Discrimination between nuclear recoils and electron recoils by simultaneous detection of phonons and scintillation light

Meunier, P.; Bravin, M.; Bruckmayer, M.; Giordano, Stefano; Loidl, M.; Meier, Oliver; Pröbst, F.; Seidel, W.; Sisti, M.; Stodolsky, L.; Uchaikin, S.; Zerle, L.

doi:10.1063/1.124685

Cited by 106 publications

(88 citation statements)

References 7 publications

(7 reference statements)

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“…5 A variety of new fields for the application of these materials have emerged recently such as new generation of cryogenic detectors. 6 One reason for the particular importance of CM is based on the fact that this material is isostructural with CaWO 4 (scheelite) and exhibits sufficient light yield. 7 Thus, CM could be an excellent complementary material to calcium tungstate in a multitarget cryogenic search for dark matter.…”

Section: Introductionmentioning

confidence: 99%

Different Origins of Green-Light Photoluminescence Emission in Structurally Ordered and Disordered Powders of Calcium Molybdate

et al. 2008

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A strong greenish-light photoluminescence (PL) emission was measured at room temperature for disordered and ordered powders of CaMoO 4 prepared by the polymeric precursor method. The structural evolution from disordered to ordered powders was accompanied by XRD, Raman spectroscopy, and TEM imagery. Highlevel quantum mechanical calculations in the density functional framework were used to interpret the formation of the structural defects of disorder powders in terms of band diagram and density of states. Complex cluster vacancies) were suggested to be responsible to the appearance of new states shallow and deeply inserted in the band gap. These defects give rise to the PL in disordered powders. The natural PL emission of ordered CaMoO 4 was attributed to an intrinsic slight distortion of the [MoO 4 ] tetrahedral in the short range.

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Section: Introductionmentioning

confidence: 99%

Different Origins of Green-Light Photoluminescence Emission in Structurally Ordered and Disordered Powders of Calcium Molybdate

et al. 2008

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“…Since a nucleus and an electron or gamma of the same energy differ substantially in the yield of scintillation light, an effective background discrimination against gammas and electrons is obtained by a simultaneous measurement of the phonon and light signals. Among different scintillating crystals, CaWO 4 was selected because of its high light yield at low temperatures and the absence of a noticeable degradation of the light yield for events near the crystal surface [7]. Such a degradation, often found in coincident phonon-charge measurements and some scintillators, can cause difficulties as it may lead to a misidentification of electron/photon surface events as nuclear recoils.…”

Section: Detectorsmentioning

confidence: 99%

Limits on WIMP dark matter using scintillating CaWO4 cryogenic detectors with active background suppression

Angloher

Bucci

Christ

et al. 2005

Astroparticle Physics

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220

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We present first significant limits on WIMP dark matter by the phonon-light technique, where combined phonon and light signals from a scintillating cryogenic detector are used. Data from early 2004 with two 300 g CRESST-II prototype detector modules are presented, with a net exposure of 20.5 kg days. The modules consist of a CaWO 4 scintillating "target" crystal and a smaller cryogenic light detector. The combination of phonon and light signals leads to a strong suppression of non-nuclear recoil backgrounds. Using this information to define an acceptance region for nuclear recoils we have 16 events from the two modules, corresponding to a rate for nuclear recoils between 12 and 40 keV of (0.87± 0.22) events/(kg day). This is compatible with the rate expected from neutron background, and most of these events lie in the region of the phonon-light plane anticipated for neutron-induced recoils. A particularly strong limit for WIMPs with coherent scattering results from selecting a region of the phonon-light plane corresponding to tungsten recoils, where the best module shows zero events.

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“…An important feature of the CRESST detector modules is their ability to reject events which are not nuclear recoils via a simultaneous measurement of a heat/phonon signal in the large detector and a scintillation signal [14] in the light detector.…”

Section: Module Housingmentioning

confidence: 99%

Commissioning run of the CRESST-II dark matter search

Angloher

Bauer

Bavykina

et al. 2009

Astroparticle Physics

186

243

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The CRESST cryogenic direct dark matter search at Gran Sasso, searching for WIMPs via nuclear recoil, has been upgraded to CRESST-II by several changes and improvements. The upgrade includes a new detector support structure capable of accommodating 33 modules, the associated multichannel readout with 66 SQUID channels, a neutron shield, a calibration source lift, and the installation of a muon veto. We present the results of a commissioning run carried out in 2007.The basic element of CRESST-II is a detector module consisting of a large (∼300 g) CaWO4 crystal and a very sensitive smaller (∼ 2 g) light detector to detect the scintillation light from the CaWO4. The large crystal gives an accurate total energy measurement. The light detector permits a determination of the light yield for an event, allowing an effective separation of nuclear recoils from electron-photon backgrounds. Furthermore, information from lightquenching factor studies allows the definition of a region of the energy-light yield plane which corresponds to tungsten recoils. A neutron test is reported which supports the principle of using the light yield to identify the recoiling nucleus.Data obtained with two detector modules for a total exposure of 48 kg-days are presented. Judging by the rate of events in the "all nuclear recoils" acceptance region the apparatus shows a factor ∼ten improvement with respect to previous results, which we attribute principally to the presence of the neutron shield. In the "tungsten recoils" acceptance region three events are found, corresponding to a rate of 0.063 per kg-day. Standard assumptions on the dark matter flux, coherent or spin independent interactions, then yield a limit for WIMP-nucleon scattering of 4.8 × 10 −7 pb, at M WIMP ∼ 50 GeV.

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Discrimination between nuclear recoils and electron recoils by simultaneous detection of phonons and scintillation light

Abstract: We have developed a detector, consisting of a cryogenic calorimeter with a scintillating crystal as absorber, and a second calorimeter for the detection of the scintillation light, both operated at 12 mK. Using a CaWO 4 crystal with a mass of 6 g as

Cited by 106 publications

References 7 publications

Different Origins of Green-Light Photoluminescence Emission in Structurally Ordered and Disordered Powders of Calcium Molybdate

Different Origins of Green-Light Photoluminescence Emission in Structurally Ordered and Disordered Powders of Calcium Molybdate

Limits on WIMP dark matter using scintillating CaWO4 cryogenic detectors with active background suppression

Commissioning run of the CRESST-II dark matter search

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