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
17 nov 08 Expérience de recherche
Tags: BDSIM, borexino, geant4, ilc, LCG/EGEE, MDI, neutrino, polarisation, positron, positrons polarisés, Positrons source, ROOT
