Quenching Factor consistency across several NaI(Tl) crystals

TL;DR

This study measures and compares the quenching factors of five NaI(Tl) crystals under identical conditions to assess consistency, which is crucial for dark matter detection experiments like DAMA/LIBRA, ANAIS-112, and COSINE-100.

Contribution

The paper provides the first direct comparison of quenching factors across multiple NaI(Tl) crystals using a unified setup, reducing systematic uncertainties.

Findings

Quenching factors are consistent across different NaI(Tl) crystals.

No significant energy dependence of quenching factors from 10 to 80 keVnr.

Results support the assumption of uniform detector response in dark matter searches.

Abstract

Testing the DAMA/LIBRA annual modulation result independently of dark matter particle and halo models has been a challenge for twenty years. Using the same target material, NaI(Tl), is required and presently two experiments, ANAIS-112 and COSINE-100, are running for such a goal. A precise knowledge of the detector response to nuclear recoils is mandatory because this is the most likely channel to find the dark matter signal. The light produced by nuclear recoils is quenched with respect to that produced by electrons by a factor that has to be measured experimentally. However, current quenching factor measurements in NaI(Tl) crystals disagree within the energy region of interest for dark matter searches. To disentangle whether this discrepancy is due to intrinsic differences in the light response among different NaI(Tl) crystals, or has its origin in unaccounted for systematic effects will be key in the comparison among the different experiments. We present measurements of the quenching factors for five small NaI(Tl) crystals performed in the same experimental setup to control systematics. Quenching factor results are compatible between crystals and no clear dependence with energy is observed from 10 to 80 keVnr.