Pair-Polarimeter for High Energy Protons
The angle correlation in e{sup +}e{sup {minus}} pair production by linear polarized photon was proposed for photon polarization measurements by Yang and Berlin and Madansky. An accurate QED calculation with analysis of the possible experimental setup was done by L Maximon and H. Olsen. The effect was used successfully for measurement of the beam polarization. The limitation of the method at photon energies above 100 MeV arises from the small value of an angle between pair components. They propose a new polarimeter for high energy photons based on the well known correlation in electron-positron pair production from an amorphous converter. The detector design utilizes silicon micro-strip detectors that allow the construction of a compact device useful in the few GeV photon energy range. The most important features of these detectors are the capability to detect two tracks separated by a very small distance ({approximately} 100 microns) and very good position resolution, ({approximately} a few microns). Because the typical opening angle in e{sup +}e{sup {minus}} pair is about 1/{gamma} and available space for a polarimeter is about 1 meter, the distance e{sup +}e{sup {minus}} is about a fraction of mm. It means that at the photon energies of interest, most of pairs have a distance e{sup +}e{sup {minus}} much larger than the micro strip detector limitation.
- Research Organization:
- Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC05-84ER40150
- OSTI ID:
- 774727
- Report Number(s):
- JLAB-PHY-01-04; DOE/ER/40150-1804
- Country of Publication:
- United States
- Language:
- English
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