Pulse mode operation of silicon diode for low temperature measurements below 20K

摘要

A Personal Computer compatible add-on-card for low temperature measurements below 10 K using a silicon diode sensor in pulse mode operation has been designed, fabricated and tested at the Materials Science Division, Indira Gandhi Center for Atomic Research, Kalpakkam. The design permits pulse mode biasing of the silicon diode and the acquisition of amplified voltage drop across the diode through a 12-bit ADC to the PC bus. The pulse mode biasing of the silicon diode prevents self-heating of the sensor especially when it is below 20 Kelvin and this enhances the sensitivity of the silicon diode sensor at very low temperatures. The amplified diode signal and the subsequent 12 bit conversion provides a high resolution measurement with good linearity and stability. The performance of this card compares excellently with steady state biasing.