Large-format photodetecting system pCam6060 with a GSENSE6060BSI CMOS detector, developed at SAO RAS and optimized for photometric methods

TL;DR

The paper presents the development and optimization of the pCam6060, a large-format CMOS-based photodetecting system optimized for astronomical photometric methods, featuring high sensitivity, wide spectral range, and low noise performance.

Contribution

It introduces a novel large-format CMOS photodetector system with extended dynamic range and optimized for faint object detection in astronomy.

Findings

High quantum efficiency across 200-1040 nm range

Low readout noise of about 3 electrons

Dynamic range of about 100,000 electrons

Abstract

The pCam6060 photodetecting system was developed at SAO RAS and is based on the GSENSE6060BSI photodetector manufactured by GPixel (China) with a frame format of 6144x6144 active pixels and a pixel size of 10 mkm. The readout speed reached 11 fps. The back-illuminated detector has a wide spectral range of 200-1040 nm with a minimum quantum efficiency (QE) of 10% and maximum sensitivity of 95% at 580 nm. The quantum efficiency in the near-infrared range was 58% at 850 nm. The pCam6060 system controller implements a mode of simultaneous image readout via two 12-bit video channels with different gain and their subsequent combination in the controller into a single frame with an extended 16-bit dynamic range. This method simultaneously achieves a low readout noise level (about 3 e-) in the high-gain channel and a large dynamic range (full well capacity of about 100000 e-) in the low-gain channel. Back-illuminated CMOS detectors, unlike front-illuminated devices, do not have the effect of long-term preserving the residual charge from previous exposures, which makes them suitable for recording faint objects in photometric long-exposure observation methods. Communication between the host computer and the camera was carried out via a fiber optic line at distances of up to 50 m. Video data are recorded on the computer hard drive in real-time. The pCam6060 photodetecting system is designed for astronomical applications and has a moisture-proof design.