Run in GEMC

Since the LUND file is limited to 75000 particles (225000 lines), the gemc will have to be run in batch mode;

11GeV incident electron

Simulating with GEMC

For an incident electron at 11GeV, the Moller electron in the range of 5 to 40 degrees for the scattering angle Theta, has energies lower than 200MeV.

~/src/CLAS/GEMC/experiments/eg12/MolrBckGrd/DV/Isotropic_study/LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut> wc -l LUND_Spread_LH2_IsotropicPhi.LUND 
315000 LUND_Spread_LH2_IsotropicPhi.LUND

Spliting the LUND file into 105 parts of 1000 events, or 3000 lines

split -d -l 3000 -a 3 LUND_Spread_LH2_IsotropicPhi.LUND LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut_

Naming these files LUND files

prename 's/(LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut_\d{3})/$1.LUND/' LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut_*

Placing each of these files into its own directory, within a directory named LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut

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

Defining the gcards

<gcard>

<!-- minumal detectors for HB tracking -->

        <detector name="../../../../../../clas12/fc/forwardCarriage" factory="TEXT" variation="original"/>
        <detector name="../../../../../../clas12/dc/dc"            factory="TEXT" variation="ccdb"/>
        <detector name="../../../../../../clas12/ftof/ftof"            factory="TEXT" variation="java"/>
        <!--option name="SCALE_FIELD" value="clas12-torus-big, -1"/-->


        <option name="OUTPUT" value="evio, LH2_0Sol_0Tor_11GeV_IsotropicPhi_ShieldOut_000.evio"/>

        <option name="ALLRAWS" value="dc"/>
        <!--option name="INTEGRATEDDGT" value="DC"/-->
        <option name="INTEGRATEDRAW" value="dc"/>

        <option name="PHYSICS" value="FTFP_BERT + STD + Optical"/>
        <!--option name="PHYSICS" value="STD"/-->

        <option name="BANK_VERBOSITY" value="1"/>
        <option name="HIT_VERBOSITY" value="1"/>
        <option name="LOG_VERBOSITY" value="1"/>
        <option name="G4TRACK_VERBOSITY" value="1"/>
        <option name="G4P_VERBOSITY" value="1"/>
        <option name="GEN_VERBOSITY" value="1"/>
        <option name="SAVE_ALL_MOTHERS" value="2"/>

<!-- Solenoid apparatus and field -->


        <!--detector name="../../../../../../clas12/magnets/solenoid" factory="TEXT" variation="original"/-->
          <!--option name="HALL_FIELD"  value="clas12-solenoid"/-->

<!-- other CLAS detectors -->

       <detector name="../../../../../../clas12/ec/ec"            factory="TEXT" variation="original"/>
       <detector name="../../../../../../clas12/ctof/ctof"            factory="TEXT" variation="original"/>
       <detector name="../../../../../../clas12/htcc/htcc"            factory="TEXT" variation="original"/>
       <detector name="../../../../../../clas12/pcal/pcal"            factory="TEXT" variation="javageom"/>
       <!--detector name="../../../../../../clas12/micromegas/micromegas"  factory="TEXT" variation="original"/-->


<!-- Beamline material -->
         <!--detector name="../../../../../../clas12/beamline/beamline" factory="TEXT" variation="ft"/-->


</gcard>

Using a file to store the needed commands

/src/CLAS/GEMC/source/gemc -USE_GUI=0 -INPUT_GEN_FILE="LUND,MolTest.LUND" -N=100 eg12.gcard


Solenoid off

~/src/CLAS/coatjava-2.4/bin/clas12-reconstruction -i ../files/MolrBckGrd/Molr.evio -config GEOM::new=true -config MAG::torus=1.0 -config MAG::solenoid=0.0 -o ../files/MolrBckGrd/Molr_rec.evio -s DCHB:DCTB:EC:FTOF:EB -config DATA::mc=true

Solenoid ON


~/src/CLAS/coatjava-2.4/bin/clas12-reconstruction -i ../files/MolrBckGrd/Molr.evio -config GEOM::new=true -config MAG::torus=-1.0 -config MAG::solenoid=1.0 -o ../files/MolrBckGrd/Molr_rec.evio -s DCHB:DCTB:EC:FTOF:EB -config DATA::mc=true -config DCTB::useRaster=true


~/src/CLAS/coatjava-2.4/bin/evio-dump -i ../files/MolrBckGrd/Molr_rec.0.evio

Analyzing Results

Using cat to combine the reconstructed particles found using Analysis.groovy, we can output the particle number from the LUND file, Total Energy, scattering angles Theta, and Phi for the generated and reconstructed particles respectively.

For 0T:

571-1    0.12103204139108564  5.232292493596922       9.99999999997547 0.2397734  64.37257     163.2439
23025-3    0.02376743729734356  11.825408412314742       9.999999999978474 0.29301766  89.180336     -164.40204

For 5T:

24726-1    0.08576327895104396  6.223977074710134       9.99999999997547 0.17311224  20.298353     39.036583
19970-3    0.026540097007028158  11.193535798440614       9.999999999969427 0.15106007  49.16122     14.2969885

Converting the particle number per run into the particle number via the LUND file: Multiplying the line number by 3 accounts for the 3 lines per particle in the LUND file. From this LUND particle we find the weight associated with each particle (Specific Energy and angle Theta). To find the number of particles we can use an awk command:

awk 'NR == 1711 { print $6 }' LUND_Spread.LUND

Moller Electron Weights for 11GeV Incident Electron

Particle number	Run number	LUND Moller electron number	Overall LUND particle number	Corrected LUND header line number	Number of Particles
571	1	571	1713	1711	1097.227223687062
23025	3	69075	207225	207223	25951.273801947842
24726	1	24726	74178	74176	2579.181846387747
19970	3	59910	179730	179728	14255.222465310777

Cross Section

Using the number of expected Moller electrons and the fact that the reaction cross section can be found using the Luminosity we find: Integrating the differential cross-section over the solid angle:

IntegralDiffXSect->Integral()

4.97493824519086629e+04 barns

Multiplying by the Luminosity, we find:

[math]4.97\times 10^{4} barns \times\frac{1.35\times 10^{11}}{barns\cdot s}=6.71\times 10^{15}\frac{electrons}{s}[/math] [math]\Rightarrow \sigma=\int\limits_{\theta=0}^{\pi} \int\limits_{\phi=0}^{2\pi} \left(\frac{d\sigma}{d\Omega}\right)\ \sin{\theta}\,d\theta\,d\phi =\frac{N}{\mathcal L}\equiv total\ scattering\ cross\ section[/math]

Since this is just a ratio of detected particles to total particles, this gives the cross section as a relative probablity of a scattering, or reaction, to occur.

For 0T with 11GeV incident electrons:

[math]\Rightarrow \sigma=\frac{27048}{2.48\times 10^{23}}=1.09\times 10^{-19} barns[/math]

For 5T with 11GeV incident electrons:

[math]\Rightarrow \sigma=\frac{16834}{2.48\times 10^{23}}=6.79\times 10^{-20} barns[/math]

5.5GeV incident electron

For 0T:

16544-1    0.10778422619732184  5.519947956962607       9.999999999974188 0.19995739  25.982777     96.17941

For 5T:

354-1    0.09640233076149667  5.8423283009263045       9.999999999976643 0.09051078  49.163692     -85.56053
5526-4    0.03948624565299794  9.164813676343726       9.999999999971514 0.12387912  52.14526     50.051956
21892-4    0.02741437437384611  11.000629446532491       9.99999999997668 0.26457193  81.77688     179.14293

Moller Electron Weights for 5.5GeV Incident Electron

Particle number	Run number	LUND Moller electron number	Overall LUND particle number	Corrected LUND header line number	Number of Particles
16544	1	16544	49632	49630	814.898350440404
354	1	354	1062	1060	556.656736645754
5526	4	22104	66312	66310	937.328333457728
21892	4	87568	262704	262702	8343.893471134810

MolThetaLabweighted->Integral()

This gives about 4.96e+23 incident electrons

For 0T with 5.5GeV incident electrons:

[math]\Rightarrow \sigma=\frac{814}{4.96\times 10^{23}}=1.64\times 10^{-21} barns[/math]

For 5T with 5.5GeV incident electrons:

[math]\Rightarrow \sigma=\frac{9838}{4.96\times 10^{23}}=1.98\times 10^{-20} barns[/math]