Difference between revisions of "2012AnnihCountrRateEstimate"
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The photon rates predicted by GEANT4 when electrons and positrons interact with the ChroMox target and enter one of the NaI detectors haing a solid angle of (0.27 strad) | The photon rates predicted by GEANT4 when electrons and positrons interact with the ChroMox target and enter one of the NaI detectors haing a solid angle of (0.27 strad) | ||
− | Integrating | + | |
+ | Integrating between 0.5 and 0.53 MeV (511 peak unclear) | ||
+ | |||
+ | :<math>\frac{\mbox{Positrons}}{\mbox{electron}} = \frac{1094}{8.4} = \frac{130}{1}</math> | ||
+ | |||
Revision as of 16:41, 2 February 2012
Rate Estimates
Previous experiment at the IAC
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IAC apparatus for positron production experiment | Counts observed when the dipole is tuned to direct positrons onto the Ta target | Counts from electrons on Ta target |
- HpGe observed about 1 annihilation photon per 10 microCoulombs of electrons on the upstream Tungsten target
- Ratio of annihilation photons observed when using positrons to electrons 120 to 10
Condition | Grade Calculation |
Electron Beam Energy | 10 MeV |
Peak current | 40 mA |
Pulse width | 100 ns |
Rep Rate | 300 Hz |
NaI rate Ratio of positron to electron beam
Assumed Geometry
Assume a 2 mm thick Tungsten target that is 1" square
The target is located at -80 < Z < -80.2
The NaI crystal is 2.32" or 56.49 mm in diameter
The NaI crystal is 8" from the target then the opening angle is atan(2.32/8/2) = 8.25 degrees
Solid Angle
Chromox target
Chromox target is 0.011" thick = 0.279 mm
File:Chromox datasheet CERN.pdf
Rates using GEANT4
2 mm Thick Tungsten annihilation target
Integrating between 0.3 and 0.7 MeV (511 peak unclear)
Integrating between 0.5 and 0.53 MeV (511 peak unclear)
- Experiment at IAC had
Chromox
The photon rates predicted by GEANT4 when electrons and positrons interact with the ChroMox target and enter one of the NaI detectors haing a solid angle of (0.27 strad)
Integrating between 0.5 and 0.53 MeV (511 peak unclear)