EDUCATION:

"Laurea” 1977, University of Naples, Italy
Ph.D. 1983, University of Geneva, Switzerland

RESEARCH:

My current research interest is the experimental study of dark matter.The leading candidates for dark matter are relic particles from the Big Bang known as Weakly Interacting Massive Particles (WIMPs). Such particles are also predicted by extensions of the standard model of particle physics, such as Supersymmetry (SUSY). If WIMPs exist, though they only very rarely interact with conventional matter, they should nonetheless be detectable as they scatter from nuclei in sufficiently sensitive detectors on Earth.The interaction rate, predicted by SUSY models, range from the current best limit of ~0.1 event/kg/day to less than 1 event/ton/ year, demanding increase in detector mass and exposure, coupled to a reduction in and improved rejection of radioactive and cosmogenic backgrounds.

Cryogenic noble liquids, such as Xenon and Argon, whose properties I have been studying for years, offer the best prospects for dark matter detectors with large mass and excellent background rejection capabilities. I am spokesperson of the XENON Experiment, designed to observe WIMPs-nucleon scattering in a ton of ultra pure liquid xenon (LXe), with unprecedented sensitivity. Using 3-D position sensitive time projection chambers (TPCs), operated in dual phase (liquid/gas), XENON aims at observing WIMPs induced nuclear recoils with energy as low as 10 keV and with a very high rejection (>99%) of the dominant background induced electron recoils.The 1^st phase of the XENON program is well underway, with a 10 kg TPC (XENON10) currently operating underground at the Italian Gran Sasso Laboratory (LNGS). The detector, built at Nevis Labs, was moved in March 2006 and it has been running continuously and stably for the past five months in dark matter search mode. First results from this experiment are expected by Spring 2007. The Picture Gallery has a selection of images on the XENON10 experiment and its people, both at Nevis and at LNGS.

XENON has been supported by the National Science Foundation since 2002 and, more recently, by the Department of Energy as well.The current collaboration, which I have led since the experiment was first proposed, involves groups at: Aachen (Germany), Coimbra (Portugal), Columbia, Case Western, Brown, LNGS (Italy), LLNL, Rice and Yale.The next phase of the experiment, which will develop a detector with ~100 kg active mass (XENON100), will start in Fall 2007 with underground deployment by early 2009.The Columbia XENON Group includes: a senior scientist, a research scientist, 2 postdocs, 2 graduate students and undergraduates. In addition to playing a leading role in the XENON10 underground operation, data analysis and interpretation, we maintain an active R&D program to test and apply new technologies for improved performance of LXe scintillation and ionization detectors for dark matter and other applications.

One very exciting research activity involves new type of photo-devices (compact PMTs, LAAPDs, SiPMTs, MCP-PMTs) for the detection of the VUV Xe light.This is in connection with my longstanding interest in MeV gamma-ray astrophysics with an Advanced Compton Telescope (ACT) based on a LXeTPC.The first LXeTPC for Compton imaging of cosmic gamma rays was developed by my group at the Columbia Astrophysics Laboratory, with support from NASA. The TPC as the central detector of the balloon-borne Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) was tested in two balloon flights in 1999 and 2000, demonstrating for the first time the application of this detector technology for observations of cosmic gamma rays. In collaboration with Rice University, we continue the development of an LXeTPC for spectroscopy and imaging of gamma ray lines and continuum emission from a variety of astrophysical sources. Columbia is a member of the ACT collaboration, which has recently completed a Vision Mission Study for NASA with the goal of a satellite mission in 2015.

SELECTED PUBLICATIONS:

E. Aprile, C. E. Dahl, L. DeViveiros, R. Gaitskell, K. L. Giboni, J. Kwong, P. Majewski, K. Ni, T. Shutt, M. Yamashita
“Simultaneous Measurement of Ionization and Scintillation from Nuclear Recoils in Liquid Xenon as Target for a Dark Matter Experiment,'' Phys. Rev. Lett, 97, 081302 (2006).

E. Aprile, P. Cushman, K. Ni, P. Shagin
“Detection of Liquid Xenon Scintillation Light with a Silicon Photomultiplier,”
Nucl. Instr. and Meth. A 556 (2006) 215.

E. Aprile, K. L. Giboni, P. Majewski, K. Ni, M. Yamashita, R. Hasty, A.Manzur, D. N. McKinsey
“Response of Liquid Xenon to Low Energy Nuclear Recoils,'' Phys. Rev. D, 72, 072006 (2005).

K. Ni, E. Aprile, D. Day, K.L. Giboni, J.A.M. Lopes, P. Majewski, M. Yamashita
“Performance of a Large Area Avalanche Photodiode in a Liquid Xenon Ionization and Scintillation Chamber,'' Nucl. Instr. and Meth. A, 551 (2005) 356.

K.-L. Giboni, E. Aprile, P.Majewski, K. Ni, M. Yamashita
“Fast Timing Measurements of Gamma-Ray Events in Liquid Xenon”
IEEE Transactions on Nuclear Science, Volume 52, Issue 5 (2005) 1800.

S. E. Boggs, et al.
“The Advanced Compton Telescope Mission,”
NASA Vision Mission Concept Study Report, (2006),astro-ph/0608532; New Astronomy Reviews, 50 (2006) 604.

E. Aprile, A.E. Bolotnikov, A.I. Bolozdynya, & T. Doke
Noble Gas Detectors, WILEY-VCH Verlag GmbH & Co. ISBN: 3-527-40597-6 (2006)

E. Aprile, J. Angle, F. Arneodo, L. Baudis, A. Bernstein, A. Bolozdynya, P. Brusov, L. C. C. Coelho, C. E. Dahl, L. DeViveiros, A. D. Ferella, L. M. P. Fernandes, S. Fiorucci, R. J. Gaitskell, K. L. Giboni, R. Gomez,10 R. Hasty, L. Kastens, J. Kwong, J. A. M. Lopes, N. Madden, A. Manalaysay, A. Manzur, D. N. McKinsey, M. E. Monzani, K. Ni, U. Oberlack, J. Orboeck, G. Plante, R. Santorelli, J. M. F. dos Santos, P. Shagin,T. Shutt, P. Sorensen, S. Schulte, C. Winant, and M. Yamashita

"First Results from the XENON10 Dark Matter Experiment at the Gran Sasso National Laboratory"  Physical Review Letter 100, 021303 (2008)