Predicting the response of a submillimeter bolometer to cosmic rays

Area of Science:

• Astrophysics
• Detector Physics

Background:

• Bolometers are sensitive detectors for submillimeter radiation.
• They can also be affected by high-energy particles like gamma rays, producing signal artifacts called glitches.
• Removing these glitches is essential for accurate data analysis in sensitive instruments.

Purpose of the Study:

• To investigate the response of a prototype Planck High Frequency Instrument bolometer to gamma radiation.
• To determine if the location of gamma-ray absorption affects the bolometer's response.
• To refine the thermal model for accurate glitch time constant determination.

Main Methods:

• Irradiation of a prototype bolometer with an Americium-241 gamma radiation source.
• Characterization of the bolometer's electrical and optical properties.
• Comparison of experimental results with a detailed thermal model.

Main Results:

• No significant variation in response was observed based on the location of gamma-ray absorption.
• Optically measured time constants were found to underestimate the detector recovery time from radiation events.
• A comprehensive thermal model, using parameters from electrical and optical measurements, accurately predicted recovery time constants.

Conclusions:

• The bolometer absorber and thermistor exhibit rapid thermalization.
• The developed thermal model provides accurate time constants for glitch removal.
• Slight model deviations at high energies suggest the need for an extended thermal model.