Study of the performance of HPGe detectors operating in very high magnetic fields

A new generation of high-resolution hypernuclear γ-spectroscopy experiments using high-purity germanium (HPGe) detectors is presently designed for the FINUDA spectrometer at DAΦNE, the Frascati Φ-factory, and for PANDA, the View the MathML source hadron spectrometer at the future FAIR facility. In both spectrometers the HPGedetectors have to be operated in strong magneticfields. In this paper we report on a series of measurements performed on a HPGedetector inserted in a magneticfield of intensity up to 2.5 T, the highest ever reached for operations with a HPGe, and with different orientations of the detector's axis with respect to field direction. A significant worsening of the energy resolution was found, but with a moderate loss of the efficiency. The most relevant features of the peak shapes, described by bi-Gaussian functions, are parametrized in terms of field intensity and energy: this allows to correct the spectra measured in magneticfield and to recover the energy resolution almost completely.