G4Beamline PbBi

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

Energy Deposition in Target system (Heat)

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.

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

Positrons#Simulations