17 juil 09 Hybrid source @ 8GeV: particles distributions after the crystal and after the amorphous
A 8 GeV electrons beam (composed by 1.1e+4 particles) impinge on a <111> oriented tungsten crystal of 1mm thickness.
Particles at the exit of the crystal
For display reason a cut is apply on px and py value (abs(px&&py)<20 MeV/c).
First case a transverse distribution of sigma=1mm is added to the particles transverse distribution
Electrons phase space at the exit of the crystal
Photons phase space at the exit of the crystal
Positrons phase space at the exit of the crystal
Second case a transverse distribution of sigma=2.5mm is added to the particles transverse distribution
Electrons phase space at the exit of the crystal
Photons phase space at the exit of the crystal
Positrons phase space at the exit of the crystal
Particles at the exit of the amorphous
The photons at the exit of the crystal is use to impinge on 8mm amorphous tungsten
(for 2.5mm rms value)
After the amorphous px,py and pz are defined by the following
Photons phase space at the exit of the amorphous
Electrons phase space at the exit of the amorphous
Positrons phase space at the exit of the amorphous
Tags: channeling, hybrid source, positron source
14 avr 09 Production of positron using gamma from Bremsstralhung
A 10GeV mono energetic electron beam (with au gaussian distribution in x and y
-in root : gRandom->Gaus(0,2.5e-3)/sqrt(2.)-) impinging on 0.1 cm amorphous tungsten produced gamma with this phase space (yield=#gamma/#e-=138966/50000~2.78)
Gamma energy distribution
X distribution
Y distribution
Those gamma are using to produce positron by impinging on 0.8 cm of amorphous tungsten
(distance between the two amophous target is 2m).
Positron phase space distribution(yield=#positron/#electron=143443/50000 ~2.86)
Energy distribution
X distribution
Y distribution
Momentum in X distribution
Momentum in Y distribution
Momentum in Z distribution
Tags: bremsstralhung, positron
01 avr 09 Hybrid source: positrons distribution
(Robert Chehab’s graphic and summary)
In the following we took:
For both case (10 GeV and 5 GeV) the inital x and y electron distribution follow (ROOT syntax)
x=gRandom->Gaus(0,2.5e-3)/sqrt(2.); // gaussian centered x=0 with rms_x=2.5mm y=gRandom->Gaus(0,2.5e-3)/sqrt(2.); // gaussian centered y=0 whith rms_y=2.5mm
Electron beam energy : 10 GeV
- Crystal thickness : 0.1 cm
- Distance between amorphous and amorphous : 2m
- Amorphous thickness : 0.8 cm
(initial particles impinging on the crystal = 5000 macro e-)
Photons energy spectrum
Positrons phase space after the amorphous target
Energy (no energy cut)
Energy (below 400 MeV):
X:
Y:
Px:
Py:
Positrons spatial distribution after capture section (AMD)
AMD caracteristics
Transverse phase space of the positrons from the target.
We apply a cut in the radius, r<20mm corresponding to the aperture of the
pre-accelerating cavities.
In blue after the amorphous and in red after the AMD
Angle distribution
Electron beam energy : 5GeV
- Crystal thickness : 0.14 cm
- Distance between amorphous and amorphous : 2m
- Amorphous thickness : 1 cm
(initial particles impinging on the crystal = 6000 macro e-)
Photons energy spectrum
Positrons phase space after the amorphous target
Energy (no energy cut):
Energy (below 200 MeV):
X:
Y:
Px:
Py:
Positrons spatial distribution after capture section (AMD)
AMD caracteristics
Transverse phase space of the positrons from the target.
We apply a cut in the radius, r<20mm corresponding to the aperture of the
pre-accelerating cavities.
In blue after the amorphous and in red after the AMD
Angle distribution
EXTRA …
(thanks to Laurent Garnier Qt implementation see http://users.lal.in2p3.fr/garnier/G4QtTutorial.html#interface)
Tags: AMD, channeling, hybrid source, positron
17 fév 09 Production of polarised positron using Bremsstralhung
Initial parameters :
- e- beam 80-50 MeV normal incidence, stat. 10^6
- 100% longitudinal electron polarisation S(0,0,1)
- Tungsten target of 1×X0 = 3.5 mm (Z=74, ρ = 19.3 g/cm3)
Positron Yield = Ne+/Ne- ~ 15 %
Energy deposited in the tungsten target per initial incident electron ~ 14 MeV
Mean positron polarisation : Sz ~ 30 %
Modification of the positron yield, positron polarisation considering differents target thickness and
two differents inital electron energy (50 MeV and 80 MeV)
Initial electron energy 50 MeV
Positron Yield versus target thickness (different energy selection are shown)
Mean positron energy versus target thickness (different energy selection are shown)
Positron polarisation versus target thickness (different energy selection are shown)
Initial electron energy 80 MeV
Positron yield versus target thickness (different energy selection are shown)
Mean positron energy versus target thickness (different energy selection are shown)
Positron polarisation versus target thickness (different energy selection are shown)
Statics studies
Tags: bremsstralhung, positron, positron polarisation
22 jan 09 Interaction e- et gamma de 100 MeV sur Tungsten
J’ai cherché désespérément ces informations pour cross checker ma simulation Geant4:
Nombre particules secondaires créées et leur pertes d’énergie dans la cible.
Taille de la cible de Tungsten(G4_W densité 19.3 g/cm3) 3.5mm (*20cm*20cm)
Uniquement les processus EM pris en compte pas de flag hadronique i.e pas de création de neutrons
1) Run 10000 gamma de 100 MeV
Gamma
Mean Number per Event : 3.127400
Mean Kinetic Energy : 22.142556 MeV +- 37.196105 MeV
Energy deposited in the target per incident particles 0.133872 MeV
Electrons
Mean Number per Event : 0.406800
Mean Kinetic Energy : 30.026098 MeV +- 24.451613 MeV
Energy deposited in the target per incident particles 3.404414 MeV
Positron
Mean Number per Event : 0.366600
Mean Kinetic Energy : 33.335758 MeV +- 23.974807 MeV
Energy deposited in the target per incident particles 2.190985 MeV
Soit 5.73 MeV déposée dans la cible de tungstène par gamma incident
2) Run 10000 e- de 100 MeV
Gamma
Mean Number per Event : 6.670000
Mean Kinetic Energy : 7.301013 MeV +- 13.162204 MeV
Energy deposited in the target per incident particles 0.345439 MeV
Electrons
Mean Number per Event : 1.068500
Mean Kinetic Energy : 31.868788 MeV +- 24.521092 MeV
Mean Polarization :0.000000 +- 0.000000
Energy deposited in the target per incident particles 12.372011 MeV
Positron
Mean Number per Event : 0.183000
Mean Kinetic Energy : 14.930346 MeV +- 13.545201 MeV
Energy deposited in the target per incident particles 1.234059 MeV
Soit 14 MeV déposée dans la cible de tungstène par e- incident
Tags: pedd, production positrons, tungsten
