In this study, TlBr detectors were irradiated with 25MeV protons accelerate
d by an AVF cyclotron. Isothermal annealing was performed to restore the pe
rformance of the detectors. In order to characterize the radiation damage a
nd thermal annealing effects on the TlBr detectors, we measured current-vol
tage (I-V) characteristics, mobility-lifetime (mu tau) products and spectro
metric responses. The I-V and mu tau measurements suggest that electron tra
ps have been induced by 25MeV protons in the TlBr crystals. X- and gamma-ra
y energy spectra were measured for two different electronic conditions: the
electric signals induced mainly by electron carriers traversing the crysta
l were used for one case and the signal induced by hole carriers were used
in the other case. After irradiation of 25MeV protons, the Am-241 X- and ga
mma-ray spectra obtained in the former showed significantly degraded energy
resolution. No degradation of energy resolution, however, was observed in
the latter case. Noticeable improvements of the degraded detector performan
ce have been observed after the thermal annealing.