Difference between revisions of "2012AnnihCountrRateEstimate"
Jump to navigation
Jump to search
| Line 60: | Line 60: | ||
Integrating between 0.3 and 0.7 MeV (511 peak unclear) | Integrating between 0.3 and 0.7 MeV (511 peak unclear) | ||
| − | :<math>\frac{\mbox{Positrons}}{\mbox{electron}} = \frac{ | + | :<math>\frac{\mbox{Positrons}}{\mbox{electron}} = \frac{6768}{1367} = \frac{5}{1}</math> |
[[Image:G4AnihCountrRates_02022012.png | 200px]] | [[Image:G4AnihCountrRates_02022012.png | 200px]] | ||
Revision as of 16:31, 2 February 2012
Rate Estimates
Previous experiment at the IAC
 |
 |
|
| 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
Tungsten
Integrating between 0.3 and 0.7 MeV (511 peak unclear)
Chromox
The photon rates produced 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)
