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

Journal Article · Sat Jul 15 04:00:00 EDT 1995 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.48625· OSTI ID:165873

Dutz, H ^[1]

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1. 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--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 339; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ANGULAR DISTRIBUTION
HYDROGEN 1 TARGET
MEV RANGE 100-1000
NEUTRONS
PARTICLE PRODUCTION
PHOTONUCLEAR REACTIONS
PIONS NEUTRAL
PIONS PLUS
POLARIZATION-ASYMMETRY RATIO
POLARIZED TARGETS
PROTONS