The measurement of the target asymmetry of the reactions {gamma}{ital p}{r_arrow}{pi}{sup +}{ital n} and {gamma}{ital p}{r_arrow}{pi}{degree}{ital p} with the Bonn frozen spin target and the PHOENICS-detector at ELSA
- Physikalisches Institut der Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany)
At the Bonn Electron Stretcher Accelerator ELSA new target asymmetry data for the single pion photoproduction of the reactions {gamma}{ital p}{r_arrow}{pi}{sup +}{ital n} and {gamma}{ital p}{r_arrow}{pi}{degree}{ital p} has been obtained. For the first time a frozen spin target has been used in combination with a tagged photon beam. A simultaneous measurement of both reaction channels in a wide kinematical range of {ital E}{sub {gamma}}=215--950 MeV and {Theta}{sub {ital CMS}{pi}}=35{degree}--135{degree} has been performed at the PHOENICS-detector. Butanol (C{sub 4}H{sub 9}OH) has been used as target material. A proton polarization of more than {plus_minus}90% has been achieved in a polarizing field of 5 Tesla. The data taking has been performed during the frozen spin mode where the polarization has been maintained in a field of 0.35 Tesla. At this field and at temperatures {le}60 mK the proton relaxation time has been in the order of 5 days. The design of the PHOENICS-detector permits a considerable kinematical overdetermination so that the nominal process could be clearly separated from the background. High quality data has been obtained. The systematical error for all data points is {Delta}{ital T}{sub {ital sys}}=2.5%.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 165873
- Report Number(s):
- CONF-9409103-; ISSN 0094-243X; TRN: 96:002515
- Journal Information:
- AIP Conference Proceedings, Vol. 339, Issue 1; Conference: 11. international symposia on high energy spin physics and polarization phenomena in nuclear physics, Bloomington, IN (United States), 15-22 Sep 1994; Other Information: PBD: 15 Jul 1995
- Country of Publication:
- United States
- Language:
- English
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