John M. Martinis

High-resolution microcalorimeter energy-dispersive spectrometer for x-ray microanalysis and particle analysis

We have developed a high-resolution microcalorimeter energy-dispersive spectrometer (EDS) at NIST that provides improved x-ray microanalysis of contaminant particles and defects important to the semiconductor industry. Using our microcalorimeter EDS mounted on a scanning electron microscope (SEM), we have analyzed a variety of specific sized particles on Si wafers, including 0.3 μm diameter W particles and 0.1 μm diameter Al2O3 particles. To compare the particle analysis capabilities of microcalorimeter EDS to that of semiconductor EDS and Auger electron spectroscopy (AES), we report measurements of the Al-Kα/Si-Kα x-ray peak intensity ratio for 0.3 μm diameter Al2O3 particles on Si as a function of electron beam energy. We also demonstrate the capability of microcalorimeter EDS for chemical shift measurements.

Deployment of the first CDMS II ZIP Detectors at the Stanford Underground Facility

Abstract The CDMS II experiment deployed the first set of ZIP (Z-dependent Ionization and Phonon) detectors at the Stanford Underground Facility (SUF) shallow depth site in the spring of 2000. With a payload consisting of 3 Ge (250g ea.) and 3 Si (100g ea.) ZIPs, the run was the first demostration of multiple ZIPs operating simltaneously. Good discrimination between electron and nuclear recoil events of 99.8% was established, down to recoil energies of 10 keV. A measurement of the γ, β, and neutron backgrounds was made.

PERFORMANCE AND BACKGROUND MEASUREMENTS OF THE CDMS II TOWER I DETECTORS AT THE STANFORD UNDERGROUND FACILITY

T. SAAB, P.L. BRINK, L. BAUDIS, B. CABRERA, J.P. CASTLE, ANDC. CHANGDepartment of Physics, Stanford University, Stanford, CA 94350, USAR. J. GAITSKELL AND J.P. THOMSONDepartment of Physics, Brown University, Providence, RI 02912, USAD.S. AKERIB, D. DRISCOLL, S. KAMAT, T.A. PERERA, R.W. SCHNEEAND G. WANGDepartment of Physics, Case Western Reserve University, Cleveland, OH44106, USAM. B. CRISLER, R. DIXON AND D. HOLMGRENFermi National Accelerator Laboratory, Batavia, IL 60510, USAJ.H. EMES, R.R. ROSS, A. SMITH AND G.W. SMITHLawrence Berkeley National Laboratory, Berkeley, CA 94720, USAJ.M. MARTINISNational Institute of Standards and Technology, Boulder, CO 80303, USAT. SHUTTDepartment of Physics, Princeton University, Princeton, NJ 08544, USAB.A. YOUNGDepartment of Physics, Santa Clara University, Santa Clara, CA 95053, USAM.S. ARMEL, V. MANDIC, P. MEUNIER, W. RAU, B. SADOULET ANDD.N. SEITZDepartment of Physics, University of California, Berkeley, Berkeley, CA 94720,

WIMP EXCLUSION RESULTS FROM THE CDMS EXPERIMENT

In early 2000 CDMS set the most competitive exclusion limit for scalar-interaction WIMPs at the Stanford Underground Facility (SUF). A new search (CDMS II) is now commencing at the Deep-site Soudan Facility.

Present results and future goals of the Cryogenic Dark Matter Search

The Cryogenic Dark Matter Search (CDMS) uses Ge and Si detectors to search for Weakly Interacting Massive Particles (WIMPs) via their elastic-scattering interaction with atomic nuclei. The present results from CDMS give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude previously unexplored parameter space above 10 GeV/c2. The second phase of the CDMS experiment, scheduled to start in January 2002, is expected to improve on the present sensitivity by more than two orders of magnitude.