The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 meters) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5 to 20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.

The superAuid response of helium Alms with transition temperatures ranging from 70 mK to 0.5 K has been studied using a torsional oscillator technique. A detailed analysis of the background indicates that the initial nonsuperAuid layer has an unexpected temperature-dependent period shift and dissipation. The superfluid response obeys a general scaling law which can be derived from the Kosterlitz-Thouless theory. Comparisons with the dynamic theory reveal nonuniversal behavior as a function of coverage.

Quantitative measurements have been made of the superfluid mass per unit area for the interfacial superfluid phase present at the boundary wall of low-concentration mixtures of 4 He in liquid 3 He. We find a rapid jump in the superfluid mass at the transition temperature in agreement with the prediction of the Kosterlitz-Thouless theory of the superfluid transition in a two-dimensional system, PACS 67.60.Fp Since the successful application of the Kosterlitz-Thouless 1,2 (KT) theory of vortex pair unbinding to the understanding of the superfluid transition in thin 4 He films, a wide search has been made for other systems in which these ideas might be applicable. Extension of the theoretical ideas by Halperin and Nelson 3 and Young 4 to the case of twodimensional (2D) melting has very much increased the variety of possible systems in which one might look for a realization of a vortex (dislocation) pair unbinding transition. In this Letter we report the study of a 2D superfluid system of a type quite different in structure from the usual adsorbed film of 4 He. In the present work, we have studied the properties of a ''superfluid sandwich" formed at the container boundaries in a dilute 4 He-3 He mixture.It has been known since the early 1960's that at sufficiently low temperatures dilute mixtures of 4 He in liquid 3 He display an interesting state of "surface superfluidity." Since its discovery by Brewer and Keyston, 5 this phenomenon has been investigated extensively by Laheurte and co-workers 6-8 and more recently by Ellis et al 9 From such investigations it is clear that 4 He atoms are preferentially adsorbed on the walls of the container as a result of the relatively smaller molar volume of 4 He as compared to that of 3 He and the strong van der Waals force induced by the wall. For dilute concentrations of 4 He in bulk 3 He, the 4 He atoms are almost exclusively confined at low temperatures to the interfacial region at the boundaries of the system. The surface superfluid phase which occurs at the interfacial region of enhanced 4 He concentration is a natural candidate for 2D phase transition studies. We present here the first quantitative measurements of the superfluid properties of this system over a broad range of temperatures and concentrations.For experimental convenience, we have chosen to work with thick films of 3 He with a low concentration of 4 He. At high temperatures a certain amount of the 4 He is dissolved in the 3 He overlayer somewhat depleting the 4 He-rich layer near the wall. It is desirable to work with a 3 He layer sufficiently thick so as to have essentially bulk properties and yet sufficiently small in total volume so that the superlfuid transition is not dominated by solution effects.Torsional oscillator techniques similar to those employed by Bishop and Reppy 10 and Agnolet, Teitel, and Reppy 11 in studies of the Kosterlitz-Thouless transition in pure 4 He films are used to measure the superfluid response. The helium film is adsorbed on a Mylar substrate which constitutes the moment of...

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