Juan I. Collar

Associate Professor

Ph.D., University of South Carolina, 1992
 
Contact Information
Phone: 773-702-4253
Location: LASR 214
Email: collarkicp.uchicago.edu
WWW: Web Site
 
Research
A prototype bubble chamber sensitive to Weakly Interacting Massive Particles (WIMPs).
My main interest is in the development of innovative methods for the detection for hypothetical astroparticles (WIMPs, axions, magnetic monopoles, any yet-to-be-discovered component of cosmic rays that might constitute a fraction of the 'dark matter'). Needless to say, this is a risky business, but I am equally interested in the journey and the destination: the extreme levels of sensitivity required in some of these experiments force us to devise new detection technologies, in an endless quest for the 'better mouse-trap'. It is a very enjoyable challenge. I am also attracted to other exotica such as double-beta decay and some 'hard' problems in neutrino detection (coherent neutrino scattering, detection of the relic neutrino sea). I enjoy the condensed-matter aspects of detector development and anything having to do with the interactions between radiation and matter. I get easily excited about cross-disciplinary endeavors and real-life applications of detectors that might otherwise be chasing ghost particles.

Together with collaborators at the Groupe de Physique des Solides (Universite Paris VII), University of Lisbon, and Pacific Northwest National Laboratory, I developed large-mass, low-background superheated droplet detectors (SDDs) dedicated to WIMP (Weakly Interacting Massive Particle) searches (The SIMPLE dark matter search). On my arrival to Chicago I started investigating the possibility of making large bubble chambers stable enough for the same goal, using CF3I, a target ideal for WIMP detection. Our collaboration with FNAL and Indiana University (The Chicago Observatory for Underground Particle Physics, COUPP) has already led to the best sensitivity to spin-dependent WIMP interactions. We presently work on a 60 kg and 500 kg CF3I chamber. We expect the first, to be installed in SNOlab during 2010, to provide a similar leading sensitivity also to spin-independent WIMP couplings. At CERN I am involved in CAST, a search for solar axions using a decommissioned LHC test magnet, an interesting astroparticle spin-off from the Large Hadron Collider effort. More recently, I have worked on the application of P-type Point Contact germanium detectors to coherent neutrino-nucleus scattering, double beta decay and searches for light dark matter candidates. These devices have already produced some very interesting results within the CoGeNT and MAJORANA experiments.

Ongoing Scientific Projects:
 
KICP Highlights & News

 
Talks, Lectures, & Workshops

 
Students
Past Students

GRADUATE: Drew Fustin (2012), Matthew Szydagis (2010), Phil Barbeau (2009), Nathan Riley (2008), Dante Nakazawa (2006)

UNDERGRADUATE: Alan Salkanovic (2013), Eli Byers Barrows (2012), Natalie Harrison (2012), Songkiat Nutalaya (2012), Steven Bogacz (2012), Muneeb Hai (2010), Hannes Schimmelpfennig (2009), Jacob Claussen (2008), Adrian Culver (2008), Luke Goetzke (2008), Charles Greenberg (2008), Keith Crum (2007), Smriti Mishra (2007), Julia Rasmussen (2006), Kevin O'Sullivan (2005), Aza Raskin (2005), Taylor Aune (2004)
 
KICP Publications
2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 | 2002 | 2001


Latest Journal Publications
  1. "Comment on "Fitting the annual modulation in DAMA with neutrons from muons and neutrinos''", arXiv:1409.3185 (Sep 2014)
  2. "Comments on "A Dark Matter Search with MALBEK"", arXiv:1407.2581 (Jul 2014)
  3. "Coherent neutrino-nucleus scattering detection with a CsI[Na] scintillator at the SNS spallation source", arXiv:1407.7524 (Jul 2014)
  4. "Search for Solar Axions by the CERN Axion Solar Telescope with He3 Buffer Gas: Closing the Hot Dark Matter Gap", Physical Review Letters, Volume 112, Issue 9, id.091302 (Mar 2014)
  5. "Search for An Annual Modulation in Three Years of CoGeNT Dark Matter Detector Data", arXiv:1401.3295 (Jan 2014)
  6. "Quenching and channeling of nuclear recoils in NaI(Tl): Implications for dark-matter searches", Physical Review C, vol. 88, Issue 3, id. 035806 (Sep 2013)
  7. "CoGeNT: A search for low-mass dark matter using p-type point contact germanium detectors", Physical Review D, vol. 88, Issue 1, id. 012002 (Jul 2013)
  8. "Direct measurement of the bubble-nucleation energy threshold in a CF3I bubble chamber", Physical Review D, vol. 88, Issue 2, id. 021101 (Jul 2013)
  9. "The C-4 dark matter experiment", Nuclear Instruments and Methods in Physics Research A, Volume 712, p. 27-33 (Jun 2013)
  10. "CAST constraints on the axion-electron coupling", Journal of Cosmology and Astroparticle Physics, Issue 05, article id. 010, pp. (2013) (May 2013)
  11. "Applications of an Y88/Be Photoneutron Calibration Source to Dark Matter and Neutrino Experiments", Physical Review Letters, vol. 110, Issue 21, id. 211101 (May 2013)
  12. "Characteristics of signals originating near the lithium-diffused N+ contact of high purity germanium p-type point contact detectors", Nuclear Instruments and Methods in Physics Research A, Volume 701, p. 176-185 (Feb 2013)
  13. "First dark matter search results from a 4-kg CF3I bubble chamber operated in a deep underground site", Physical Review D, vol. 86, Issue 5, id. 052001 (Sep 2012)
  14. "Results and perspectives of the solar axion search with the CAST experiment", arXiv:1209.6347 (Sep 2012)
  15. "A Maximum Likelihood Analysis of Low-Energy CDMS Data", arXiv:1204.3559 (Apr 2012)
  16. "Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with He3 Buffer Gas", Physical Review Letters, vol. 107, Issue 26, id. 261302 (Dec 2011)
  17. "Astroparticle physics with a customized low-background broad energy Germanium detector", Nuclear Instruments and Methods in Physics Research A, Volume 652, Issue 1, p. 692-695 (Oct 2011)
  18. "Astroparticle physics with a customized low-background broad energy Germanium detector", Nuclear Instruments and Methods in Physics Research A, Volume 652, Issue 1, p. 692-695 (Oct 2011)
  19. "Search for an Annual Modulation in a p-Type Point Contact Germanium Dark Matter Detector", Physical Review Letters, vol. 107, Issue 14, id. 141301 (Sep 2011)
  20. "Results from a Search for Light-Mass Dark Matter with a p-Type Point Contact Germanium Detector", Physical Review Letters, vol. 106, Issue 13, id. 131301 (Apr 2011)

Latest Conference Proceedings
  1. "A measurement of the K-shell decays in the CoGeNT public dataset", American Physical Society, APS April Meeting 2013, April 13-16, 2013, abstract #E2.021 (Apr 2013)
  2. "The MAJORANA experiment: an ultra-low background search for neutrinoless double-beta decay", Journal of Physics: Conference Series, Volume 381, Issue 1, article id. 012044, 6 pp. (2012) (Sep 2012)
  3. "The Majorana Demonstrator: A Search for Neutrinoless Double-beta Decay of Germanium-76", Journal of Physics: Conference Series, Volume 375, Issue 4, id. 042010 (2012) (Jul 2012)
  4. "Dark matter sensitivities of the Majorana Demonstrator", Journal of Physics: Conference Series, Volume 375, Issue 1, id. 012014 (2012) (Jul 2012)
  5. "Status and perspectives of the CAST experiment", Journal of Physics: Conference Series, Volume 375, Issue 2, id. 022001 (2012) (Jul 2012)
  6. "The Majorana Demonstrator: A search for neutrinoless double-beta decay of germanium-76", 19TH PARTICLES AND NUCLEI INTERNATIONAL CONFERENCE (PANIC11). AIP Conference Proceedings, Volume 1441, pp. 480-482 (2012) (Apr 2012)
  7. "Dark Matter Detection with Bubble Chambers", Nuclear Physics B Proceedings Supplements, Volume 221, p. 379-379 (Dec 2011)
  8. "C4: Prospects for an expanded search for light-mass WIMPS", American Physical Society, 2011 Fall Meeting of the APS Division of Nuclear Physics, October 26-29, 2011, abstract #JG.005 (Oct 2011)
  9. "The MAJORANA Experiment", Nuclear Physics B Proceedings Supplements, Volume 217, Issue 1, p. 44-46 (Aug 2011)
  10. "Latest results and prospects of the CERN Axion Solar Telescope", Journal of Physics: Conference Series, Volume 309, Issue 1, id. 012001 (2011) (Aug 2011)

 
Visitors
Past Visitors:
  1. Miguel Ardid, Universitat Politecnica de Valencia (2014)
  2. Dipak Rimal, University of Florida (2014)
  3. Manuel Bou, Polytechnic University of Valencia (2012)
  4. Alvaro Chavarria, Princeton University (2012)
  5. Rafael Lang, Purdue University (2012)
  6. María Luisa Sarsa, University of Zaragoza (2012)
  7. Miguel Ardid, Universitat Politècnica de València (2011)
  8. Manuel Bou, UPV - IGIC (2011)
  9. Todd Hossbach, Pacific Northwest National Laboratory (2011)
  10. Paolo Gondolo, University of Utah (2010)
  11. Sam Waldman, Massachusetts Institute of Technology (2010)
  12. Juan Gomez-Cadenas, IFIC (CSIC-UV) SPAIN (2009)
  13. Carl Dahl, Princeton University (2008)
  14. Richard Gaitskell, Brown University (2007)
  15. Andrea Pocar, Stanford University (2007)
  16. William Wester, Fermi National Accelerator Laboratory (2007)
  17. Silvia Borghi, CERN (2006)
  18. Dan Akerib, Case Western Reserve University (2004)
  19. Frank Avignone, University of South Carolina (2003)
  20. Robynne Hooper, University of Texas, Austin (2003)
  21. Peter Gorham, University of Hawaii (2002)
  22. Harry Miley, Pacific Northwest National Laboratory (2002)
  23. Andre Sonnenschein, Princeton University (2002)