SuperCDMS Development Project: Detectors: Superconducting Electronics Systems R&D

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The CDMS (Cryogenic Dark Matter Search) II experiment at the Soudan Underground Mine in Minnesota currently leads the field in the search for direct detection of the dark matter particles that apparently constitute a quarter of the mass of the universe. Motivated by the great interest and excitement over the recent improved WIMP (Weakly Interacting Massive Particle) search limits from CDMS-II, the collaboration is considering ways to explore substantially greater regions of possible WIMP cross sections. It is clear that there is substantial scientific interest in mounting experiments with an eventual sensitivity reach more than a factor of a thousand beyond the current limits, a level that would test much of the theoretically allowed parameter space. Some of this will be achieved with continued running of CDMS-II, but that will become background limited before it can reach the desired level. However, the CDMS-II technology is capable of reaching this level of sensitivity with a substantial increase in mass, reduction in background events, and relocation to a deeper underground site.With continued development efforts in detector fabrication and testing, and a coordinated program aimed at background identification and reduction, an experiment with 25 kg of detector mass could be operational by 2008. The cryogenics system of this experiment would be planned to allow further expansion, so that additional improvements in mass production and testing of detectors could yield a phased increase in detector mass up to 1000 kg.The CDMS-II collaboration proposes to continue running that apparatus to the end of 2006 to obtain the best limit achievable with that apparatus. Concurrently, a detector R&D project will proceed to develop SuperCDMS, the 25 kg detector, to be housed in the Sudbury Neutrino Observatory Laboratory in Canada. This individual proposal from the University of Colorado at Denver and Health Sciences Center represents a request for support of the PI's long-term development of cryogenic electronics systems for improved detector technology and increased sensitivity. There are three aspects to the long-term work: 2-stage superconducting quantum interference device (SQUID) pre-amplifier development, SQUID charge-readout development, and dissemination of SQUID operational expertise to collaborating groups.The intellectual merit of this proposed long-term activity is a) development of improved dark-matter detectors and systems, b) increased collaboration between cooperating NSF institutions, and c) broad support of an enabling technology (SQUIDs) which is important to a number of additional scientific programs, including novel SQUID devices and electronics development.The broader impacts resulting from the proposed activity include a) undergraduate education in a non-traditional student population and b) interactions between those students and graduate students and post-docs at from other institutions, encouraging consideration of graduate education by these students science and engineering fields in which they are generally under-represented.