Difference between revisions of "G4Beamline PbBi"

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[[File:Tablen2.png| 200 px]]
 
[[File:Tablen2.png| 200 px]]
 
=== 2mm thick PbBi, 10 MeV,  point source===
 
G4beamline pencil beam 10 cm radius
 
<pre>
 
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.
 
</pre>
 
 
{| border="1"
 
| 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==
 
==Solenoid==

Revision as of 22:49, 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

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