Significant advances in the developmcmt of HEMT technology have resulted in high performance cryogenic, 1.,NAs whose noise temperatures arc within an order of magnitude of the quantum noise limit (hv/k). Key to the identification of optimum HEMT structures at cryogenic {temperatures is the clevelopmcnt of on-wafer noise and device parameter extraction techniques.

We have applied laser calorimetry to the measurement of optical absorption in monocrystalline sapphire at cryogenic temperatures. Sapphire is a promising candidate for the mirror substrates of the Large-scale Cryogenic Gravitational wave Telescope. The optical absorption coefficients of different sapphire samples at a wavelength of 1.064 μm at 5K were found to average 90 ppm/cm.

Differential frost heave, alongwith the associated cryogenic disturbance that accompanies it, is an almost universal feature of arctic landscapes that potentially influences the fate of the soil carbon (C) stored in arctic soils. In this study, we quantify how gross ecosystem photosynthesis (GEP), soil respiration (Re) and the resulting net ecosystem exchange (NEE) vary in a patterned ground sy...

The cryogenic system for the KSTAR superconducting magnets has been commissioned. It consists of a cold box, distribution boxes (DB) and cryogenic transfer lines. The cold box and DB #1 provide 600 g/s of supercritical helium to cool the superconducting (SC) magnets, their SC bus-lines, and the magnet support structures. It also provides 17.5 g/s of liquid helium to the current leads and suppli...

Since ALMA instrument will have low noise receivers with very large instantaneous bandwidth, gain stability should be carefully specified to avoid limiting the sensitivity of the total system. This memorandum reviews the methods for the characterization of gain stability in the time and frequency domain and presents examples of experimental setups used for its measurement in the case of cryogen...

Microelectronic packaging plays an important role in cryogenic engineering; in particular, a solder joint as interconnection, which offers a mechanical, thermal and electrical support, undergoes much larger and harsher thermal changes during its service compared with conventional customer electronic products. The impact of thermo-mechanical properties of such solder joints under cryogenic servi...

This document, originating within the national laboratories and their industrial collaborators, presents a series of suggestions for research and development pertaining to cryogenics. Appendix A is a tabulation of the steering committee members who participated in the development of this document. The editors have primarily used the materials and discussions provided by the steering committee a...

We prove the following results : (a) The Cube-Connected Cycles network of dimension n is a subgraph of the Butterry network of dimension n. (b) The Shuue-Exchange network of dimension n is a subgraph of the DeBruijn network of dimension n.

The Cryogenic Dark Matter Search (CDMS) and SuperCDMS experiments seek hypothetical weakly-interacting, massive particles (WIMPs) that could account for the majority of matter in the Universe, by means of cryogenic germanium detectors. We provide an update on the status of the SuperCDMS experiment, and discuss the joint CDMS-EDELWEISS analysis.