Magnetic-field dependence of the signal of a uranium-scintillator calorimeter

The magnetic-field dependence of the signal from 3 GeV electrons and the signal from the uranium radioactivity of a uranium-SCSN-38 test calorimeter was studied with the three in the ZEUS calorimeter implemented uranium-plate coatings 0.2 mm V2A, 0.4 mm V2A, and 0.2 mm V2A and 0.2 mm magnetic C10 in two field directions with fields between 0.01 and 1.4 tesla. In fields oriented parallel to the calorimeter axis uranium and particle signal behave equally except for the case, in which V2A and C10 are applied. At 0.01 tesla the particle signal varies by 1% and the uranium signal by 1.5%. Both signals remain up to 0.1 tesla on this level and increase from this magnetic field. The variation reaches at 1 tesla 4.5% for the particle and 6% for the uranium signal. In the application of V2A and C10 no variation of the particle signal is to be recognized within the errors, while the uranium signal increases monotoneously from 0 to 1.5%. In perpendicularly to the calorimeter axis oriented fields from ≅ 0.3 tesla a different development in the particle and uranium signal occurs. Up to this fields the behaviour of particle and uranium signal is identical with the behaviour in the other field direction. In the application of V2A and C10 the particle respectively the uranium signal increases from 0 at 0.01 tesla to 1% respectively 1.5% at 0.03 tesla. Thereafter the plateau up to 0.1 tesla with the subsequent increasement follows. Independently on the uranium-plate coating the increasement of the uranium signal decreases from 0.3 tesla, reaches at 0.5 tesla a maximum of 3 to 4% and decreases thereafter to 1% at 1 tesla. The particle signal increases as in the other field direction and reaches a signal variation of 7% at 1 tesla. The results are used in the regardment of the magnetic-field effects on the calibration of the ZEUS calorimeter. (orig.)