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Ph.D., University of Geneva, Switzerland, 1982
Link to CV
My research is currently focused on understanding Dark Matter through a direct detection experiment, named XENON. The existence of Dark Matter is undisputed, yet its nature remains mysterious and unexplained. The explanation is likely to involve physics beyond the standard model of particle physics (BSM). Weakly interacting massive particles (WIMPs) are one class of dark matter candidates, naturally predicted in BSM theories. WIMPs direct detection experiments such as XENON aim to measure the signals produced in a detector on Earth as a result of a WIMP-nucleon scattering. To be sensitive to such rare events, an experiment must rely on a very large target mass, extremely low background and effective signal-to-noise discrimination. XENON used liquid xenon as WIMP target and detection medium in a 3D position sensitive Time Projection Chamber (TPC). With TPCs of increasing mass and reduced background, the XENON project has been at the forefront of direct detection experiments worldwide. Results from the XENON100 detector, at the Italian Gran Sasso Laboratory (LNGS), have yielded the most stringent limits on both spin-independent and spin-dependent WIMP-nucleon cross-section. The search for dark matter continues with XENON1T, the first experiment to use a TPC with several tons of ultra-pure Xe with unprecedented low background and sensitivity reach. XENON1T , also located at the LNGS laboratory, was completed in early 2016 and is currently taking data. XENON is funded by the National Science Foundation.
An active R&D program is an integral part of my research. The present experiments aim to measure with increasing precision the properties of liquid xenon under different particle irradiation, both for the benefit of the XENON program but also for other applications where combined calorimetry and imaging are of interest. The experiments are carried out in my Noble Liquid Detectors Laboratory on the 10 floor of the Pupin physics building, on the Columbia's Morningside Heights campus in Manhattan. Another project , also of interest to XENON, uses an Atom Trap to measure traces of Krypton in Xenon at better than 1 part per trillion. The Columbia Atom Trap Trace Analysis was built as a Major Research Infrastructure project, funded by NSF and Columbia University. It is now located in the Cyclotron building of the Columbia University Nevis Laboratories in Irvington, NY.
1. E. Aprile et al. “Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data”, arXiv:1701.00769 (2017).
2. E. Aprile et al. “XENON100 dark matter results from a combination of 477 live days”, Phys. Rev. D 94, 122001 (2016).
3. E. Aprile et al. “Removing krypton from xenon by cryogenic distillation to the ppq level”, arXiv:1612.04284 (2016).
4. E. Aprile et al. “Low-mass dark matter search using ionization signals inXENON100”, Phys. Rev. D 94, 092001(2016).
5. J. Aalbers, (XENON Collaboration), “DARWIN: towards the ultimate dark matter detector”, JCAP11(2016)017.
6. L. W. Goetzke (Columbia XENON), “Measurement of light and charge yield of low-energy electronic recoils in liquid xenon”, arXiv:1611.10322 (2016).
7. E. Aprile et al. “Results from a Calibration of XENON100 Using a Source of Dissolved Radon-220”, arXiv:1611.03585 (2016).
8. E. Aprile et al. “Search for Two-Neutrino Double Electron Capture of 124Xe with XENON100”, arXiv:1609.03354 (2016).