Avalanche photo diode with local negative feedback sensitive to UV, blue and green light

A new type of avalanche photo diode with negative feedback based on a Metal-Resistor-Semiconductor (MRS) structure and sensitive to UV, blue and green light was tested using a ¹³⁷Cs β-source with electrons impinging a front surface of the detector, and also with ⁹⁰Sr β-source illuminating a 1 mm diameter scintillating fiber. MRS detectors of this type are built on low resistivity n-silicon. The sensitivity of the detector is calibrated using the ionization loss of ¹³⁷Cs β-electrons. We conclude that these detectors have characteristics well suited to medical imaging applications, in particular wavelength dependence, quantum efficiency and sensitivity, and intrinsic multiplication.