We measured the nuclear-recoil ionization yield in silicon with a cryogenic phonon-sensitive gram-scale detector. Neutrons from a mono-energetic beam scatter off of the silicon nuclei at angles ...corresponding to energy depositions from 4 keV down to 100 eV, the lowest energy probed so far. The results show no sign of an ionization production threshold above 100 eV. In conclusion, these results call for further investigation of the ionization yield theory and a comprehensive determination of the detector response function at energies below the keV scale.
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ...ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e / ( 3 × 105), as well as the strongest limits for charge ≤ e / 160 , with a minimum vertical intensity of 1.36 × 10−7 cm−2 s−1 sr−1 at charge e / 160 . These results apply over a wide range of LIP masses ( 5 MeV / c2 to 100 TeV / c2) and cover a wide range of β γ values ( 0.1 – 106), thus excluding nonrelativistic LIPs with β γ as small as 0.1 for the first time.
We estimate the amount of Ar37 produced in natural xenon via cosmic-ray-induced spallation, an inevitable consequence of the transportation and storage of xenon on the Earth’s surface. We then ...calculate the resulting Ar37 concentration in a 10-tonne payload (similar to that of the LUX-ZEPLIN experiment) assuming a representative schedule of xenon purification, storage, and delivery to the underground facility. Using the spallation model by Silberberg and Tsao, the sea-level production rate of Ar37 in natural xenon is estimated to be 0.024 atoms/kg/day. Assuming the xenon is successively purified to remove radioactive contaminants in 1-tonne batches at a rate of 1 tonne/month, the average Ar37 activity after 10 tons are purified and transported underground is 0.058-0.090 μBq/kg, depending on the degree of argon removal during above-ground purification. Such cosmogenic Ar37 will appear as a noticeable background in the early science data, while decaying with a 35-day half-life. This newly noticed production mechanism of Ar37 should be considered when planning for future liquid-xenon-based experiments.
Initial performance of the CUORE-0 experiment Artusa, D. R.; Avignone, F. T.; Azzolini, O. ...
European physical journal. C, Particles and fields,
08/2014, Letnik:
74, Številka:
8
Journal Article
Recenzirano
Odprti dostop
CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of
130
Te
. We present the first data analysis with
7.1
kg
·
y
of total
...TeO
2
exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to
2.57
MeV
) and in the
α
background-dominated region (2.70 to
3.90
MeV
) have been measured to be
0.071
±
0.011
and
0.019
±
0.002
counts
/
(
keV
·
kg
·
y
)
, respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is
5.7
keV
. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this article we describe the background challenges for the CUORE experiment posed by surface contamination of inert detector materials such as copper, and present three techniques explored to ...mitigate these backgrounds. Using data from a dedicated test apparatus constructed to validate and compare these techniques we demonstrate that copper surface contamination levels better than 10−7- 10−8 Bq/cm2 are achieved for 238U and 232Th. If these levels are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit on the number of background counts in the region of interest is 0.02–0.03 counts/keV/kg/y depending on the adopted mitigation technique.
CUORE sensitivity to $$0\nu \beta \beta $$ decay Alduino, C.; Alfonso, K.; Artusa, D. R. ...
European physical journal. C, Particles and fields,
08/2017, Letnik:
77, Številka:
8
Journal Article
Recenzirano
Odprti dostop
We report a study of the CUORE sensitivity to neutrinoless double beta (0νββ) decay. We used a Bayesian analysis based on a toy Monte Carlo (MC) approach to extract the exclusion sensitivity to the ...0νββ decay half-life (T1/20ν) at 90% credibility interval (CI) – i.e. the interval containing the true value of T1/20ν with 90% probability – and the 3σ discovery sensitivity. We consider various background levels and energy resolutions, and describe the influence of the data division in subsets with different background levels. If the background level and the energy resolution meet the expectation, CUORE will reach a 90% CI exclusion sensitivity of 2·1025 year with 3 months, and 9·1025 year with 5 years of live time. Under the same conditions, the discovery sensitivity after 3 months and 5 years will be 7·1024 year and 4·1025 year, respectively.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► Measurement of radioactive contaminations of TeO2 crystals for the CUORE experiment. ► Both bulk and surface contamination from 238U and 232Th decay chains is not found. ► The upper limits are ...calculated to be within the contract specification. ► An extrapolation to CUORE background from bulk and surface contamination is performed.
The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO2 crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed.
The CUORE Detector and Results Nutini, Irene; Adams, D. Q.; Alfonso, K. ...
Journal of low temperature physics,
2020/4, Letnik:
199, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
The cryogenic underground observatory for rare events (CUORE) is a cryogenic experiment searching for neutrinoless double beta decay (
0
ν
β
β
) of
130
Te
. The detector consists of an array of
988
...TeO
2
crystals arranged in a compact cylindrical structure of 19 towers. We report the CUORE initial operations and optimization campaigns. We then present the CUORE results on
0
ν
β
β
and
2
ν
β
β
decay of
130
Te
obtained from the analysis of the physics data acquired in 2017.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. In this work, a brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
PDF
