Difference between revisions of "DV RunGroupC Moller"

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<center><math>E\approx 53 MeV</math></center>
 
<center><math>E\approx 53 MeV</math></center>
  
  Since the Energy in the CM frame is equal, we should be able to cycle through the scattering angle theta to obtain the differential cross-section
+
 
 +
Since the Energy in the CM frame is equal, we should be able to cycle through the scattering angle theta to obtain the differential cross-section
 +
 
  
 
===[[Uniform distribution in Energy and Theta LUND files]]===
 
===[[Uniform distribution in Energy and Theta LUND files]]===

Revision as of 18:27, 6 September 2016

need to insert moller shielding into card after moller LUND file is created. (see clas12/beamline)

Simulating the Moller scattering background for EG12

Moller Differential Cross-Section

GEANT4 Simulation of Moller Events

Simulation Setup

Use GEANT4 via GEMC to estimate the Moller background for electron scattering experiments in JLab's Hall B. The first step towards this goal is to use GEANT4 without the GEMC infrastructure to create event (LUND) files that will be used as input events for GEMC.

Benchmark GEANT4's Moller scattering prediction with the theoretical cross section using LH2

Comparison of simulation vs. the theoretical Møller differential cross section using 11 GeV electrons impinging LH2

Converting the number of scattered electrons per scattering angle theta to a differential cross-section in barns.

Experimental and Theoretical Moller Differential Cross-Section in Center of Mass Frame Frame
Figure 5c: The experimental and theoretical Moller electron differential cross-section for an incident 11 GeV(Lab) electron in the Center of Mass frame of reference.

Change to a NH3 Target

Replacing the LH2 target with an NH3 target

Benchmark GEANT4's Moller scattering prediction with the theoretical cross section using NH3

Comparison of simulation vs. the theoretical Møller differential cross section using 11 GeV electrons impinging NH3

Converting the number of scattered electrons per scattering angle theta to a differential cross-section in barns.

Theoretical and Simulated Moller Differential Cross-Section in Center of Mass Frame Frame
Figure 5c: The theoretical and simulated Moller electron differential cross-section for an incident 11 GeV(Lab) electron in the Center of Mass frame of reference for NH3 target.

LH2 Vs. NH3

Benchmark GEANT4's Moller scattering prediction for NH3 and LH2

Effects Due to Target Material

Target Density

Atomic Mass and Electron Number Effects

Differential Cross-Section Offset

Theoretical and Simulated Moller Differential Cross-Section in Center of Mass Frame Frame
Figure 5c: The theoretical and simulated Moller electron differential cross-section for an incident 11 GeV(Lab) electron in the Center of Mass frame of reference for NH3 target. The theoretical differential cross-section has been adjusted to account for the 10 electrons within NH3.

ROOT Macro to read LUND files and make plots


LUND MolMomCM.pngLUND MolThetaCM.png


LUND MolMomLab.pngLUND MolThetaLab.png


Run the above theta and E distribution of Mollers through GEMC with and without Solenoid on.  Determine the Theta and E range of Mollers that enter the detector.


Scanning from 2MeV to 5500MeV, and 0 to 36 degrees in Theta.

For Solenoid on with 5T:

<gcard>

        <detector name="../../../../../clas12/fc/forwardCarriage" factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/dc/dc"            factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/ec/ec"            factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/ctof/ctof"            factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/ftof/ftof"            factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/htcc/htcc"            factory="TEXT" variation="original"/>
        <detector name="../../../../../clas12/pcal/pcal"            factory="TEXT" variation="original"/>
        <option name="BEAM_P"   value="e-, 2.800*GeV, 18.0*deg, 10*deg"/>
        <option name="SPREAD_P" value="2.798*GeV, 18*deg, 180*deg"/>
        <option name="SCALE_FIELD" value="clas12-torus-big, -1.0"/>
        <option name="HALL_FIELD"  value="clas12-solenoid"/>
        <option name="SCALE_FIELD" value="clas12-solenoid, 1.0"/>
        <option name="OUTPUT" value="evio,eg12.ev"/>

</gcard>

Using the standard commands for gemc

gemc -USE_GUI=0 -N=1000 eg12_sol.gcard
~/src/CLAS/coatjava-1.0/bin/clas12-reconstruction -i eg12.ev -config DCHB::torus=-1.0 -config DCHB::solenoid=1.0 -config DCTB::kalman=true -o eg12_rec.ev -s DCHB:DCTB:EC:FTOF:EB
~/src/CLAS/coatjava-1.0/bin/run-groovy Analysis.groovy eg12_rec.0.evio


Checking for a reconstructed particle that undergoes a phi shift where the 1st column is energy and the 2nd the scattering angle theta:

For Energy:
awk 'NR == 1 {line =$0; min =$2} NR >1 && $2 < min {line =$0; min = $2} END{print line}' Energy_Phi_Shift.dat
289     0.6624017631112946      33.37507824033966       -179.63657653407975     0.7254709       29.696417       -177.79057      473.36051689004984      11.978802748439216      -129.55774724876173


awk 'NR == 1 {line =$0; max =$2} NR >1 && $2 > max {line =$0; max = $2} END{print line}' Energy_Phi_Shift.dat
978     5.584765946130235       24.90893565820338       -170.69784116534063     5.593401        24.90894        -170.65994      472.16552666546283      23.31807917059094       -165.11125601370114

For Theta:
awk 'NR == 1 {line =$0; min =$3} NR >1 && $3 < min {line =$0; min = $3} END{print line}' Energy_Phi_Shift.dat
12      4.83485521395583        10.577021312967325      -50.86708775351051      4.8205996       10.617784       -50.895683      491.627055439108        5.9032309421001985      -43.82964507576243

awk 'NR == 1 {line =$0; max =$3} NR >1 && $3 > max {line =$0; max = $3} END{print line}' Energy_Phi_Shift.dat
187     1.3382869250001856      35.63598792463312       29.887530073265214      1.3481133       35.449417       30.009071       472.455052447561        19.034043420497742      55.20328358414997


Similarly for 0T:

For Energy:
awk 'NR == 1 {line =$0; min =$2} NR >1 && $2 < min {line =$0; min = $2} END{print line}' Energy_Phi_Shift.dat
148     0.36418038435234207     33.68296595663359       -175.89942431595827     0.35383263      51.743824       -39.45801       469.5694572319308       24.353383233947522      -176.27025218702502


awk 'NR == 1 {line =$0; max =$2} NR >1 && $2 > max {line =$0; max = $2} END{print line}' Energy_Phi_Shift.dat
818     5.5278794590742235      12.937136966282836      -43.35663621477178      5.539351        12.95216        -49.09295       484.8800252169308       8.27731670021694        -43.245753766203364

For Theta:
awk 'NR == 1 {line =$0; min =$3} NR >1 && $3 < min {line =$0; min = $3} END{print line}' Energy_Phi_Shift.dat
559     4.909449160222199       9.918634647646794       0.06548256930681198     4.914272        9.938521        -5.861595       492.1448533455858       7.501204563534799       -0.006721611135017764

awk 'NR == 1 {line =$0; max =$3} NR >1 && $3 > max {line =$0; max = $3} END{print line}' Energy_Phi_Shift.dat
326     1.272966353429713       35.731680814303196      85.3173707349696        1.2830343       38.27654        58.368687       483.4835073848272       3.950855595379657       83.87603767806992

Reconstruction of Moller Events

The LUND format

Writing LUND files

Running GEMC

Phi Shift observation using DC hit Reconstruction Data

Gcard creation defining energy and angle range of electrons

Modified gcards

Effects of Solenoid on Electrons

Results for defined distribution in Solenoid Fields

Results for Random Spread of Energy and angle theta in the Lab frame

Cover Full Solid Angle of Detector

Using GEANT simulation data

Calculations of 4-momentum components

Alter Phi Angles

Check Differential Cross-Section

Using Isotropic spread in Theta and Energy for Set Angle Phi

Since the Differential Cross-Section for Moller scattering is well known in the center of mass frame of reference, a conversion to the detector's lab frame of reference will need to occur. To ensure that the GEMC detector is fed a Moller LUND file for the differential cross section, the center of mass frame LUND information must be converted to the lab frame equivalent. Using the expression for the differntial cross-section:

[math]\frac{d\sigma}{d\Omega}=\frac{ \alpha^2 }{4E^2}\frac{ (3+cos^2\theta)^2}{sin^4\theta}[/math]

where,

[math]\alpha ^2=5.3279\times 10^{-5}[/math]


[math]E\approx 53 MeV[/math]


Since the Energy in the CM frame is equal, we should be able to cycle through the scattering angle theta to obtain the differential cross-section


Uniform distribution in Energy and Theta LUND files

Reading LUND files

Run in GEMC

Detector Occupancy

clas12->Draw("Detector.wire:Detector.layer>>(7,1,7,120,0,120)","Detector.superlayer<3","colz")

Gcard settings

Verfication of Mother/Daughter Occupancy

Benchmark GEMC Occupancy Prediction for 11GeV Electron Beam with 0T Solenoid for LH2

Setup for Batch Job With Varying Experimental CLAS12 Quantities

Run Occupancy for Sector 1 DC hits

Papers used

[1]Farrukh Azfar's Derivation of Moller Scattering

File:FarrukAzfarMollerScatter.pdf

A polarized target for the CLAS detector

File:PHY02-33.pdf

An investigation of the spin structure of the proton in deep inelastic scattering of polarized muons on polarized protons

File:1819.pdf

QED Radiative Corrections to Low-Energy Moller and Bhabha Scattering

http://arxiv.org/abs/1602.07609



EG12