Study of Compatibility of a Silicon Drift Detector With a MRI System

The Silicon Drift Detector (SDD) has been successfully employed as scintillation photodetector in the development of new gamma-ray detectors, with particular application in the field of medical imaging. In addition to other advantages, the SDD may offer a good insensitivity to magnetic fields, which represents an important feature for the use of this device in combination with MRI (Magnetic Resonance Imaging). In this work, we carry out a study about the behavior of a SDD when operated inside a MRI apparatus. We have evaluated the performances of a single detection unit which is the basic component for the realization of future imagers composed by arrays of several SDDs. The main effects on the charge collection in a SDD due to the presence of a constant magnetic field was simulated and experimentally tested on a prototype. Moreover, the effects of both gradient fields and radiofrequency signals on the device and related electronics were evaluated. Tests were also performed to verify that the presence of the detection system did not significantly perturb the images acquired with the MRI system. The experimental characterization was undertaken with a simplified detection system operated in simultaneous acquisition with a commercial MRI scanner operating at 7 T.