DV RunGroupC Moller

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

Simulating the Moller scattering background for EG12

GEANT4 Simulation of Moller Events

Simulation Setup

Determine the Moller background using an LH2 target to check the physics in GEANT4

Comparing experimental vs. theoretical for Møller differential cross section 11GeV

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

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

Cover Full Solid Angle of Detector

Check Differential Cross-Section

It was shown earlier that the differential cross section scale is [math]\frac{d\sigma}{d\Omega}\approx 16.2\times 10^{-2}mb=16.2\mu b[/math]

For an Ammonia target:

[math]\rho_{target}\times l_{target}=\frac{.8 g}{1 cm^3}\times \frac{1 mole}{17 g} \times \frac{6\times10^{23} atoms}{1 mole} \times \frac{1 cm}{ } \times \frac{10^{-24} cm^2}{barn} =2.82\times 10^{-2} barns[/math]

If the beam had 4E9 incident electrons, the differential cross-section would be found with,

[math]\frac{1}{\rho_{target}\times l_{target} \times 4\times 10^9}=8.87\times 10^{-9} barns=.00887 \mu b[/math]

Since extra Phi angles have been produced obviously a larger number of incident electrons would be needed. Looking at the number Moller events are created for 1E6, 1E7, and 4E9 incident electrons, we can estimate the number of incident electrons needed for the number of extra Phi angles produced.

Moller Events per Incident Electrons

# of Incident Electrons	# of Moller Events	# of E>500MeV
1e6	38343	134
1e7	383633	1490
4e9	12444898	48548

This shows a trait of providing around 100 Moller electrons of Energy greater that 500 MeV for about 1 million incident electrons of Energy 11 GeV. Since the boosting of the number of Phi angles leaves around 4431573 Moller electrons with Energy greater than 500 MeV, this would imply around 4e10 incident electrons of Energy 11 GeV.

Using the same expression, but this time for 4e10 incident electrons,

[math]\frac{1}{\rho_{target}\times l_{target} \times 4\times 10^{10}}=8.87\times 10^{-10} barns=.000887 \mu b[/math]

Rebining the histogram to account for the unequal weighting of the bins outlined in the table above

TH1F *Combo=new TH1F("TheoryExperiment","Theoretical and Experimental Differential Cross-Section CM Frame",360,90,180);
Combo->Add(MolThetaCM,8.87e-10);
Combo->Draw();
Double_t Bins[16]={90,100,110,120,130,135,140,142,144,146,148,150,152,154,156,180};
hnew=Combo->Rebin(15,"hnew",Bins);
hnew->Draw();
Theory->Draw("same");

Running LUND files in GEMC

Since the LUND file is limited to 75000 lines, the gemc will have to be run in batch mode;

Creating a batch directory, with two subdirectories; 1)Phi_Parts, 2)submit.

1)Once the LUND file is broken into 178 parts, they can have the LUND extension added by:

prename 's/(Phi_Parts_\d{4})/$1.LUND/' Phi_Parts_*

Placing each of these files into its own directory, within a directory named Phi_Parts

find . -name "*.LUND" -exec sh -c 'mkdir "${1%.*}" ; mv "$1" "${1%.*}" ' _ {} \;

2)Creating the submit directory, and using a c++ program, creating the needed 178

#include <iomanip>
#include <sstream>
#include <iostream>
#include <fstream>

using namespace std;

void submit() {

        for(int a=0;a<2;a++)
        {
                for(int b=0;b<10;b++)
                {
                        for(int c=0;c<10;c++)
                        {
                                string filename="submit0";
                                stringstream hundreds;
                                        hundreds << a;
                                stringstream tens;
                                        tens << b;
                                stringstream ones;
                                        ones << c;
                                string fullname="";
                                fullname=filename + hundreds.str() + tens.str() + ones.str();
                        //              cout << fullname << "\n";
                        
                                ofstream myfile;
                                myfile.open(fullname.c_str());
                                
                                
                                myfile << "#!/bin/sh\n";
                                myfile << "#PBS -l nodes=1\n";
                                myfile << "#PBS -A FIAC\n";   
                                myfile << "#PBS -M vanwdani@isu.edu\n";
                                myfile << "#PBS -m abe\n";
                                myfile << "#\n";
                                myfile << "cd /home/lds/src/CLAS/GEMC\n";
                                myfile << "tcsh\n";
                                myfile << "source setup\n";
                                myfile << "cd /home/lds/src/GEANT/geant4.9.6/geant4.9.6-install/bin/geant4.sh\n";
                                myfile << "cd /home/vanwdani/src/GEANT4/geant4.9.6/Simulations/Research/Moller/batch/Phi_Parts/Phi_Parts_0";
                                        myfile <<a<<b<<c<<"\n";
                                myfile << "gemc -USE_GUI=0 -Hall_Material=\"Vacuum\" -INPUT_GEN_FILE=\"LUND, Phi_Parts_0";
                                        myfile <<a<<b<<c;
                                        myfile << ".LUND\" -N=75000 eg12.gcard\n";
                                myfile << "~/src/CLAS/coatjava-1.0/bin/clas12-reconstruction -i eg12.ev -config DCHB::torus=1.0 ";
                                        myfile << "-config DCHB::solenoid=0.0 -config DCTB::kalman=true -o eg12_rec.ev  -s DCHB:DCTB:EC:FTOF:EB\n";
                                myfile << "~/src/CLAS/coatjava-1.0/bin/rungroovy Analysis.groovy eg12_rec.0.evio\n";
                                
                                
                                myfile.close();
                        }
                }
        }
         
}

This creates the submitXXXX file

#!/bin/sh
#PBS -l nodes=1
#PBS -A FIAC
#PBS -M vanwdani@isu.edu
#PBS -m abe
#
cd /home/lds/src/CLAS/GEMC
tcsh
source setup
cd /home/lds/src/GEANT/geant4.9.6/geant4.9.6-install/bin/geant4.sh
cd /home/vanwdani/src/GEANT4/geant4.9.6/Simulations/Research/Moller/batch/Phi_Parts/Phi_Parts_0000
gemc -USE_GUI=0 -Hall_Material="Vacuum" -INPUT_GEN_FILE="LUND, Phi_Parts_0000.LUND" -N=75000 eg12.gcard
~/src/CLAS/coatjava-1.0/bin/clas12-reconstruction -i eg12.ev -config DCHB::torus=1.0 -config DCHB::solenoid=0.0 -config DCTB::kalman=true -o eg12_rec.ev  -s DCHB:DCTB:EC:FTOF:EB
~/src/CLAS/coatjava-1.0/bin/rungroovy Analysis.groovy eg12_rec.0.evio

Creating a file named lds-submit

---

Back to Recon

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