Characterization of a submillimeter high-angular-resolution camera with a monolithic silicon bolometer array for the...

Area of Science:

• Astronomy and Astrophysics
• Instrumentation
• Cryogenics

Background:

• Submillimeter astronomy requires sensitive detectors to observe faint atmospheric signals.
• The Caltech Submillimeter Observatory (CSO) provides a platform for atmospheric window observations.

Purpose of the Study:

• To construct and characterize a 24-pixel bolometer camera for the CSO.
• To assess the performance and sensitivity of the new instrument for astronomical observations.

Main Methods:

• Utilized a monolithic silicon bolometer array cooled to 300 mK with a (3)He refrigerator.
• Employed field-effect transistors for first-stage amplification at 130 K.
• Designed an optical system with mirrors and cold stops for sky imaging onto the array.

Main Results:

• Achieved detector noise of 5 × 10(-15) W/√Hz at 350 μm.
• Measured a system noise-equivalent flux density of approximately 4 Jy/√Hz.
• Demonstrated instrument sensitivity within 2.5 times the background limit.

Conclusions:

• The developed bolometer camera is a sensitive instrument for submillimeter astronomy.
• The performance metrics indicate the camera is suitable for observations in the 350- and 450-μm atmospheric windows.
• The instrument's capabilities approach the theoretical background limit for its operating wavelengths.