Difference between revisions of "G4Beamline PbBi"

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[[PbBi_BeamLine_Elements]]
 
[[PbBi_BeamLine_Elements]]
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=goals for JLab=
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 +
  
 
[[Positrons#Simulations]]
 
[[Positrons#Simulations]]

Revision as of 20:08, 14 May 2015

Development of a Positron source using a PbBi converter and a Solenoid

Converter target properties

Definition of Lead Bismuth


1cm diameter target 2 mm thick PbBi

0.5 Tesla solenoid


Desire to know

Emmittance (mrad * mm)

dispersion (Delta P/P) (mradian/1000th mm/1000th)

of electrons after the PbBi target.


pole face rotation in vertical plane.

G4BeamLine and MCNPX

Target thickness optimization

PbBi_THickness_GaussBeam

Dmitry's processing of Tony's GEANT simulations showing transverse phase space portrait (left) and longitudinal phase space portrait (right). Phase space portraits show coordinate x or y vs diveregense=px/pz or py/pz (or time vs kinetic energy ). Captions show:

1. geometric (not normalized) emittance for transverse and emittance for longitudinal phase space portraits (ellipse areas divided by "pi")

2. Twiss parameters

3. Ellipse centroid for longitudinal phase portrait

4. sqrt(beta*emittance) and sqrt(gamma*emittance) - half sizes of the projections of the ellipses on the coordinate and divergence axes respectively.

Electrons - RMS

Ed1.png

Electrons - 68.2% core

Ed2.png

Positrons - RMS

Pd1.png

Positrons - 68.2% core

Pd2.png

PbBi_THickness_CylinderBeam

Dmitry's processing of Tony's GEANT simulations showing transverse phase space portrait (left) and longitudinal phase space portrait (right). Phase space portraits show coordinate x or y vs diveregense=px/pz or py/pz (or time vs kinetic energy ). Captions show:

1. geometric (not normalized) emittance for transverse and emittance for longitudinal phase space portraits (ellipse areas divided by "pi")

2. Twiss parameters

3. Ellipse centroid for longitudinal phase portrait

4. sqrt(beta*emittance) and sqrt(gamma*emittance) - half sizes of the projections of the ellipses on the coordinate and divergence axes respectively.

Electrons - RMS

E1.png

Electrons - 68.2% core

E2.png

Positrons - RMS

P1.png

Positrons - 68.2% core

P2.png

PbBi_THickness_PntSource

Energy Deposition in Target system (Heat)

Layout.png

ElectronTracks.pngPhotonTracks.png

ElectronEnergy.pngPhotonEnergy.png

MCNPX simulations of energy deposition into different cells are below. There is a slight overestimate (they add up to about 120%). Positrons contribute less than 1% of electrons' contribution. No magnetic filed is assumed.

Model.png

Tablen1.png

Tablen2.png

2mm thick PbBi, 10 MeV, point source

G4beamline pencil beam 10 cm radius

beam ellipse particle=e- nEvents=1000000 beamZ=0.0 beamX=0. beamY=0. \
        sigmaX=10.0 sigmaY=10.0 sigmaXp=0.000 sigmaYp=0.000 \
      meanMomentum=10. sigmaE=0. maxR=10.
PbBi Thickness (mm) #positrons/million electrons (G4Beamline) #positrons/million electrons (MCNPX)
1 1091
1.5 1728
2 1902[math]\pm[/math] 43 1984
2.5 2062
3 [math]\pm[/math] 13 1986
3.5 1938
4 [math]\pm[/math] 39 1858
5 1646
6 [math] \pm[/math] 37 1541
10 1216

Solenoid

Inner Radiusu=

Outer Radius =

Length =

Current=

Magnetic Field Map in cylindrical coordinates (Z & R) from Niowave

Beam Line Design

PbBi_BeamLine_Elements

goals for JLab

Positrons#Simulations