Study of the effect of external noise pickups on the performance of a cryogenic bolometer

TL;DR

This study investigates how external noise sources affect the performance of a cryogenic bolometer, identifying key noise contributors and demonstrating their impact on detector resolution at very low temperatures.

Contribution

It provides a detailed noise characterization and mitigation strategies for cryogenic bolometers, highlighting the influence of external noise on detector resolution.

Findings

External noise from ground loops and electronics degrades bolometer resolution.

Best resolution achieved is ~15 keV at 15mK, limited mainly by pulse tube cryocooler noise.

Systematic comparison of noise sources informs mitigation approaches.

Abstract

This paper reports the detailed noise characterization, investigation of various noise sources and its mitigation to improve the performance of a cryogenic bolometer detector. The noise spectrum has been measured for a sapphire bolometer test setup with indigenously developed NTD Ge sensor in the CFDR system at Mumbai. The effect of external noise, arising either from ground loops in the system or from the diagnostic and control electronics of the cryostat, on the performance of a cryogenic bolometer is assessed. A systematic comparison of the influence of different noise pickups on the bolometer resolution is also presented. The best-achieved resolution at 15mK is ~15 keV for heater pulses and appears to be mainly limited by the noise due to the pulse tube cryocooler.