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| | [[Niowave_Report_11-30-2015]] | | [[Niowave_Report_11-30-2015]] |
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| | + | deadline 4/12/16 |
| | + | |
| | + | |
| | + | ==[[Niowave_9-2015]]== |
| | + | ==[[Niowave_10-2015]]== |
| | + | ==[[Niowave_11-2015]]== |
| | + | ==[[Niowave_12-2015]]== |
| | + | ==[[Niowave_1-2016]]== |
| | + | ==[[Niowave_2-2016]]== |
| | + | ==[[Niowave_3-2016]]== |
| | + | ==[[Niowave_4-2016]]== |
| | + | ==[[Niowave_5-2016]]== |
| | + | ==[[Niowave_6-2016]]== |
| | + | |
| | =Task List= | | =Task List= |
| | + | |
| | + | 0.) 34.8 mm pipe, 0.0 -> 0.5 Tesla, E= 6,8,10 MeV. |
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| | 1.) Create a positron (10,000 positrons) and electron event file containing t,x,y,z,Px,Py,Pz for positrons exiting the solenoid and an incident Gaussian beam 1cm in diameter and with a sigma of 1cm. | | 1.) Create a positron (10,000 positrons) and electron event file containing t,x,y,z,Px,Py,Pz for positrons exiting the solenoid and an incident Gaussian beam 1cm in diameter and with a sigma of 1cm. |
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| | =Target thickness optimization= | | =Target thickness optimization= |
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| | + | ==[[PbBi_THickness_CylinderBeam]]== |
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| | ==[[PbBi_THickness_GaussBeam]]== | | ==[[PbBi_THickness_GaussBeam]]== |
| − |
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| − | ==[[PbBi_THickness_CylinderBeam]]==
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| | == [[PbBi_THickness_PntSource]]== | | == [[PbBi_THickness_PntSource]]== |
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| | ===[[PbBi_60cmLong_Solenoid_Collection_Efficiency_2015]]=== | | ===[[PbBi_60cmLong_Solenoid_Collection_Efficiency_2015]]=== |
| − |
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| − | Positron Collection rates with '''60 cm''' long Solenoid
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| − |
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| − | {| border="1"
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| − | | [[File:PositronEventWithSolenoid_09-16-15A.png|200px]] ||[[File:PositronEventWith0.3Solenoid_09-16-15A.png|200px]]
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| − | |-
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| − | | When the solenoid is 1.5 Tesla, a 10 MeV electron produces a 6.5 MeV photon that pair produces a 4.4 MeV positron and a 1 MeV electron || Same Event but this time the solenoid is 0.3 Tesla and the positron hits the beam pipe, annihilates and makes two 511 keV photons
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| − | |+ Sample Positron Production Events
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| − | |}
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| − |
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| − | {| border="1"
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| − | | [[File:PositronEventWithSolenoid_09-16-15B.png|200px]] ||[[File:PositronEventWith0.3Solenoid_09-16-15B.png|200px]]
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| − | |-
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| − | | When the solenoid is set to 1.5 Tesla, a 10 MeV electron produces three photons less than 1 MeV in the target, two of them compton scatter in the beam pipe || The same event but this time the electron produces only 1 photon than ionizes in the target
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| − | |+ Sample Brem event producing no positrons
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| − | |}
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| − |
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| − |
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| − | With SS windows
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| − | Positrons->Draw("sqrt(evt.BeamPosPosX*evt.BeamPosPosX+evt.BeamPosPosY*evt.BeamPosPosY)","evt.BeamPosMomZ>0 && evt.BeamPosPosZ>-500 && sqrt(evt.BeamPosPosX*evt.BeamPosPosX+evt.BeamPosPosY*evt.BeamPosPosY)<97.4/2");
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| − |
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| − |
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| − | {| border="1"
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| − | {| border="1"
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| − | | B-field (Tesla) || || 34.8 mm diameter pipe || 47.5 || 60.2 || 72.9 || 97.4
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| − | |-
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| − | | 0.0 || 0.35 || 1,2,4,4,5 || 2,3,4,4,6 || 4,4,6,7,9 || 6,8,9,10,11 || 16,14,15,16,17
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| − | |-
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| − | | 0.1 || ||225,236,250,246,249=241<math> \pm</math> 10 || 282,282,293,294,306=291<math> \pm</math> 10 || 373,366,370,364,373=369<math> \pm</math> 4 || 451,437,440,438,451=443<math> \pm</math> 7 || 602,584,563,558,570=575<math> \pm</math> 18
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| − | |-
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| − | | 0.3 || 0.35 || 626,619,596,619,611 =614<math> \pm</math> 11|| 720,726,706,730,717=720<math> \pm</math> 9|| 871,864,840,841,834 =850<math> \pm</math> 16|| 987,968,939,943,952 =958<math> \pm</math> 20|| 1118,1106,1069,1067,1080=1088<math> \pm</math> 23
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| − | |-
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| − | | 0.6 || ||929,935,949,969,961=949<math> \pm</math> 17 ||1022,1031,1046,1059,1052 =1042<math> \pm</math> 15 || 1120,1130,1152,1154,1146 =1140<math> \pm</math> 15|| 1168,1184,1210,1221,1206 =1198<math> \pm</math> 21|| 1212, 1218,1240,1254,1242=1233<math> \pm</math> 18
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| − | |-
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| − | | 1.0 || 0.35 ||1117,1085,1083,1061,1085=1086<math> \pm</math> 20 || 1188,1154,1140,1111,1134=1145<math> \pm</math> 28||1225,1190,1178,1149,1172 =1183<math> \pm</math> 28||1243.1208,1195,1164,1184=1199<math> \pm</math> 30|| 1252,1219,1206,1178,1200=1211<math> \pm</math> 27
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| − | |-
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| − | | 1.5 || 0.22 ||
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| − | |-
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| − | | 2.0 || 0.10 ||1198,1210,1215,1223,1176=1204<math> \pm</math> 18 || 1216,1227,1235,1241,1196 =1223<math> \pm</math> 18|| 1237,1243,1252,1257,1214=1241<math> \pm</math> 17|| 1249,1252,1262,1266,1225 =1251<math> \pm</math> 16|| 1257,1262,1270,1276,1234=1260<math> \pm</math> 16
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| − | |-
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| − | | 4.0 || 0.002 ||
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| − | |+
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| − | |}
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| − |
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| − |
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| − |
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| − | {| border="1"
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| − | | [[File:PositronRates-vs-SolenoidField_10-1-15.png |200px]]
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| − | |+ Positron Rates -vs- Solenoid Field for 2mm thick PbBi target and several Beam pipe diameters
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| − | |}
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| | ==Positron & Electron event files== | | ==Positron & Electron event files== |
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| − | Event files were generated assuming an ideal solenoid having an inner radius of 2.527 cm surrounding a beam pipe with a radius of 1.74 cm. Electrons impinge a 2mm thick PbBi liquid target that has a surface area of 2.54 cm x 2.54 cm. Stainless steel windows 0.25 mm thick sandwhich the PbBi target at locations Z= -90.325 and Z= -89.875 cm. The target is located at Z =-90.1 cm and the beam begins 20 cm upstream at Z = -110.1 cm. The incident electron beam is a 0.5 cm radius cylinder.
| + | [[PbBi_PosEventFiles_VaccumGaps_2015]] |
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| − | ===Positrons exiting the Solenoid===
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| − | | |
| − | The solenoid design has changed such that the max field is 0.20 Tesla (0.22) and its length is 150 mm.
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| − |
| + | [[PbBi_PosEventFiles_NoGaps_2016]] |
| − | {| border="1"
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| − | | [[File:TF_Niowave_SolenoidDesign_12-04-15.png | 200 px]] || [[File:TF_LBEtarg1_1-12-16.png | 200 px]]|| [[File:TF_LBEposEvent_1-12-16.png | 200 px]]
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| − | | |
| − | |-
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| − | | Overall Target layout || Closeup of Target Simulation Geometry. The center of the 0.25mm thick stainless steel windows are a distance of 2.25 mm from the center of the LBE target. <math>d_{USS} = d_{DSS} =</math> 2.25 mm, <math>t_{LBE}=2</math> mm, <math>t_{SS} =</math> .25 mm. || An example positron production event. The yellow lines represents a sensitive detector used to record all positron events. The red line represents the incident 10 MeV electron that produces two bremsstrahlung photons shown in green. The first photon has an energy of 2.151 MeV and pair produces in the stainless steel window. The second photon has an energy of 1.393 MeV and exits the system without interacting. The first photon is created at time t= 3.323 ns. The first photon produces a 234.6 keV electron and a 894.2 keV positron at time t=3.336 ns. Only the positron has enough energy to exit the stainless steel window.
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| − | |+ Apparatus
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| − | |}
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| − | In other words I should generate position and momentum files for positrons and electrons at the Z location 15 cm downstream from the middle of the LBE target and within a 3.48 cm diameter beam pipe.
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| − | /vis/viewer/zoom 2
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| − | /gps/pos/centre 0.0 0.0 -150.
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| − | /vis/viewer/panTo -90.1 0 cm
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| − | /vis/viewer/reset
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| − | Twenty (20) million incident electrons with an energy of 10 MeV and forming a cylindrical beam with a 0.5 cm radius cylinder impinged a 2mm thick LBE target located at Z = -106 mm. The Z location of positrons exiting the beam pipe at the end of the 15 cm long solenoid is 44 mm. The positrons are 150.00 mm from the middle of the LBE target (Z=44mm).
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| − | | |
| − | A space delimited text file with the above events in the format of
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| − | | |
| − | PID, x(mm),y,z,Px,Py,Pz(MeV),t(ns)
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| − | | |
| − | in units of cm for distance and MeV for momentum is located at
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| − | | |
| − | for positrons
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| − | | |
| − | http://www2.cose.isu.edu/~foretony/Positrons_2mm10MeVCyl.dat
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| − | | |
| − | and
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| − | http://www2.cose.isu.edu/~foretony/Electrons_2mm10MeVCyl.dat
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| − | | |
| − | The file below contains all the positrons that were created at the target
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| − | | |
| − | format
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| − | | |
| − | | |
| − | A space delimited text file with the above events in the format of
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| − | | |
| − | Initial electron (x,y,z,Px,Py,Pz), Final electron (t,x,y,z,Px,Py,Pz), Positron location after leaving LBE target (t,x,y,z,Px,Py,Pz),Location of positron as it exits a SS window (t,x,y,z,Px,Py,Pz). Units are ns, mm, MeV/c.
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| − | | |
| − | http://www2.cose.isu.edu/~foretony/AllPositrons_2mm10MeVCyl.dat
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| − | | |
| − |
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| − | {| border="1"
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| − | | [[File:PositronTime_1-10-16.png|200px]] ||
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| − | |-
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| − | | Particle flight times for 20 million incident electrons on a 0.2mm thick LBE target with 0.25 mm thick stainless steel windows (no material exists after the last stainless steel window, only vacuum). The time an electron brems in the target (EscatTime) is shown in black. The time a positron is created in the target (PosTime) is shown in blue. The time a positron has traveled 15 cm traversing a uniform 0.2 Tesla Solenoidal field (PosBeamTime) is shown in fuchsia. The field exists throughout the entire world. PosBeamTimeCuts are positrons that are constrained to a beam pipe diameter of 34.8 mm. Positrons are traveling about the speed of light (30 cm/ns) so after 15 cm they arrived 0.5 nsec after the initial electron beam impinges the target.
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| − | |+ Positron Distributions
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| − | |}
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| − | ===Positrons and Electrons after the SS Exit window===
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| − | The same configuration as the previous subsection except that the 1mm thick sensitive detector is placed at
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| − | Z = -100.5 mm. Most of the electrons exit at Z = -100.9 mm.
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| − | | |
| − | A space delimited text file with the above events in the format of
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| − | | |
| − | PID, x(mm),y,z,Px,Py,Pz(MeV),t(ns)
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| − | | |
| − | in units of cm for distance and MeV for momentum is located at
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| − | | |
| − | for positrons
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| − | 23500 Positrons in the file below
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| − | | |
| − | http://www2.cose.isu.edu/~foretony/PositronsAtExitWindow.dat
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| − | | |
| − | | |
| − | and
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| − | 297216 electrons in the file below
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| − | | |
| − | http://www2.cose.isu.edu/~foretony/ElectronsAtExitWindow.dat
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| | ==Solenoid Map== | | ==Solenoid Map== |
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| | ;Conclusion 2 : You loose about 28 +/- 4 % of the positrons in the 0.25 mm thick SS exit window. | | ;Conclusion 2 : You loose about 28 +/- 4 % of the positrons in the 0.25 mm thick SS exit window. |
| | + | |
| | + | =Background studies= |
| | + | |
| | + | ==Brem Spectrum== |
| | + | |
| | + | Below is the photon energy distribution (from Brem & pair production) using a 2mm Pb target for two different incident electron energies; 6 and 10 MeV. The photons are 1 cm downstream of the target and intersection a large forward region. |
| | + | |
| | + | [[File:PbBi_Brem_6-10MeV_4-7-16.png | 200 px]] |
| | + | |
| | + | insert photon spacial distributions |
| | + | |
| | + | Now move the scoring region downstream to a position representing the location of a NaI detector. |
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| | =Beam Line Design= | | =Beam Line Design= |
Development of a Positron source using a PbBi converter and a Solenoid
Conclusions
- A 0.3 (0.6) Tesla Solenoid with a diameter to allow a 9.74 (3.94) cm diameter pipe would collect a positron per thousand incident electrons on a 2mm thick LBE target with 0.25 mm thick SS windows.
- A 15 cm long, 0.2 Tesla solenoid with a 3.94 diameter beam pipe would collect a positron per two thousand electrons impinging a 2mm thick LBE target with 0.25 mm thick SS windows.
- A 4 Tesla Solenoid will remove beam pipe heating from scattered electrons downstream of the target when using a 3.94 cm diameter beam pipe.
Reports
Niowave_Report_11-30-2015
deadline 4/12/16
Task List
0.) 34.8 mm pipe, 0.0 -> 0.5 Tesla, E= 6,8,10 MeV.
1.) Create a positron (10,000 positrons) and electron event file containing t,x,y,z,Px,Py,Pz for positrons exiting the solenoid and an incident Gaussian beam 1cm in diameter and with a sigma of 1cm.
compare distributions with and without solenoid.
2.) Determine the back ground when using a 3.48 diameter beam pipe and Solenoid field of 0.2 for a NaI detector placed at
3.) Experiment, install dipole and solenoid in the tunnel.
Beam Pipe Heating
PbBi_BeamPipeHeatin_2015
Converter target properties
PbBi_NioWave_TargetProperties_2015
Target thickness optimization
Solenoid
Uniform ideal Solenoid
Positron & Electron event files
PbBi_PosEventFiles_VaccumGaps_2015
PbBi_PosEventFiles_NoGaps_2016
Solenoid Map
Inner Radiusu=
Outer Radius =
Length =
Current=
Magnetic Field Map in cylindrical coordinates (Z & R) from Niowave
Rear Window Thickness
Question: Will a thicker downstream exit window increase the positron production efficiency by providing more material for a brehm photon to pair produce in?
Positrons were counted exiting a ideal 0.2 Tesla solenoid that was 15 cm long. A ten MeV electron beam with a 0.5 cm cylindrical radius impinged a 2mm thick PbBi liquid target that had a surface area of 2.54 cm x 2.54 cm. A 0.25 mm thick stainless steel entrance window was used.
Target is at -106 mm, entrance SS window is at -108.25 mm , exit SS window is at -103.75 mm, A sensitive detector for positron is placed at Z= +44mm. The sensitive detector is a cylinder of radius 11.74 cm.
| SS Exit WIndow Thickness (mm) |
Positrons/Million electrons
|
| 0.0 |
1142,1096,1149,1073,1083 = 1109 +/- 35
|
| 0.25 |
774,836,800,785,798 = 798 +/- 23
|
| 0.5 |
693,704,713,697,715 = 704 +/- 10
|
| 1.0 |
587,606,548,592,550 =577 +/- 26
|
- Conclusion 1
- Positron production efficiency improves when the exit window is made thinner
- Conclusion 2
- You loose about 28 +/- 4 % of the positrons in the 0.25 mm thick SS exit window.
Background studies
Brem Spectrum
Below is the photon energy distribution (from Brem & pair production) using a 2mm Pb target for two different incident electron energies; 6 and 10 MeV. The photons are 1 cm downstream of the target and intersection a large forward region.
insert photon spacial distributions
Now move the scoring region downstream to a position representing the location of a NaI detector.
Beam Line Design
PbBi_BeamLine_Elements
goals for JLab
Positrons#Simulations
