A study of the spectroscopic performance of a CdTe microstrip detector

A study of the spectroscopic performance of a CdTe detector, equipped with a "strip anode" placed between two parallel focusing strips, was carried out. The focusing strips were kept at an intermediate bias voltage with respect to anode and cathode. This configuration increases the intensity and focuses the weighing field on the region surrounding the strip anode, thus improving the uniformity of signals due to the collection of electrons. The detector was irradiated with a narrow photon beam emitted by a ⁵⁷Co source. When the photon beam is impinging perpendicularly to the cathode plane, the spectroscopic response of the strip anode detector looks better than that obtained by the usual "full anode" CdTe detectors, especially with regard to the photopeak in the 122-keV energy region. Previous measurements carried out on detectors having the same crystal size, but equipped with a full anode, showed a considerable improvement in spectroscopic performance at 122 keV, when the photon beam was impinging on the detector at almost grazing angle with respect to the cathode surface . In this paper, a similar set of measurements at variable angle of the photon beam is carried out on detectors having strip anode configuration in order to investigate their behavior under the same experimental conditions.