Low background measurement in CANDLES-III for studying the neutrinoless double beta decay of 
Ca48

A powder synthesis of PbMoO4 from ancient lead (Pb) and deeply purified commercial MoO3 powders was performed using a wet chemistry technique to achieve the low radioactivity scintillator for neutrinoless double beta decay search in 100Mo. The synthesized powders were used to grow single crystals of PbMoO4 by a Czochralski technique in Ar environment. The luminescence and scintillation properties were measured with excitations using UV, X- and γ-rays in temperature range of 10-300 K. Annealing of the grown PMO crystal in air atmosphere enhanced the scintillation light yield by ~3 orders of magnitude compared to that measured before annealing. The scintillation light yield of grown PMO crystal at 10 K is found to be 127% to that of a reference PMO crystal under 662 keV γ-rays excitation from a 137Cs source. The background measurement of the grown crystal performed at 50 K shows negligible activity from 210Pb compared to that of reference PMO crystal. These preliminary performances show that the PMO crystal grown from ancient Pb and deeply purified MoO3 powders has the great potential to be used as cryogenic scintillator for the neutrinoless double beta decay search in 100Mo.

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APPLICATION OF MODERN STRUCTURAL MATERIALS, METHODS AND DETECTORS FOR LOW-BACKGROUND EXPERIMENTS

Bulletin of Dubna International University for Nature, Society, and Man. Series: Natural and engineering sciences ◽

10.37005/1818-0744-2020-2-29-35 ◽

2020 ◽

pp. 29-35

Author(s):

N.S. Rumyantseva ◽

K.N. Gusev

Keyword(s):

Beta Decay ◽

Background Level ◽

Structural Materials ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Background Suppression ◽

Accelerator Physics ◽

Low Background ◽

Structural Parts ◽

New Generation

Good examples of the key tasks of modern non-accelerator physics are the searches for dark matter and neutrinoless double beta decay. The essential requirement for such an experiment is the requirement of a minimal background level. The ways to reduce it are quite obvious and widely used in the ongoing experiments. So, the experiments are located in the underground laboratories, a careful selection of structural materials is carried out, and various techniques for active background suppression are used. However, in order to advance in new generation projects in addition to a serious increase in the detector mass, the significant reduction of the background level (which is already pretty low) is required. Very important irremovable background sources are the structural materials close to the detector(s). In this regard, it is extremely important not only to constantly search for new low-background materials, but also to ensure that radioactive contaminants cannot be introduced at the stage of the required parts production. In this article the results of the successful using of structural parts produced by modern methods from novel low-background materials during the preparation of the new generation ultra-low-background experiment searching for neutrinoless double beta decay are presented.

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PbMoO4 Synthesis from Ancient Lead and Its Single Crystal Growth for Neutrinoless Double Beta Decay Search

Crystals ◽

10.3390/cryst10030150 ◽

2020 ◽

Vol 10 (3) ◽

pp. 150 ◽

Cited By ~ 3

Author(s):

Arshad Khan ◽

Pabitra Aryal ◽

Hongjoo Kim ◽

Moo Hyun Lee ◽

Yeongduk Kim

Keyword(s):

Beta Decay ◽

Grown Crystal ◽

Light Yield ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Powder Synthesis ◽

Scintillation Light ◽

Air Atmosphere ◽

Background Measurement ◽

Γ Rays

A powder synthesis of PbMoO4 (PMO) from ancient lead (Pb) and deeply purified commercial MoO3 powders was performed using a wet chemistry technique to achieve the low radioactivity scintillator for neutrinoless double beta decay search in 100Mo. The synthesized powders were used to grow single crystals of PbMoO4 by the Czochralski technique in an Ar environment. The luminescence and scintillation properties were measured with excitations using UV, X- and γ-rays in the temperature range of 10–300 K. Annealing of the grown PMO crystal in an air atmosphere significantly enhanced the scintillation light yield compared to that measured before annealing. The scintillation light yield of grown PMO crystal at 10 K was found to be 127% to that of a reference PMO crystal under 662 keV γ-rays excitation from a 137Cs source. The background measurement of the grown crystal performed at 50 K shows a lower internal activity from 210Pb compared to that of reference PMO (grown from modern Pb) crystal. These preliminary performances show that the PMO crystal grown from ancient Pb and deeply purified MoO3 powders has a great potential to be used as a cryogenic scintillator for the neutrinoless double beta decay search in 100Mo.

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