Mexico-UK Sub-millimeter Camera for Astronomy

Abstract

MUSCAT is a large format mm-wave camera scheduled for installation on the Large Millimeter Telescope Alfonso Serrano (LMT) in 2018. The MUSCAT focal plane is based on an array of horn coupled lumped-element kinetic inductance detectors optimised for coupling to the 1.1mm atmospheric window. The detectors are fed with fully baffled reflective optics to minimize stray-light contamination. This combination will enable background-limited performance at  = 1.1 mm across the full 4 arcminute fieldof-view of the LMT. The easily accessible focal plane will be cooled to 100 mK with a new closed cycle miniature dilution refrigerator that permits fully continuous operation. The MUSCAT instrument will demonstrate the science capabilities of the LMT through two relatively short science programmes to provide high resolution follow-up surveys of Galactic and extra-galactic sources previously observed with the Herschel space observatory, after the initial observing campaigns. In this paper, we will provide an overview of the overall instrument design as well as an update on progress and scheduled installation on the LMT.

Pre-deployment verification and predicted mapping speed of MUSCAT

“…From this calculated mapping sensitivity, we find a simulated mapping speed of 0.63 deg 2 /mJy 2 /h for the scan rate of 400 s −1 . This simulated mapping speed is comparable to the theoretically calculated mapping speed of 3.0 deg 2 /mJy 2 /h reported by Castillo-Dominguez et al 17 using a purely bolometric model scaled by the factor ∼ 7 found by comparing the bolometric mapping speed of the AzTEC camera to the observed performance on sky at the James Clark Maxwell (JCMT) telescope. 18 Scaling Castillo-Dominguez et al's mapping speed by this factor gives a mapping speed of 0.42 deg 2 /mJy 2 /h.…”

The design and characterization of a 300 channel, optimized full-band millimeter filterbank for science with SuperSpec

“…The SuperSpec coupling optics consist of the warm mirrors under development for MUSCAT, 13 along with a subsequent set of 5 warm mirrors, and a single cold lens ( fig. 9).…”

A Continuous 100-mK Helium-Light Cooling System for MUSCAT on the LMT

“…The MUSCAT cooling chain is illustrated in Figure 1a. The full mechanical design of the MUSCAT cryostat is described by Castillo-Dominguez et al 1 but is outlined in Figure 1b. The third and fourth temperature stages of MUSCAT (the first two not cooled by the pulse tube cooler) are cooled by continuous sorption (CS) coolers.…”

“…To verify the plausibility of the cooling chain presented here, we have modelled the expected thermal load on each stage of MUSCAT, the results of this are presented in Table 1. A complete description of the structure and interfaces between stages is given by Castillo-Dominguez et al 1 The total required volume of He 3 in MUSCAT is approximately 9 L STP of gas. This consists of 4 litres in the 450-mK cooler pumps, 1.5 litres in each of the continuous soprtion ballast tanks, and 2 litres in the miniature dilutor.…”