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

G4BeamLine and MCNPX

Target thickness optimization

First simple test is to send 1 million, 10 MeV electrons towards a PbBi target and count how many positrons leave the downstream side

The Random number seed is set by Time in G4beamline to use a different set of pseudo random numbers each time it is run

The G4Beamlin incident electron beam has the following properties

beam gaussian particle=e- nEvents=1000000 beamZ=0.0 
        sigmaX=1.0 sigmaY=1.0 sigmaXp=0.100 sigmaYp=0.100 
        meanMomentum=10.0 sigmaP=4.0 meanT=0.0 sigmaT=0.0

PbBi Thickness (mm)	#positrons/million electrons (G4Beamline)	#positrons/million electrons (MCNPX)
1	960,874, 916	1091
1.5	1508
2	1963,1919,1880,1877,1970 = 1902 [math]\pm[/math] 43	1984
2.5	1997
3	2233,2250, 2251,2226 , 2222=2236 [math]\pm[/math] 13	1986
3.5	2193
4	2184,2156,2089,2173,2181=2157 [math]\pm[/math] 39	1858
5	2042	1646
6	1851	1541
10	1480	1216

Energy Distribution

Angular distribution of positrons

Solenoid

Positrons#Simulations