July2012PosSimulation

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In G4beamline manual "The electromagnetic processes of these physics lists are advertised to be valid above a few hundred electron Volts; Geant4 has a set of low energy electromagnetic processes, indicated by a suffix “_EMX” in the physics list name."

2 MeV Positrons

Measured Electron energy distribution at 10 MeV on 1.mm target

Simulation steps

1.) GEANT4 Simulated Beam energy distribution


2.) GEANT4 Simulated Positrons emitted from 1.x mm thick target


3.) Now use above Positron distribution as the particle source for G4beamline

Positrons hitting Tungsten Converter target

4.) Use GEANT4 to determine 511s from the positrons distribution impinging converter target

Oct 16th 2012 BenchMark

stages:

1. Program to input emittance, output beamsize, beam, divergence and beam energy.

2. e- on W, outcome e+. Incident electron distribution on T1. with general particle source with step 1 histogram. check graph x, y, z theta, En_dis out_put is the input. (directory for each).

3. insert T1 and generate positron distribution.

4. Acceleractor code to transport positron along the beamline. Out put positron theta, beamsize (x,y), energy distribution, out puts transported positron.

5. Geant4 takes step 4 output generates gamma (and other e+,e-) and look at those goes to detectors. beamline, plus shielding, and detectors.

HRRL pos sim benchmark Oct 16th 2012 update.jpg

Simulations

Partical Data Ground ID: PDGid=11 is electron. PDGid=-11 is positron. PDGid=22 is photon.

Parameters

Dipole vacuum chamber width is [math] 17 \pm 0.5 [/math] mm

The cavity exit diameter is about 7.3 mm.


Energy Spread Two Skewed Gaussian Fit

Energy spread fitted with two skewed Gaussian.

Hrrl 17May2012 12MeV En Spread2.png

Beam Distributions Beyond RMS: Media:Beam_Distributions_Beyond_RMS.pdf 


Amplitude = 2.13894, mean = 12.07181, sigma_L = 4.46986, sigma_R = 1.20046 

Sigma = 2.83516, Skewness = -0.57658 

Amplitude2 = 10.88318, mean2 = 12.32332, sigma_L2 = 0.69709, sigma_R2 = 0.45170 

Sigma2 = 0.57440, Skewness2 = -0.21360

Electron Distribution Upstream and Positron Distribution Downstream of Target1

simulation: Electron Distribution Upstream and Positron Distribution Downstream of Target1

3067274 Electrons fired.

T1_s=943.5

FDT1_s=$T1_s-26.52

BDT1_s=$T1_s+26.52

Thickness of T1 is 1.016 mm, radius of T1 is 15.875 mm (0.625 inches).

HRRL pos Jul2012 sim FDT1 BDT1 T1.png

HRRL pos Jul2012 sim FDT1 BDT1 Oerlay.png


Step 1: Generating positron from electron beam

Detector is after T1 to saple positron distribution. 13,799,743,800 electrons shot at the tungsten target to generate positrons.

step 1: ratio

DDNT1 = Detector DowN from T1

DQ4 = Detector at entrance Quad 4 located right after T1

DD1 = Detector at entrance of the first Dipole.

e-(DUPT1) = 13,799,743,800

e+(DDNT1) = [math]1.095179 \times 10^7[/math]

e+(DQ4) = [math]62780[/math]

e+(DQ4) = [math]6742[/math]


e-(DUPT1)/e+(DDNT1) = 1260

e-(DUPT1)/e+(DQ4) = 219811 = [math]2.2 \times 10^5[/math]

e-(DUPT1)/e+(DD1) = 2046832 = [math]2.0 \times 10^6[/math]


e+(DDNT1)/e+(DQ4) = 174

e+(DDNT1)/e+(DD1) = 1624


e+(DQ4)/e+(DD1) = 9.3

Step 1: Generated Beam on DDNT1

Detector down T1:

Positrons on detector right before Q4.

X profile Hrrl pos sim s2 beam DDNT1 x s1.png

Y profile (why is the distribution clipped on the left side in the figure) Hrrl pos sim s2 beam DDNT1 y s1.png


X divergence profile Hrrl pos sim s2 beam DDNT1 xp s1.png

Y divergence profile Hrrl pos sim s2 beam DDNT1 yp s1.png

Momentum distribution Hrrl pos sim s2 beam DDNT1 mom s1.png

Momentum distribution Hrrl pos sim s2 beam DDNT1 En s1.png

Sharp drop issue

The Y-position distribution of the beam shown in Figure ~\ref{sim-DDNT1-y-vs-x} has a sharp drop in the region between -25.8 mm and -27.2 mm that corresponds to the boundary of the target T1. Figure ~\ref{sim-DDNT1-T1-geo} shows the geometry of the target T1 and the sensitive detector DDNT1. If the target size was increased, it would eventually intersected the detector DDNT1 at a distance of 25.8 mm from the beam center. A 1.4 mm wide stripe of low counts is visible on DDNT1 that is a result of the target's thickness of 1.016 mm and the 45 degree angle of intersection. ([math]1.016 \sqrt{2}=1.44[/math]). The edge of the target does not produce many positrons compared to the face of the target, and as a result you see the stripe.

As shown in figures ~\ref{sim-DDNT1-theta-vs-y} and ~\ref{sim-DDNT1-theta-vs-y-zoom} (zoomed figure) the positron distribution decrease occures at [math]\theta = 45^o[/math]. Positrons are emitted from both the downstream and upstream side of the target. As shown in the figure, positrons from the downstream side of the target intersect the detector at angles below 45 degrees while positrons from the upstream side of the target begin to hit the detector at angles beyond 45 degrees. The 1.4 mm gap represents the transition of positrons between these two extremes.

Hrrl pos sim pos sharp drop geometry2.png

Hrrl pos sim s2 beam DDNT1 xy zoom s1.png Hrrl pos sim s2 beam DDNT1 xy zoom2 s1.png

Cut off line is around 26.5 mm corresponding to the large angle.

Hrrl pos sim beam DDNT1 y yp s1.png Hrrl pos sim beam DDNT1 y yp zoom s1.png


Hrrl pos sim s2 beam DDNT1 y s1.png Hrrl pos sim s2 beam DDNT1 xy s1.png

Hrrl pos sim s2 beam DDNT1 yp s1.png Hrrl pos sim s2 beam DDNT1 xpyp s1.png


DDNT1 is at 26.52 mm (53.04 mm)downstream of T1.

T1 radius is 25.4 mm (d=50.8 mm)

DDNT1 radius is 31.75 mm (d=63.5 mm).


Hrrl pos sim s2 beam DDNT1 xy zoom s1.png


Hrrl pos sim pos sharp drop geometry.png

Step 1: Generated Beam on DQ4

Positrons on detector right before Q4.

X profile Hrrl pos sim s2 beam DQ4 x s1.png

Y profile Hrrl pos sim s2 beam DQ4 y s1.png

X divergence profile Hrrl pos sim s2 beam DQ4 xp s1.png

Y divergence profile Hrrl pos sim s2 beam DQ4 yp s1.png

Momentum distribution Hrrl pos sim s2 beam DQ4 mom s1.png

Momentum distribution Hrrl pos sim s2 beam DQ4 En s1.png

Step 1: Generated Beam on DD1

Positrons on detector right before D1 - first dipole.

X profile Hrrl pos sim s2 beam DD1 x s1.png

Y profile Hrrl pos sim s2 beam DD1 y s1.png

X divergence profile Hrrl pos sim s2 beam DD1 xp s1.png

Y divergence profile Hrrl pos sim s2 beam DD1 yp s1.png

Momentum distribution Hrrl pos sim s2 beam DD1 mom s1.png

Momentum distribution Hrrl pos sim s2 beam DD1 En s1.png

Step 2: generate positron

The positrons after T1 is detected on a virtual detector. The positrons beam size, divergence and momentum distributions are extracted and created new positron beam.

Generate positron beam from the detector after T1 and transport it to right before D1.

221032400*16=3,536,518,400 positrons generated.

step 2: ratio

e+(DDNT1)/e+(DQ4) = 3536518400/47788670 = 74

e+(DDNT1)/e+(DD1) = 3536518400/5464220 = 647

e+(DQ4)/e+(DD1) = 8.7

Generated Beam on DQ4

Positrons on detector right before Q4.

X profile Hrrl pos sim s2 beam DQ4 x.png

Y profile Hrrl pos sim s2 beam DQ4 y.png

X divergence profile Hrrl pos sim s2 beam DQ4 xp.png

Y divergence profile Hrrl pos sim s2 beam DQ4 yp.png

Momentum distribution Hrrl pos sim s2 beam DQ4 mom.png

Momentum distribution Hrrl pos sim s2 beam DQ4 En.png


Generated Beam on DD1

Positrons on detector right before D1 - first dipole.

X profile Hrrl pos sim s2 beam DD1 x.png

Y profile Hrrl pos sim s2 beam DD1 y.png

X divergence profile Hrrl pos sim s2 beam DD1 xp.png

Y divergence profile Hrrl pos sim s2 beam DD1 yp.png

Momentum distribution Hrrl pos sim s2 beam DD1 mom.png

Momentum distribution Hrrl pos sim s2 beam DD1 En.png

Beam Compare Step1 and Step2

Compare Ratio

S1 S2
e-(DDT1)/e+(DDNT1) 1248
e-(DDT1)/e+(DQ4) 123698
e-(DDT1)/e+(DD1) 936846
e+(DDNT1)/e+(DQ4) 99 74
e+(DDNT1)/e+(DD1) 750 647
e+(DQ4)/e+(DD1) 7.6 8.7

Positrons at DDNT1

Step 1 Step 2
X profile Hrrl pos sim s2 beam DDNT1 x s1.png
Y profile Hrrl pos sim s2 beam DDNT1 y s1.png
X divergence profile Hrrl pos sim s2 beam DDNT1 xp s1.png
Y divergence profile Hrrl pos sim s2 beam DDNT1 yp s1.png
Momentum distribution Hrrl pos sim s2 beam DDNT1 mom s1.png
Momentum distribution Hrrl pos sim s2 beam DDNT1 En s1.png


Compare at DQ4

Step 1 Step 2
X profile Hrrl pos sim s2 beam DQ4 x s1.png Hrrl pos sim s2 beam DQ4 x.png
Y profile Hrrl pos sim s2 beam DQ4 y s1.png Hrrl pos sim s2 beam DQ4 y.png
X divergence profile Hrrl pos sim s2 beam DQ4 xp s1.png Hrrl pos sim s2 beam DQ4 xp.png
Y divergence profile Hrrl pos sim s2 beam DQ4 yp s1.png Hrrl pos sim s2 beam DQ4 yp.png
Momentum distribution Hrrl pos sim s2 beam DQ4 mom s1.png Hrrl pos sim s2 beam DQ4 mom.png
Momentum distribution Hrrl pos sim s2 beam DQ4 En s1.png Hrrl pos sim s2 beam DQ4 En.png

Compare at DD1

Step 1 Step 2
X profile Hrrl pos sim s2 beam DD1 x s1.png Hrrl pos sim s2 beam DD1 x.png
Y profile Hrrl pos sim s2 beam DD1 y s1.png Hrrl pos sim s2 beam DD1 y.png
X divergence profile Hrrl pos sim s2 beam DD1 xp s1.png Hrrl pos sim s2 beam DD1 xp.png
Y divergence profile Hrrl pos sim s2 beam DD1 yp s1.png Hrrl pos sim s2 beam DD1 yp.png
Momentum distribution Hrrl pos sim s2 beam DD1 mom s1.png Hrrl pos sim s2 beam DD1 mom.png
Momentum distribution Hrrl pos sim s2 beam DD1 En s1.png Hrrl pos sim s2 beam DD1 En.png


S3

Counts DD1UP DD45 DD2ND DT2UP DT2UP (Px>0) DT2UP (Px>)
1 MeV [math]1.4\times10^8[/math] ST sim s3 1Mev En D1UP.png [math]3.8 \times 10^5[/math]ST sim s3 1Mev En D45.png [math]1.8 \times 10^3[/math] ST sim s3 1Mev En DD2ND.png [math]1.2 \times 10^1[/math] ST sim s3 1Mev En DT2ND.png 300 px 300 px
2 MeV [math]1.4\times10^8[/math] ST sim s3 2Mev En D1UP.png [math]2.6 \times 10^6[/math]ST sim s3 2Mev En D45.png [math]6.1 \times 10^4[/math]ST sim s3 2Mev En DD2ND.png [math]4.3 \times 10^2[/math] ST sim s3 2Mev En DT2ND.png [math]4.2 \times 10^2[/math]ST sim s3 2Mev En DT2ND BT 0.png [math]1.1 \times 10^2[/math]ST sim s3 2Mev En DT2ND BT A.png
3 MeV [math]1.4\times10^8[/math] ST sim s3 3Mev En D1UP.png [math]5.9 \times 10^6[/math]ST sim s3 3Mev En D45.png [math]4.2 \times 10^5[/math]ST sim s3 3Mev En DD2ND.png [math]2.3 \times 10^3[/math]ST sim s3 3Mev En DT2ND.png [math]2.1 \times 10^3[/math]ST sim s3 3Mev En DT2ND BT 0.png [math]1.5 \times 10^3[/math]ST sim s3 3Mev En DT2ND BT A.png
4 MeV [math]1.4\times10^8[/math] ST sim s3 4Mev En D1UP.png [math]5.1 \times 10^6[/math]ST sim s3 4Mev En D45.png [math]5.9 \times 10^5[/math]ST sim s3 4Mev En DD2ND.png [math]4.4 \times 10^3[/math] ST sim s3 4Mev En DT2ND.png [math]4.0 \times 10^3[/math]ST sim s3 4Mev En DT2ND BT 0.png [math]2.9 \times 10^3[/math]ST sim s3 4Mev En DT2ND BT A.png
5 MeV [math]1.4\times10^8[/math] ST sim s3 5Mev En D1UP.png [math]4.8 \times 10^6[/math]ST sim s3 5Mev En D45.png [math]7.4 \times 10^5[/math]ST sim s3 5Mev En DD2ND.png [math]5.0 \times 10^3[/math] ST sim s3 5Mev En DT2ND.png [math]4.6 \times 10^3[/math]ST sim s3 5Mev En DT2ND BT 0.png [math]3.2 \times 10^3[/math]ST sim s3 5Mev En DT2ND BT A.png


Counts DD1UP DD45 DD2ND DT2UP DT2UP (Px>0) DT2UP (Px>)
1 MeV [math]1.4\times10^8[/math] [math]3.8 \times 10^5[/math] [math]1.8 \times 10^3[/math] [math]1.2 \times 10^1[/math]
2 MeV [math]1.4\times10^8[/math] [math]2.6 \times 10^6[/math] [math]6.1 \times 10^4[/math] [math]4.3 \times 10^2[/math] [math]4.2 \times 10^2[/math] [math]1.1 \times 10^2[/math]
3 MeV [math]1.4\times10^8[/math] [math]5.9 \times 10^6[/math] [math]4.2 \times 10^5[/math] [math]2.3 \times 10^3[/math] [math]2.1 \times 10^3[/math] [math]1.5 \times 10^3[/math]
4 MeV [math]1.4\times10^8[/math] [math]5.1 \times 10^6[/math] [math]5.9 \times 10^5[/math] [math]4.4 \times 10^3[/math] [math]4.0 \times 10^3[/math] [math]2.9 \times 10^3[/math]
5 MeV [math]1.4\times10^8[/math] [math]4.8 \times 10^6[/math] [math]7.4 \times 10^5[/math] [math]5.0 \times 10^3[/math] [math]4.6 \times 10^3[/math] [math]3.2 \times 10^3[/math]

1 MeV

En @ DD1UP ST sim s3 1Mev En D1UP.png

En @ DD45 ST sim s3 1Mev En D45.png

En @ DD2ND ST sim s3 1Mev En DD2ND.png

En @ DT2ND ST sim s3 1Mev En DT2ND.png

En @ DT2ND 300 px

En @ DT2ND 300 px


2 MeV

En @ DD1UP ST sim s3 2Mev En D1UP.png

En @ DD45 ST sim s3 2Mev En D45.png

En @ DD2ND ST sim s3 2Mev En DD2ND.png

En @ DT2ND ST sim s3 2Mev En DT2ND.png

En @ DT2ND ST sim s3 2Mev En DT2ND BT 0.png

En @ DT2ND ST sim s3 2Mev En DT2ND BT A.png

3 MeV

En @ DD1UP ST sim s3 3Mev En D1UP.png

En @ DD45 ST sim s3 3Mev En D45.png

En @ DD2ND ST sim s3 3Mev En DD2ND.png

En @ DT2ND ST sim s3 3Mev En DT2ND.png

En @ DT2ND ST sim s3 3Mev En DT2ND BT 0.png

En @ DT2ND ST sim s3 3Mev En DT2ND BT A.png

4 MeV

En @ DD1UP ST sim s3 4Mev En D1UP.png

En @ DD45 ST sim s3 4Mev En D45.png

En @ DD2ND ST sim s3 4Mev En DD2ND.png

En @ DT2ND ST sim s3 4Mev En DT2ND.png

En @ DT2ND ST sim s3 4Mev En DT2ND BT 0.png

En @ DT2ND ST sim s3 4Mev En DT2ND BT A.png

5 MeV

En @ DD1UP ST sim s3 5Mev En D1UP.png

En @ DD45 ST sim s3 5Mev En D45.png

En @ DD2ND ST sim s3 5Mev En DD2ND.png

En @ DT2ND ST sim s3 5Mev En DT2ND.png

En @ DT2ND ST sim s3 5Mev En DT2ND BT 0.png

En @ DT2ND ST sim s3 5Mev En DT2ND BT A.png

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