The authors give results of the performed comparative analysis of typical maps of interaction regimes of water droplets (recoil, scatter, breakup, and coagulation). Using a group of high-speed ...spatial video recording cameras, spatial and two-dimensional recording of collisions of droplets has been performed. The scientific novelty of the work is that the authors have corrected the ideas of the reasons for the differences of the existing maps of interaction regimes with account taken of the typical regularities of spatial recording of the droplet interaction. The most-in demand schemes of processing of experimental results have been used with account of the dimensionless angular and linear parameters of interaction, and also of the ranges of variation of the Weber number making it possible to assess the contribution of the dimensions and velocities of the droplets in determining the conditions of coagulation, recoil, scatter, and breakup in the latter. Differences of the interaction regimes in boundary (limiting) implementation conditions, and also in the number and dimensions of droplets formed upon the breakup have been singled out.
CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay (
0
ν
β
β
) of
100
Mo
. In this article, we detail the CUPID-Mo detector concept, assembly and installation in the ...Modane underground laboratory, providing results from the first datasets. The CUPID-Mo detector consists of an array of 20
100
Mo
-enriched 0.2 kg
Li
2
MoO
4
crystals operated as scintillating bolometers at
∼
20
mK
. The
Li
2
MoO
4
crystals are complemented by 20 thin Ge optical bolometers to reject
α
events by the simultaneous detection of heat and scintillation light. We observe a good detector uniformity and an excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Light collection ensures the rejection of
α
particles at a level much higher than 99.9% – with equally high acceptance for
γ
/
β
events – in the region of interest for
100
Mo
0
ν
β
β
. We present limits on the crystals’ radiopurity:
≤
3
μ
Bq/kg
of
226
Ra
and
≤
2
μ
Bq/kg
of
232
Th
. We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the
100
Mo
0
ν
β
β
decay in half-a-year’s livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology developed by the LUMINEU project and subsequently selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale bolometric
0
ν
β
β
experiment.
The authors have presented results of experimental investigations into the process of collisions of water droplets in a gas medium with variation of the basic parameters in wide ranges corresponding ...to advanced gas-vapor-droplet technologies: sizes (radii) 0.1–1 mm, velocities of travel 0–10 m/s, angles of interaction (attack) 0–90
o
, relative volume concentration 0.1–10
–3
–8.5·10
–3
m
3
of water/m
3
of the gas, velocity of motion of the flow 0–10 m/s, and temperature 20–1000
o
C; directions of flows: opposing, codirectional, and lateral. In processing the experimental results, the emphasis was on the influence of the relative volume concentrations of the droplets on the characteristics of their interaction. The relative probabilities of four typical regimes of interaction of the droplets have been calculated: recoil, coagulation, spread, and breakup (reduction in size). Parametric ranges have been shown for droplets for which the concentration growth of the latter in an aerosol leads to an increase in the probability of coagulation, recoil, and size reduction. Also, the authors have presented ranges of variation of the concentration of droplets in a gas medium, in which the probabilities of all the investigated interaction schemes are high. The experimental results have been processed with the existing approaches to generalization by calculating the angular factor of interaction and the Weber number.
A single crystal of Formula omitted (NWO) was grown by a low-thermal-gradient Czochralski technique (LTG-CZ). The scintillation properties of the crystal were evaluated for the first time as a ...potential material for dark matter search experiments. The luminescence and scintillation characteristics of the crystal were studied at room temperature and low temperatures by using a light-emitting diode (LED) and a Formula omitted beta source. The luminescence and scintillation light yield at 10 K were significantly higher than those at room temperature. The crystal showed higher light yield at 10 K than a CaMoO Formula omitted (CMO) crystal. The decay time of the crystal was investigated at temperatures between 10 and 300 K. The sensitivity to spin-independent weakly interacting massive particle-nucleon interactions based on 10 kg (2 months) and 50 kg (12 months) data for the NWO crystal detectors was estimated by a simulated experiment using the standard halo model. The luminescence, scintillation, and sensitivity results revealed that the NWO crystal is a promising candidate for a dark matter search experiment in the near future.
The advanced molybdenum-based rare process experiment (AMoRE) aims to search for neutrinoless double beta decay (
0
ν
β
β
) of
100
Mo with
∼
100
kg
of
100
Mo-enriched molybdenum embedded in cryogenic ...detectors with a dual heat and light readout. At the current, pilot stage of the AMoRE project we employ six calcium molybdate crystals with a total mass of 1.9 kg, produced from
48
Ca-depleted calcium and
100
Mo-enriched molybdenum (
48
depl
Ca
100
MoO
4
). The simultaneous detection of heat (phonon) and scintillation (photon) signals is realized with high resolution metallic magnetic calorimeter sensors that operate at milli-Kelvin temperatures. This stage of the project is carried out in the Yangyang underground laboratory at a depth of 700 m. We report first results from the AMoRE-Pilot
0
ν
β
β
search with a 111 kg day live exposure of
48
depl
Ca
100
MoO
4
crystals. No evidence for
0
ν
β
β
decay of
100
Mo is found, and a upper limit is set for the half-life of
0
ν
β
β
of
100
Mo of
T
1
/
2
0
ν
>
9.5
×
10
22
years
at 90% C.L. This limit corresponds to an effective Majorana neutrino mass limit in the range
⟨
m
β
β
⟩
≤
(
1.2
-
2.1
)
eV
.
We present the performances of a 330 g zinc molybdate (ZnMoO
4
) crystal working as scintillating bolometer as a possible candidate for a next generation experiment to search for neutrinoless double ...beta decay of
100
Mo. The energy resolution, evaluated at the 2615 keV
γ
-line of
208
Tl, is 6.3 keV FWHM. The internal radioactive contaminations of the ZnMoO
4
were evaluated as <6 μBq/kg (
228
Th) and 27±6 μBq/kg (
226
Ra). We also present the results of the
α
vs
β
/
γ
discrimination, obtained through the scintillation light as well as through the study of the shape of the thermal signal alone.
The results of the experimental studies of collisions of water and water suspension droplets in a gas medium using high-speed video recording and specialized software for tracking the initial ...droplets and the resulting fragments were presented. Videograms that illustrate the typical drop collision modes (bounce , separation, coalescence, and disruption) were given. The effects of droplet collisions under free fall conditions in air at ambient temperature (20°C) and during their motion in the counter-flows of heated air (500°C) and combustion products (800–850°C) were considered. A statistical analysis of collision modes was performed. The dependences of their occurrence on some factors (size, rate, collision angle, and criterial expressions that include the dimensionless linear and angular interaction parameters) were presented. The ranges of fluid surface area during fragmentation and separation of droplets due to collisions in gas media with different temperatures were determined.
Single crystals of lithium molybdate tungstates containing 10 and 15 mol % molybdenum were grown by the low-temperature-gradient Czochralski technique. It was shown that the single crystals have the ...phenakite structure (space group
). The heat capacity of the Li
2
W
0.85
Mo
0.15
O
4
single crystal was measured by differential scanning calorimetry in two temperature ranges: 190–370 and 320–970 K. The heat capacity in the temperature range 190–970 K is well described by the equation
C
p
= 37.95541 + 0.42875
T
− 4.87201 × 10
–4
T
2
+ 2.15184 × 10
–7
T
3
J/(K mol). It was determined that there are no phase transitions in the Li
2
W
0.85
Mo
0.15
O
4
single crystal in the studied temperature range. This makes this single crystal promising for the search for rare events, such as neutrinoless double β-decay and elastic coherent neutrino scattering off nuclei.
We investigated the conditions, characteristics, and outcomes of liquid droplet interaction in the gas medium using video frame processing. The frequency of different droplet collision outcomes and ...their characteristics were determined. Four interaction regimes were identified: bounce, separation, coalescence, and disruption. Collision regime maps were drawn up using the Weber, Reynolds, Ohnesorge, Laplace, and capillary numbers, as well as dimensionless linear and angular parameters of interaction. Significant differences were established between interaction maps under ideal conditions (two droplets colliding without a possible impact of the neighboring ones) and collision of droplets as aerosol elements. It was shown that the Weber number could not be the only criterion for changing the collision mode, and sizes and concentration of droplets in aerosols influence collision modes. It was established that collisions of droplets in a gaseous medium could lead to an increase in the liquid surface area by 1.5–5 times. Such a large-scale change in the surface area of the liquid significantly intensifies heat transfer and phase transformations in energy systems.
Cs
2
MoO
4
and Li
1.9
Cs
0.1
MoO
4
crystals were grown from melt by the low-thermal-gradient Czochralski technique. The standard formation enthalpy of cesium molybdate Cs
2
MoO
4
was measured by ...solution calorimetry. The heat capacity of Li
1.9
Cs
0.1
MoO
4
was measured by differential scanning calorimetry (DSC) in the temperature range 320–710 K. The lattice enthalpy of Cs
2
MoO
4
was calculated using the Born-Haber cycle. Cesium molybdate was shown to be thermodynamically stable to decomposition into constituent simple oxides (Cs
2
O and MoO
3
), which made it promising for application. Li
1.9
Cs
0.1
MoO
4
experienced no phase transitions in the temperature range 320–710 K.
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