About the SuperCDMS Experiment
In recent years there has been compelling evidence, from a number of astronomical observations, for the existence of a type of matter that is different from that which makes up the visible portion of the universe such as stars, planets, web-servers, and scientists. This type of matter has yet to be directly observed in earth-bound experiments nor created at particle colliders. Since the evidence for its existence is based on its gravitational effects on the rest of matter in the universe, it is often referred to as the "Missing Mass" of the universe.
The "Missing Mass" is matter that does not emit or scatter electromagnetic radiation and therefore it cannot be seen, which has earned it the title Dark Matter. Dark matter constitutes approximately a quarter of all matter and energy in the universe; while the everyday matter (such as all the particles, atoms, molecules, ... all the way up to planets and stars) is only ~4%. The rest (approximately three quarters) of all the matter and energy in the universe is referred to as dark energy. Dark matter is most commonly hypothesized to be made up of exotic particles such as WIMPS (Weakly Interacting Massive Particles). The goal of the SuperCDMS experiment is to detect the WIMPs and study their properties in order to resolve the "Missing Matter" puzzle and achieve a better understanding on the major matter consituent of the universe.
The SuperCDMS experiment aims to measure the recoil energy imparted to a nucleus due to collisions with WIMPs by employing detectors which are higly sensitive to the ionization and phonon signals that results from a WIMP-nucleus collision. The detectors, known as iZIP (interleaved Z-sensitive Ionization Phonon) detectors, feature state-of-the-art superconducting thin films deposited on 600g germanium crystals to accurately measure information about the WIMP collisions. The SuperCDMS experiment will initially be at the Soudan Underground Laboratory in Minnesota where in it will operate a total detector mass of ~10kg. Subsequently, the experiments plans to increase the experimental payload by a factor of 10 and operate at the deeper SNOLAB facility in Sudbury, Canada. This location provides significantly improved shielding from cosmic rays which are a source of background in the WIMP search.
Download the research brochure about our activities at the Soudan facility. Click here for more information!
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In recent years there has been compelling evidence, from a number of astronomical observations, for the existence of a type of matter that is different from that which makes up the visible portion of the universe such as stars, planets, web-servers, and scientists. This type of matter has yet to be directly observed in earth-bound experiments nor created at particle colliders. Since the evidence for its existence is based on its gravitational effects on the rest of matter in the universe, it is often referred to as the "Missing Mass" of the universe.
The "Missing Mass" is matter that does not emit or scatter electromagnetic radiation and therefore it cannot be seen, which has earned it the title Dark Matter. Dark matter constitutes approximately a quarter of all matter and energy in the universe; while the everyday matter (such as all the particles, atoms, molecules, ... all the way up to planets and stars) is only ~4%. The rest (approximately three quarters) of all the matter and energy in the universe is referred to as dark energy. Dark matter is most commonly hypothesized to be made up of exotic particles such as WIMPS (Weakly Interacting Massive Particles). The goal of the SuperCDMS experiment is to detect the WIMPs and study their properties in order to resolve the "Missing Matter" puzzle and achieve a better understanding on the major matter consituent of the universe.
The SuperCDMS experiment aims to measure the recoil energy imparted to a nucleus due to collisions with WIMPs by employing detectors which are higly sensitive to the ionization and phonon signals that results from a WIMP-nucleus collision. The detectors, known as iZIP (interleaved Z-sensitive Ionization Phonon) detectors, feature state-of-the-art superconducting thin films deposited on 600g germanium crystals to accurately measure information about the WIMP collisions. The SuperCDMS experiment will initially be at the Soudan Underground Laboratory in Minnesota where in it will operate a total detector mass of ~10kg. Subsequently, the experiments plans to increase the experimental payload by a factor of 10 and operate at the deeper SNOLAB facility in Sudbury, Canada. This location provides significantly improved shielding from cosmic rays which are a source of background in the WIMP search.
Download the research brochure about our activities at the Soudan facility. Click here for more information!
Latest News
Scaling up the search for dark matter
Karl van Bibber; Published January 5, 2009: New upper limits on the spin-independent interaction of WIMPs and nucleons marks the latest volley in the worldwide effort to detect and identify particle dark matter.The dynamical evidence for dark matter in the universeanomalously large velocities of stars within galaxies, and galaxies within clustersgoes back three-quarters of a century [1]. Within the past decade, precision measurements of cosmological parameters have pinned down the partitioning of the energy density of the universe rather neatly: dark energy accounts for roughly three-fourths, and matter of all forms makes up only a quarter. Of the latter, nonbaryonic dark matter accounts for about five parts in six [2]. What this elusive invisible matter actually is represents one of the pre-eminent questions in all of science. In Physical Review Letters, Ahmed et al. [3] report results from one of the collaborations involved in the hunt for dark matter that place new upper bounds on the extent of any possible interaction between certain kinds of dark-matter particles and normal matter.
One or more species of particle relics from the big bang are increasingly favored as the elusive dark-matter, with well-motivated beyond-Standard-Model candidates such as axions [4] and weakly interacting massive particles (WIMPs) [5] at the top of a short listalthough one must be open to surprise. At present the neutralino, or WIMP, from the so-called supersymmetric theories enjoys wide currency as the favorite contender. These theories have the attractive feature of both preventing particle masses from being much heavier than they are, as well as unifying three of the four forces of nature. Such particles are expected to be in the range of 10 to 1000 times the proton mass, and should interact with cross sections characteristic of the weak interaction scale.... Click here to continue reading at APS Physics
Click here for more news!
One or more species of particle relics from the big bang are increasingly favored as the elusive dark-matter, with well-motivated beyond-Standard-Model candidates such as axions [4] and weakly interacting massive particles (WIMPs) [5] at the top of a short listalthough one must be open to surprise. At present the neutralino, or WIMP, from the so-called supersymmetric theories enjoys wide currency as the favorite contender. These theories have the attractive feature of both preventing particle masses from being much heavier than they are, as well as unifying three of the four forces of nature. Such particles are expected to be in the range of 10 to 1000 times the proton mass, and should interact with cross sections characteristic of the weak interaction scale.... Click here to continue reading at APS Physics
Latest Publications
Low-threshold analysis of CDMS shallow-site data, published in Phys. Rev. D82, 122004 (2010)
Announcement talks December 12, 2009
Click here for the slides used in the Jodi Cooley presentation(pdf)
High resolution .mov copies of the Jodi Cooley presentation:
(822 MB Quicktime)
(403 MB MPEG-4)
Other talks:
Lauren Hsu Fermilab (pdf) & Video of the Lauren Hsu presentation
Talk of B. Sadoulet at the APC (Paris) 11 February 2010 (pdf)
Talk of J. Hall at the Marina del Rey Dark Matter workshop 26 February 2010 (pdf)
Talk of P. Brink at the Marina del Rey Dark Matter workshop 26 February 2010 (pdf)
Click here for more publications!
Low-threshold results
Results from a Low-Energy Analysis of the CDMS II Germanium Data, Phys. Rev. Lett. 106 131302 (2011)We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs) with masses below ~10 GeV/c^2. This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c^2 and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.
Papers: arXiv:1011.2482 and PRL paper
Low-threshold analysis of CDMS shallow-site data, published in Phys. Rev. D82, 122004 (2010)
Data taken during the final shallow-site run of the first tower of the Cryogenic Dark Matter Search (CDMS II) detectors have been reanalyzed with improved sensitivity to small energy depositions. Four ~224 g germanium and two ~105 g silicon detectors were operated at the Stanford Underground Facility (SUF) between December 2001 and June 2002, yielding 118 live days of raw exposure. Three of the germanium and both silicon detectors were analyzed with a new low-threshold technique, making it possible to lower the germanium and silicon analysis thresholds down to the actual trigger thresholds of ~1 keV and ~2 keV, respectively. Limits on the spin-independent cross section for weakly interacting massive particles (WIMPs) to elastically scatter from nuclei based on these data exclude interesting parameter space for WIMPs with masses below 9 GeV/c^2. Under standard halo assumptions, these data partially exclude parameter space favored by interpretations of the DAMA/LIBRA and CoGeNT experiments' data as WIMP signals, and exclude new parameter space for WIMP masses between 3 GeV/c^2 and 4 GeV/c^2.
Papers: arXiv:1010.4290v3 and PRD paper
Latest results of CDMS-II, December 17, 2009
Summary of the results (pdf) Science article 2/12/2010Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models. (Abstract)
Click for: Printed report (pdf) and Supplementary Online Material (pdf)
Announcement talks December 12, 2009
Click here for the slides used in the Jodi Cooley presentation(pdf)
High resolution .mov copies of the Jodi Cooley presentation:
(822 MB Quicktime)
(403 MB MPEG-4)
Other talks:
Lauren Hsu Fermilab (pdf) & Video of the Lauren Hsu presentation
Talk of B. Sadoulet at the APC (Paris) 11 February 2010 (pdf)
Talk of J. Hall at the Marina del Rey Dark Matter workshop 26 February 2010 (pdf)
Talk of P. Brink at the Marina del Rey Dark Matter workshop 26 February 2010 (pdf)
This work is supported by the National Science Foundation and the Department of Energy