The E166 Spectrometer.
Positron tracks visualization under MERMAID field map μ=4 "using Wired3".
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Animated top and perspective views are under (click on the links below)
Top View (Anim) | Perspective View (Anim) |
Track visualisation ( click on the below)
500 events | 1000 events | 2000 events | 4000 events | 8000 events | 16000 events. |
Relevant Parameters for the present simulation study (E166_G4_SIM) |
Material and values |
Positron energy |
Uniform distribution [0 , 8.3] MeV. |
positron beam shape at the conversion target |
Disk 3 mm radius. |
Positron (angular distribution) |
Uniform in cos(ө) [0.99, 1] and Uniform in phi [0, 2π]. |
Reconversion target Material |
Tungsten (W). |
Reconversion target Thickness |
0.5 X0. |
Reconversion target radius. |
Radius = 25 mm |
Vacuum (vacuum chamber) |
3E-18 Pascal |
Vacuum chamber inner space |
(H, L, W) 54 , 156, 132 mm fort the small chamber (H, L, W) 54, 334, 188 mm for the big chamber |
Entrance of the spectrometer. |
Radius = 18.255 mm |
Exit of spectrometer. |
Radius = 23 mm |
Jaws (momentum slit) |
Maximum Opening at 30 mm |
Distance (exit of spectrometer-reconversion target) |
182.4 mm |
Spectrometer magnetic field. |
Alexander’s MERMAID calculation ( μ =4 ). |
3D linear interpolation |
Unitary cube method (3D local linear interpolation) |
G4 tracking in a magnetic field “step length “ |
100 μm |
Table 1: The most relevant parameters for the present Geant4 simulation study. |
Karim Laihem, DESY Zeuthen, June 20th 2006. |