Indigenous Development of a Millikelvin Refrigerator at VECC, Kolkata

Abstract

area compared to that of the more conventional triangularly serrated TE wing with identical zero-serration TE lines.TE serrations formed by primary remiges in a barn owl wing which typically contributes to noise suppression, were appended to a planar metallic delta wing, and used to reduce edge return contributions to the backscatter due to the interaction of surface traveling waves with the wing TE in an electromagnetic field. Results indicate the efficacy of barn owl type TE serration in reducing the RCS of the host delta wing especially in the crucial noseon incidence. These serrations also become effective away from nose-on incidences with an increase in electrical size arising from decrease in the incident wavelength of incident harmonic wave. The present study indicates more optimized TE serrations inspired by that evolved for bird of prey like the barn owl for silent flight, may be able to RCS of aircraft wing in an EM field, while maintaining higher wing area for superior aerodynamic performance of the host configuration compared to more conventional serrations. Technologies related to production of millikelvin temperature have been developed and tested in the laboratory. All the critical components were assembled to make a complete dilution refrigerator. The refrigerator was successfully run and commissioned in VECC. The system involves several advanced cryogenic concepts especially the capillary impedance and heat exchanger. A temperature to the tune of 50 mK has been achieved. This is the first development of its kind in India, and likely to usher a new wave in the research arena of advanced cryogenics.