Helium Technology and Low Temperature Section

Helium plays an important role in the strategic areas of technological development and scientific research. Conventional source of helium, unlike other terrestrial gases, is the natural gas deposits. Availability of this element confined to certain geological terrains over the globe. With a mission to explore helium we have developed a cost effective and energy efficient method for extraction of it through non-cryogenic approach. The process exploits the differing adsorption affinities of various gases on to the special type of adsorbents. Li-LSX (lithium impregnated Zeolites) and activated carbon were found to be a superior candidates for helium purification by means of eliminating other undesirable gases (CH4, N2, O2 ..). The system stands out to be unique in the sense that it can handle large amount of impurities (~99.0 mol%) while yielding high degree of purity for product helium (>99.95mol%). This type of plant is particularly relevant for field installation and laboratory set up where provision for liquid cryogen, manpower and electrical power become key constraints.

In view of the technological development projects at VECC coupled with multifarious researches involving cryogenics, condensed matter and nuclear physics, we are developing a sub-Kelvin facility at VECC. Process simulation and engineering design have been firmed up. The very first stage of the system, namely the pre-cooling of the isotopic mixture of helium gas, has been successfully accomplished. Subsequent stages, heat exchangers, He-3 distillation chamber and mixing container are in the process of fabrication. We wish to achieve 10µW@100mK in the very near future. As an extension of the scope of ongoing work we aim to building a PT based dry system to facilitate a range of material science experiments of practical importance. Moreover, a RT magnet, initially around 7T, will be built up in the laboratory to couple with the dry system so as to enhance the extent of experiments.

Aside from these, significant contribution have been made to the realm of earthquake prediction research. Intended for detection of pre-monitoring geochemical signal emanating from the earth's bowels we have set up several self sustained field laboratories across the countries. We have established that precursory geochemical emission in terms of helium and radon bear the signature of a major impending tremor. Nonlinear statistical analysis corroborates the experimental observation of early emission of helium or radon prior to the occurrence of a quake within the sphere of influence.

Staff

N. KUMAR DAS	P. KUMAR MONDAL	SIDDHESWAR CHAKRABORTY	S. CHANDRA MONDAL	PRADEEP KUMAR