Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experiment

Aguilar-Arevalo, A. A.; Amidei, D.; Bertou, X.; Bole, David G.; Butner, Melissa; Cancelo, Gustavo; Vázquez, A.; Chavarría, Á.; Neto, J. R. T. de Mello; Dixon, S.; D’Olivo, Juan Carlos; Estrada, J.; Moroni, Guillermo Fernández; Torres, K.; Izraelevitch, Federico; Kavner, A.; Kilminster, B.; Lawson, I.; Liao, J.; López, Marcos Miralles; Molina, Jorge; Moreno-Granados, G.; Pena, J.; Privitera, P.; Sarkis, Y.; Scarpine, V.; Schwarz, T.; Haro, Miguel Sofo; Tiffenberg, J.; Machado, D. Torres; Trillaud, F.; You, X. P.; Zhou, Jing

doi:10.1088/1748-0221/10/08/p08014

Cited by 57 publications

(55 citation statements)

References 23 publications

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“…a Typical isotopic composition of enriched germanium used in double beta decay searches is 86% of 76 Ge and 14% of 74 Ge.…”

Section: Germaniummentioning

confidence: 99%

“…It was checked that, in general, estimates based on the Gordon et al spectrum are closer to available experimental results; the uncertainty in the activation yields coming from the cosmic ray flux was for most of the analyzed products below a factor 2. • Neutron irradiation experiments have been performed on enriched germanium to determine the neutron radiative-capture cross sections on 74 Ge and 76 Ge, for neutron thermal energies 62,63 and energies of the order of a few MeV. 64 These results are of special interest for double beta decay experiments like GERDA and Majorana.…”

Section: Germaniummentioning

confidence: 99%

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Cosmogenic activation of materials

Cebrián¹

2013

AIP Conference Proceedings

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Experiments looking for rare events like the direct detection of dark matter particles, neutrino interactions or the nuclear double beta decay are operated deep underground to suppress the effect of cosmic rays. But the production of radioactive isotopes in materials due to previous exposure to cosmic rays is an hazard when ultra-low background conditions are required. In this context, the generation of long-lived products by cosmic nucleons has been studied for many detector media and for other materials commonly used. Here, the main results obtained on the quantification of activation yields on the Earth's surface will be summarized, considering both measurements and calculations following different approaches. The isotope production cross sections and the cosmic ray spectrum are the two main ingredients when calculating this cosmogenic activation; the different alternatives for implementing them will be discussed. Activation that can take place deep underground mainly due to cosmic muons will be briefly commented too. Presently, the experimental results for the cosmogenic production of radioisotopes are scarce and discrepancies between different calculations are important in many cases, but the increasing interest on this background source which is becoming more and more relevant can help to change this situation.

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“…a Typical isotopic composition of enriched germanium used in double beta decay searches is 86% of 76 Ge and 14% of 74 Ge.…”

Section: Germaniummentioning

confidence: 99%

Section: Germaniummentioning

confidence: 99%

Cosmogenic activation of materials

Cebrián¹

2013

AIP Conference Proceedings

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“…3. We leave to future work calculating the limits from DarkSide-50 [14], CDMS-HVeV [13], and DAMIC at SNOLAB [16]. We also show the 90% C.L.…”

mentioning

confidence: 95%

“…In all cases the entire energy of relative motion between the atom and DM can in principle be transferred to the outgoing photon or electron. These signals have already opened a new pathway for current detectors to register DM scattering on nuclei [4][5][6][7] for DM masses below 100 MeV (driven primarily by the stronger Migdal effect), and DM scattering on electrons [8][9][10][11][12][13][14][15][16] for masses as low as 500 keV. The sensitivity to sub-GeV DM is expected to improve significantly over the next few years as new detectors with an ultralow ionization threshold are being developed [10,17].…”

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confidence: 99%

Relation between the Migdal Effect and Dark Matter-Electron Scattering in Isolated Atoms and Semiconductors

et al. 2020

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A key strategy for the direct detection of sub-GeV dark matter is to search for small ionization signals. These can arise from dark matter-electron scattering or when the dark matter-nucleus scattering process is accompanied by a "Migdal" electron. We show that the theoretical descriptions of both processes are closely related, which allows for a principal mapping between dark matterelectron and dark matter-nucleus scattering rates once the dark matter interactions with matter are specified. We explore this parametric relationship for noble-liquid targets and, for the first time, provide an estimate of the "Migdal" ionization rate in semiconductors that is based on evaluating a crystal form factor that accounts for the semiconductor band structure. We also present new darkmatter-nucleus scattering limits down to dark matter masses of 500 keV using published data from XENON10, XENON100, and a SENSEI prototype Skipper-CCD. For a dark photon mediator, the dark matter-electron scattering rates dominate over the Migdal rates for dark matter masses below 100 MeV. We also provide projections for proposed experiments with xenon and silicon targets.

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“…Although our treatment here has focused on scattering from isolated atoms, we note that additional ionization from Migdal scattering should also contribute in semiconductor targets (mainly Si and Ge), for which low electronic band gaps represent the next frontier in electronionization direct detection. This additional signal channel can be probed by numerous future and ongoing experiments, including DAMIC at SNOLAB [80], SEN-SEI [26], SuperCDMS [24], and DAMIC-M [81]. However, a proper comparison of electron scattering and Migdal scattering in such materials is beyond the scope of the present work and deserves a dedicated study.…”

Section: Results and Conclusionmentioning

confidence: 95%

Electron ionization via dark matter-electron scattering and the Migdal effect

2020

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There are currently several existing and proposed experiments designed to probe sub-GeV dark matter (DM) using electron ionization in various materials. The projected signal rates for these experiments assume that this ionization yield arises only from DM scattering directly off electron targets, ignoring secondary ionization contributions from DM scattering off nuclear targets. In this work we investigate the validity of this assumption and show that if sub-GeV DM couples with comparable strength to both protons and electrons, as would be the case for a dark photon mediator, the ionization signal from atomic scattering via the Migdal effect scales with Z 2 (me/mN ) 2 q 2 where mN is the mass of the target nucleus and q is the 3-momentum transferred to the atom. The result is that the Migdal effect is always subdominant to electron scattering when the mediator is light, but that Migdal-induced ionization can dominate over electron scattering for heavy mediators and DM masses in the hundreds of MeV range. We put these two ionization processes on identical theoretical footing, address some theoretical uncertainties in the choice of atomic wavefunctions used to compute rates, and discuss the implications for DM scenarios where the Migdal process dominates, including for XENON10, XENON100, and the recent XENON1T results on light DM

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Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experiment

Cited by 57 publications

References 23 publications

Cosmogenic activation of materials

Cosmogenic activation of materials

Relation between the Migdal Effect and Dark Matter-Electron Scattering in Isolated Atoms and Semiconductors

Electron ionization via dark matter-electron scattering and the Migdal effect

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