Instrumentation, acquisition and analysis of the Phase II SIMPLE dark matter search signals

Abstract

I describe the new instrumentation for the SIMPLE dark matter search experiment, and its use in identifying, validating and rejecting non-WIMP backgrounds in the first stage of the Phase II project measurements. Beyond intrinsic acoustic background discrimination, evidence is provided for discrimination between {\alpha}- and neutron-induced events via analysis of the signal parameters. Analysis of the first stage result of the Phase II measurements yields 14 events associated with the ambient neutron field, consistent with MCNP simulations which include all materials radio-assays and full measurement shielding.