Monolithic Ge:Ga Detector Development for SAFARI

TL;DR

This paper discusses the development of a monolithic Ge:Ga detector array for the SAFARI instrument, building on existing technologies from the AKARI satellite to achieve improved performance for far-infrared observations.

Contribution

It introduces a new 64x64 Ge:Ga detector array for SAFARI, with advancements in reducing noise and optical cross-talk, based on proven fabrication techniques.

Findings

Achieved responsivity of 10 A/W in previous AKARI detectors

Developed prototype arrays demonstrating reduced read-out noise

Implemented multi-layer antireflection coatings to mitigate spectral fringes

Abstract

We describe the current status and the prospect for the development of monolithic Ge:Ga array detector for SAFARI. Our goal is to develop a 64x64 array for the 45 -- 110 um band, on the basis of existing technologies to make 3x20 monolithic arrays for the AKARI satellite. For the AKARI detector we have achieved a responsivity of 10 A/W and a read-out noise limited NEP (noise equivalent power) of 10^-17 W/rHz. We plan to develop the detector for SAFARI with technical improvements; significantly reduced read-out noise with newly developed cold read-out electronics, mitigated spectral fringes as well as optical cross-talks with a multi-layer antireflection coat. Since most of the elemental technologies to fabricate the detector are flight-proven, high technical readiness levels (TRLs) should be achieved for fabricating the detector with the above mentioned technical demonstrations. We demonstrate some of these elemental technologies showing results of measurements for test coatings and prototype arrays.