Novel p-JFET embedded in silicon radiation detectors that avoids preamplifier feedback resistor

The paper describes the design and the performance of an original p-channel JFET embedded in the collecting anode of a silicon radiation detector. The choice of a p-channel transistor, whose gate-to-channel junction is forward biased by the leakage current from the detector, avoids the preamplifier feedback resistor and performs a continuous dc reset of the collected charge. The reported design, fully compatible with the detector fabrication, makes the operation of the detector extremely simple, ensures the best charge collection capability and leads to improved charge resolution. The first detector produced with this type of transistor has a resolution of 27 electrons rms in the measurement of the collected charge at room temperature for a pixel active area of about 0.1 mm2, and of 22 electrons rms at T = 210 K