompton At 20MeVelectron 2.326eVphoton 4-23-08c.jpg
GEANT4_SyedLowEnCompton, 20 MeV incoming Electrons(2-million events) GEANT4_SyedCompton, 20 MeV incoming Electrons(5-million events)
SyedLowEnCompton At 20MeVelectron 2.326eVphoton 4-23-08b.jpg SyedCompton At 20MeVelectron 2.326eVphoton 4-23-08cc.jpg


2.) After SyedCompton runs, change it so the final electron kinetic energy is calculated correctly. 

    Final Electron KE is approx. equals to 20MeV in this case because energy lost by incoming electrons is so small following
    Compton interaction as shown in above plots ...suggestions???

4/24/08

1.) Try HeP Lorentz vector class and set vectors within the SyedCompton routine

CLHEP Man 


HepLorentzVector P4eLab

P4eLab.setPx(HepDouble);


5/1/08

Got the class 

G4LorentzVector* P4eLab;

defined in SyedLowEnergyCompton.hh


Then created the variable 

 P4eLab = new G4LorentzVector;

 P4eLab->setPx(1.4596);

 G4cout << "P4e Px= " << P4eLab << G4endl;

in SyedLowEnergyCompton.cc


1.) Check the functionality of the function calls below to see if we understand how they work 

P4eLab->setPx(1.4596);
cout << "P4e " << P4eLab << endl;

cout << "rest 4 Vector" << P4eLab.rest4Vector() << endl;---->"These functions are not declared!"
cout << "rest 4 Vector" << P4eLab.rest4Vector().beta << endl;---->"These functions are not declared!"

2.) Look up relativistic Lorentz transformation to boost to electron rest frame. A fair start is at

http://www.iac.isu.edu/mediawiki/index.php/Forest_Relativity_Notes#Lorentz_Transformations

3.) check out reference

A.A. Sokolov and I.M. Ternov Sov. Phys. Dokl. 8 (1964), p. 1203.

may lead to a reference for our problem.

4.) Install GEANT4 on Brems 

   *done* but with graphics option was disabled, there are issues with OpenGL on brems and I was not able to compile MesaGL in my local folder

5.) create 2 sets of 24 random number seed files. The first set of 24 random number seed files will run for 2 hours and the second set will run for 24 hours. 

   *Compilation Error message on Brems:*
    Compiling LCS.cc ...
    Using global libraries ...
    Linking LCS ...
    /home/naeesyed/apps/geant4/geant4.9.1.p02/lib/Linux-g++/libG3toG4.so: undefined reference to `G3Division::UpdateVTE()'
    /home/naeesyed/apps/geant4/geant4.9.1.p02/lib/Linux-g++/libG3toG4.so: undefined reference to `G3Division::CreatePVReplica()'
    /home/naeesyed/apps/geant4/geant4.9.1.p02/lib/Linux-g++/libG3toG4.so: undefined reference to `G3Division::G3Division(G3DivType, G3VolTableEntry*,     G3VolTableEntry*, int, int, int, double, double)'
    /home/naeesyed/apps/geant4/geant4.9.1.p02/lib/Linux-g++/libG3toG4.so: undefined reference to `G3Division::G3Division(G3VolTableEntry*, G3VolTableEntry*, G3Division const&)'
    collect2: ld returned 1 exit status
    make: *** [/home/naeesyed/geant4/bin/Linux-g++/LCS] Error 1

6/12/08

1.) using interactive version of LCS test the transformations below

We have proton and electron. In the Lab frame electron is moving along the x-axis with momentum ;[math]\vec{p_e}[/math] and proton is at rest. The 4-vectors are:

Lab Frame
[math]P_e=[/math]([math]E_e[/math],[math]p_e[/math],0,0) and for proton :[math]P_p=[/math]([math]m_p[/math],0,0,0)
CM Frame
:[math]{P_e}^{\prime}=[/math]([math]{E_e}^{\prime}[/math],[math]{p_e}^{\prime}[/math],[math]0[/math],[math]0[/math]) and for proton :[math]{P_p}^{\prime}=[/math]([math]{E_p}^{\prime}[/math],[math]{p_p}^{\prime}[/math],[math]0[/math],[math]0[/math])
Find [math] \beta_{CM} [/math] such that [math]P_{tot}^{CM}=0 =p_e^{\prime} + {p_p}^{\prime}[/math]
[math]\left ( \begin{matrix} {E_e}^{\prime} \\ p_e^{\prime} \\ 0 \\ 0 \end{matrix} \right )= \left [ \begin{matrix} \gamma & -\gamma \beta & 0 & 0 \\ -\gamma \beta & \gamma &0 &0 \\ 0 &0 &1 &0 \\ 0 &0 &0 & 1 \end{matrix} \right ] \left ( \begin{matrix} E_e \\ p_e \\ 0 \\ 0 \end{matrix} \right )[/math]


[math]\left ( \begin{matrix} {E_p}^{\prime} \\ p_p^{\prime} \\ 0 \\ 0 \end{matrix} \right )= \left [ \begin{matrix} \gamma & -\gamma \beta & 0 & 0 \\ -\gamma \beta & \gamma &0 &0 \\ 0 &0 &1 &0 \\ 0 &0 &0 &1\end{matrix} \right ] \left ( \begin{matrix} m_p \\ 0 \\ 0 \\ 0 \end{matrix} \right )[/math]

Using the last two equations we will get the following for x component:

[math]{p_e}^{\prime}=-\gamma_{cm}(\beta_{cm} E_e-p_e)[/math]
[math]p_p^{\prime} = - \gamma_{cm} \beta_{cm} m_p[/math]
[math] \gamma_{cm}(p_e - \beta_{cm} E_e)= \gamma_{cm} \beta_{cm} m_p [/math]
[math]\beta_{cm} = \frac {p_e}{m_p + E_e}[/math]
Example
[math]p_e = 5.736 Gev \sim E_e[/math] : electron mass is neglibible
[math]m_p = 0.938 GeV[/math] : Mass of a proton
[math]\beta_{cm} = \frac{5.736}{6.674} = 0.859 \lt 1[/math]
[math]\gamma_{cm} = \frac{1}{\sqrt{1 - \beta_{cm}^2}} = \frac{1}{\sqrt{1 - 0.859^2}} = 1.9532[/math]
[math]\left ( \begin{matrix} {E_e}^{\prime} \\ p_{ex}^{\prime} \\ p_{ey}^{\prime} \\ p_{ez}^{\prime} \end{matrix} \right )= \left [ \begin{matrix} \gamma_{cm} & 0 & 0 & -\gamma_{cm} \beta_{cm} \\ 0 & 1 &0 &0 \\ 0 &0 &1 &0 \\ -\gamma_{cm} \beta_{cm} &0 &0 &\gamma_{cm}\end{matrix} \right ] \left ( \begin{matrix} E_e=4.4915 \\ -0.549 \\ 0.974 \\ 4.3501 \end{matrix} \right )[/math]
Electron
[math]\left ( \begin{matrix} {E_e}^{\prime} \\ p_{ex}^{\prime} \\ p_{ey}^{\prime} \\ p_{ez}^{\prime} \end{matrix} \right )= \left ( \begin{matrix} 4.4915 \gamma_{cm} - 4.3501 \gamma_{cm} \beta_{cm} \\ -0.549 \\ 0.974 \\ -4.4915 \gamma_{cm} \beta_{cm} + 4.3501 \gamma_{cm} \end{matrix} \right ) = \left ( \begin{matrix} 1.4742 \\ -0.549 \\ 0.974 \\ 0.96078 \end{matrix} \right )[/math]
In our case 4-vectors for particles are

[math](P_e)_\mu = ( 5.736, 0, 0, 5.736 GeV)[/math]
[math](P_p)_\mu = (m_p, 0, 0, 0)[/math]
[math]({P_e}^{\prime})_\mu = (4.4914861, -0.549, 0.974, 4.3501 )[/math]
[math]({P_{\pi^-}}^{\prime})_\mu = (0.575721, 0.1052, -0.4394, 0.3282)[/math]

Compiling on brems

1.) turned off a GUI and G3toG4 stuff

2.) edited $G4INSTALL/config/binmake.gmk and commmented out the VIS variables and include commands

3.) comment out interactive commands in LCS.cc so only batch mode would run


we are compiled now.

Practice submitting batch jobs via ssh command and the random number seed files.

Submitting batch jobs on brems

Concept: While logged into brems you can submit a job to run on bres 3 by using the ssh command via 

ssh brems3 source run0.script


the script "run0.script"

contains all the command you would type interactively in order to execute the program 

source ~/apps/geant4/geant4.9.1.p02/env.sh
cd /home/naeesyed/geant4/LCS/Laser_Compton_Backscattering/run0
LCS vis.mac > /dev/null

Khalid has cross sections in his interview talk

[math]\frac{d \sigma}{d \Omega} = \frac{1-\beta^2 }{1-\beta cos \theta} cos^2 \theta cos -\beta[/math]

9/5/08

Insert Transformation matrix to take electron beam in Lab frame to the electron in the electron's rest frame.

Find [math]\beta_R[/math]

Lab Frame
[math]P_e{\mu}=[/math]([math]E_e[/math],[math]p_e[/math],0,0) and for proton :[math]P_{\gamma}^{\mu}=[/math]([math]E_{\gamma}[/math],[math]P_{\gamma}[/math],0,0)
Transform from the LAB frome to a reference frame in which the electron is at rest
Find [math] \beta_{CM} [/math] such that [math]P_{tot}^{CM}=0 =p_e^{\prime} + {p_p}^{\prime}[/math]


[math] \beta_R = \frac{v_e}{c} = \frac {P_e}{E_e + m_e} =\frac {20MeV}{20MeV + 0.511MeV} = 0.975 \lt 1[/math]

[math] \gamma_R = \frac {1}\sqrt{1 - \beta_r^2} =\frac {1}\sqrt{1 - 0.975^2} = 4.5[/math]


The relativistic transformation matrix for the four momentum is given by


[math]\left ( \begin{matrix} {E_e}^{\prime} \\ p_e^{\prime} \\ 0 \\ 0 \end{matrix} \right )= \left [ \begin{matrix} \gamma & -\gamma \beta & 0 & 0 \\ -\gamma \beta & \gamma &0 &0 \\ 0 &0 &1 &0 \\ 0 &0 &0 & 1 \end{matrix} \right ] \left ( \begin{matrix} E_e \\ p_e \\ 0 \\ 0 \end{matrix} \right )[/math]
[math]\left ( \begin{matrix} {E_g}^{\prime} \\ p_g^{\prime} \\ 0 \\ 0 \end{matrix} \right )= \left [ \begin{matrix} \gamma & -\gamma \beta & 0 & 0 \\ -\gamma \beta & \gamma &0 &0 \\ 0 &0 &1 &0 \\ 0 &0 &0 & 1 \end{matrix} \right ] \left ( \begin{matrix} E_g \\ p_g \\ 0 \\ 0 \end{matrix} \right )[/math]
[math]\left ( \begin{matrix} {E_e}^{\prime} \\ p_e^{\prime} \\ 0 \\ 0 \end{matrix} \right )= \left [ \begin{matrix} \gamma & -\gamma \beta & 0 & 0 \\ -\gamma \beta & \gamma &0 &0 \\ 0 &0 &1 &0 \\ 0 &0 &0 & 1 \end{matrix} \right ] \left ( \begin{matrix} E_{\gamma} \\ p_{\gamma} \\ 0 \\ 0 \end{matrix} \right )[/math]



Insert Transformation matrix to transform outgoing X-ray momentum four vector in the Lab from to the electron at rest frame.


[math]P_e^{\mu} =\left(E_e^R, P_{ex}^R, P_{ey}^R, P_{ez}^R\right) = (2.25MeV, 0, 0, 2.25)[/math] 

 Was the energy of 2.25 MeV just chosen as an example?
 This is the calculated electron energy in C.M. frame.

Write equation for [math]\theta_R[/math]= angle of the outgoing X-ray in the electron rest frame.

[math] \theta_{f,R} = cos^{-1} (\frac {-\gamma_R \beta_R E_e^{lab frame} + \gamma_R P_{e_z}^{lab frame}}{P_{e_z}}) = cos^{-1} (\frac {(-4.5*0.975*20 ) + (4.5*20)}{2.25}) = 0^o[/math]

Klein-Nishina Compton Cross Section

Khalid LCS paper:File:Chouffani PhysRevST 050701 2006 pg9.pdf


Questions: Why [math]\theta[/math] and [math]\theta_d[/math] ? 

[math]\theta_d[/math] is the detector's angle with respect to incoming LCS X-rays.


9/26/08

1.) Use B= 0.975 to transform photon to electrons rest frame inside the event generator

for a few events check

[math]E_\gamma[/math] before and after 


// muon momenta in the primary's rest frame
 CLHEP::HepLorentzVector pMu1 ( p0x, p0y, p0z, p00 );
 CLHEP::HepLorentzVector pMu2 ( -p0x, -p0y, -p0z, p00 );

 // muon momenta in the boosted frame
 CLHEP::HepLorentzVector boostedPMu1 = pMu1.boostZ ( beta );
 CLHEP::HepLorentzVector boostedPMu2 = pMu2.boostZ ( beta );



 Declared the following in the event generator:
 
 //declaring G4LorentzVector for both electrons and gammas
 G4double beta = 0.975;
 p4eLab = new G4LorentzVector;
 p4gammaLab = new G4LorentzVector;

 p4gammaBoostedx = new G4LorentzVector;  
 p4gammaBoostedy = new G4LorentzVector;
 p4gammaBoostedz = new G4LorentzVector;

 p4eBoostedx = new G4LorentzVector;
 p4eBoostedy = new G4LorentzVector;
 p4eBoostedz = new G4LorentzVector;



 However, I'm stuck with in getting momentum values in the lab frame for both electrons and gammas...G4ParticleDefinition doesn't
 include "getMomentum"   function and we need momentums in the lab frame that could be passed in the above declared variables?--
 Daq 09:28, 3 October 2008 (MDT)

 Update: "ExN02EventAction" class is getting momentum values of the existing event, I declared above variables in EventAction class.
 // get information on primary particle

     G4PrimaryParticle* primary=evt->GetPrimaryVertex(0)->GetPrimary(0);

     //Added by Syed
     p4eLab(primary->GetMomentum().x(),primary->GetMomentum().y(),primary->GetMomentum().z(), primary->GetEnergy());

     p4eBoostedx = p4eLab.boostX(beta);
     p4eBoostedy = p4eLab.boostY(beta);
     p4eBoostedz = p4eLab.boostZ(beta);
     Now, the question is where to LorentzBoost gammas?
 --Daq 13:26, 3 October 2008 (MDT)

reference

2.) Now take tracking verbose output and by a hand calculation transform the outgoing photon [math]P^{\mu}[/math] to the lab frame


3.) Check EventAction to see if the photon momentum and energy are being passed


10/3/08

1.) In event generator:

Boost electron and gamma and compare with hand calculation. (Units: MeV) 

P4e LabFrame w/o boost= (20 ,0 ,0 ,20)
P4e RestFrame w boost= (177.764 ,0 ,0 ,177.764)
P4gamma LabFrame w/o boost = (2.236e-06 ,0 ,0 ,2.236e-06)
P4gamma RestFrame w boost= (1.9874e-05 ,0 ,0 ,1.9874e-05)

Using findBoostToCM() function of Hep3Vector
p4e RestFrame w/ findBoostToCM function= ((-0,-0,-1))
p4gamma RestFrame w/ findBoostToCM function= ((-0,-0,-1))


10/10/08

[math]\beta[/math]=0.975, [math]Ee[/math]=20 MeV 

P4e RestFrame w/o boost= (20.0065 ,0 ,0 ,20)
Electron Rest w/o boost mass = 0.511
P4e RestFrame w/ boost= (2.27955 ,0 ,0 ,2.22154)
Electron Rest w/ boost mass = 0.511


[math]\beta[/math]=0.9996737585, [math]Ee[/math]=20 MeV, [math]E\gamma[/math]=2.236 eV 

P4e RestFrame w/o boost= (20.0065 ,0 ,0 ,20)
Electron Rest w/o boost mass = 0.511
P4e RestFrame w/ boost= (0.511 ,0 ,0 ,-2.48526e-08)
Electron Rest w/ boost mass = 0.511

P4gamma RestFrame w/o boost = (2.236e-06 ,0 ,0 ,2.236e-06)
P4gamma RestFrame w/ boost= (2.85602e-08 ,0 ,0 ,2.85602e-08)

Simulation

i) No. of events=10,000,000 

P4e RestFrame w/ boost= (0.511 ,0 ,0 ,-2.48526e-08)
P4gamma RestFrame w/ boost= (2.85602e-08 ,0 ,0 ,2.85602e-08)
LowEnCompton events=0
-------------------------------------------------------------
lowEnergyLimit(0*eV): Cannot be set below 1 eV, getting G4Exception error message if I set the intrinsic low energy below 1 eV and 1eV > 2.85602e-08 MeV

ii) No. of events executing on inca=100,000,000 

 P4e RestFrame w/ boost= (0.511 ,0 ,0 ,-2.48526e-08)
 P4gamma RestFrame w/o boost = (2.236e-06 ,0 ,0 ,2.236e-06)

/home/syed/geant4/LCS/Laser_Compton_Backscattering/output.txt format: 

 ComptonEventTrigger/10, ComptonEventCounter, fTrack->GetKineticEnergy())*1000, fTrack->GetPosition().x(), fTrack->GetPosition().y(),
fTrack->GetPosition().z(), fTrack->GetMomentum().x(), fTrack->GetMomentum().y(), fTrack->GetMomentum().z(),
fTrack->GetDefinition()->GetPDGEncoding(), electronKE, electronxPosition, electronyPosition, electronzPosition, electronxMomentum, 
electronyMomentum, electronzMomentum, electronPDGID


10/17/08

The boosted electron and gamma energies seem to be working now 

P4e RestFrame w/o boost= (20.0065 ,0 ,0 ,20)
P4e RestFrame w/ boost= (0.511 ,0 ,0 ,-2.48526e-08)
P4gamma RestFrame w/o boost = (2.236e-06 ,0 ,0 ,-2.236e-06)
P4gamma RestFrame w/ boost= (0.000175058 ,0 ,0 ,-0.000175058)


What should gamma energy be after boosting to electron rest frame? 

[math]\beta[/math]=0.9996737585
[math]P\gamma_z[/math]= 2.326 eV
Hand calculated value is [math]E\gamma[/math] = 0.03 eV from [math]E\gamma[/math] =2.236 eV.
Computer simulated value is [math]E\gamma[/math] = 0.0285602 eV from [math]E\gamma[/math] =2.236 eV. 
----------------------------------------------------------------------------------------------------
[math]\beta[/math]=0.9996737585
[math]P\gamma_z[/math]= -2.326 eV
Hand calculated value is [math]E\gamma[/math] = 181.05 eV from [math]E\gamma[/math] =2.236 eV.
Computer simulated value is [math]E\gamma[/math] = 175.058 eV from [math]E\gamma[/math] = 2.236 eV.


Now boost the electron and gamma vectors back to the lab frame in Stepping Verbose 

 Number of events executed: 20 million
GEANT4_SyedLowEnCompton, [math]E\gamma[/math]:266 nm=4.652 eV (for 532 nm laser), [math]E_e[/math]=20 MeV GEANT4_SyedLowEnCompton, [math]E\gamma[/math]:266 nm=4.652 eV (for 532 nm laser), [math]E_e[/math]=20 MeV
LowEnCompton At 20MeVelectron 2.326eVphoton 10-24-08a.jpg LowEnCompton At 20MeVelectron 2.326eVphoton 10-24-08b.jpg
GEANT4_SyedLowEnCompton, [math]E\gamma[/math]:532 nm=2.326 eV (for 1064 nm laser), [math]E_e[/math]=20 MeV GEANT4_SyedLowEnCompton, [math]E\gamma[/math]:532 nm=2.326 eV (for 1064 nm laser), [math]E_e[/math]=20 MeV
LowEnCompton At 20MeVelectron 2.326eVphoton 10-24-08c.jpg LowEnCompton At 20MeVelectron 2.326eVphoton 10-24-08d.jpg

Equation 1 from Reference File:Chouffani JCPDS 2003 46 pg73.pdf says that the backsattered x-ray energy is given by

[math]E_\gamma = \frac{4\gamma^2E_{laser}}{1 +\gamma^2 \theta^2}[/math]


[math] (E^{max}_\gamma) [/math]@532nm = [math] 4\gamma^2E_{laser}=4\left(\frac{E_e}{m_e}\right)^2E_{laser}= 4\left(\frac{20 MeV}{0.511 MeV}\right)^2 2.326 eV = 14.252 keV[/math]

[math] (E^{max}_\gamma) [/math]@1064nm = [math] 4\gamma^2E_{laser}= 4\left(\frac{20 MeV}{0.511 MeV}\right)^2 1.163 eV = 7.126 keV[/math]

10/24/08

Now compare BDSIM output to GEANT4 output with the boosting based Laser compton scattering physics process.

Number of events executed: 1 million

BDSIM, [math]\lambda_laser[/math]:266nm (for 532nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
BDSIM At 20MeVelectron 2.326eVphoton 10-26-08a.jpg BDSIM At 20MeVelectron 2.326eVphoton 10-24-08b.jpg
BDSIM, [math]\lambda_laser[/math]:532nm (for 1064nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
BDSIM At 20MeVelectron 1eVphoton 10-26-08a.jpg BDSIM At 20MeVelectron 1eVphoton 10-24-08b.jpg 
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Geant4_lowEnCompton, [math]\lambda_laser[/math]:266nm (for 532nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
Geant4 At 20MeVelectron 2.326eVphoton 10-30-08a.jpg Geant4 At 20MeVelectron 2.326eVphoton 10-30-08b.jpg
Geant4_lowEnCompton, [math]\lambda_laser[/math]:532nm (for 1064nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
Geant4 At 20MeVelectron 1eVphoton 10-30-08a.jpg Geant4 At 20MeVelectron 1eVphoton 10-30-08b.jpg
Geant4_Compton, [math]\lambda_laser[/math]:266nm (for 532nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
Geant4 At 20MeVelectron 2.326eVphoton 10-30-08c.jpg Geant4 At 20MeVelectron 2.326eVphoton 10-30-08d.jpg
Geant4_Compton, [math]\lambda_laser[/math]:532nm (for 1064nm laser), [math]E_e[/math]=20 MeV Angular dependence (Head-on collision)
Geant4 At 20MeVelectron 1eVphoton 10-30-08c.jpg Geant4 At 20MeVelectron 1eVphoton 10-30-08d.jpg



A 522 nm wavelength photon is

[math]E_\gamma = h \nu = \frac{ c h}{\lambda} [/math]
[math]E_\gamma = \frac{6.2 \times 10^{-34} J sec \times 3 \times 10^8 m/sec}{532 \times 10 ^{-9} m} \frac{ eV } {1.6 \times 10^-{19} J} =[/math]
[math]E_\gamma = 2.18 eV[/math]
Why does GEANT4 and BDSIM give a max compton [math]E_{\gamma}[/math] of 7 keV when using an input photon energy of 2.18 eV instead of 14 keV as predicted by the above formula.  A factor of 2 difference exits!

Now that we have source code for a compton scattering process, lets compare its output to some observables.

1.) Check if the [math]\theta[/math] dependence is shown by the simulation 

   Done; see above plots
[math]E_\gamma = \frac{4\gamma^2E_{laser}}{1 +\gamma^2 \theta^2}[/math]


usefull root command: 

LCS->makeCode();

or 

LCS->MakeClass();


2.) Plot the scattered electron kinetic energy distribution and compare it with predictions from the Klein Nishina formula.

Geant4 [math]\lambda_laser[/math]:266nm (for 532 nm laser), [math]E_e[/math]=20 MeV Geant4 [math]\lambda_laser[/math]:532nm (for 1064nm laser), [math]E_e[/math]=20 MeV
Geant4 At 20MeVelectron 2.326eVphoton 10-30-08e.jpg Geant4 At 20MeVelectron 2.326eVphoton 10-30-08f.jpg

3.) Save random number for Comptom event. 

   Done

4.) Write Kelin Nishina cross section formula in your Compton scattering physics process.


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