Fabrication and response of high concentration SIMPLE superheated droplet detectors with different liquids

Felizardo, M.; Morlat, T.; Marques, J.G.; Ramos, A.R.; Girard, T.A.; Fernandes, A.C.; Kling, A.; Lázaro, Ignacio; Martins, Rui C.; Puibasset, Joël

doi:10.1016/j.astropartphys.2013.08.006

Cited by 14 publications

(10 citation statements)

References 54 publications

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“…where K is the acoustic power of the event, c is the speed of sound in the liquid, τ is the expansion time of the bubble, and V = 4π 3 r 3 is the droplet volume. An estimate of the pressure change at the microphone in a SDD is obtained [22,31], again with Refs. [24][25][26], as A ∼ 6.2 × 10 2 µbar, so that the microphone sensitivity yields a nucleation signal A ∼ 1000 mV at 1 kHz for droplet radii 30 µm.…”

Section: B Signal Analysismentioning

confidence: 99%

“…[24][25][26], as A ∼ 6.2 × 10 2 µbar, so that the microphone sensitivity yields a nucleation signal A ∼ 1000 mV at 1 kHz for droplet radii 30 µm. The complete phase transition of a droplet results in a gas bubble harmonically oscillating about its equilibrium radius, with a resonant frequency depending on the elasticity of the gel as well as thermodynamic properties of both phases [31], and is estimated at ∼ 700 Hz for C 2 ClF 5 with typical operating parameters at T,P [32].…”

Section: B Signal Analysismentioning

confidence: 99%

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The SIMPLE Phase II dark matter search

Felizardo

Marques

Ramos³

et al. 2014

Phys. Rev. D

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Phase II of SIMPLE (Superheated Instrument for Massive ParticLe Experiments) searched for astroparticle dark matter using superheated liquid C2ClF5 droplet detectors. Each droplet generally requires an energy deposition with linear energy transfer (LET) > ∼ 150 keV/µm for a liquid-to-gas phase transition, providing an intrinsic rejection against minimum ionizing particles of order 10 −10 , and reducing the backgrounds to primarily α and neutron-induced recoil events. The droplet phase transition generates a millimetric-sized gas bubble which is recorded by acoustic means. We describe the SIMPLE detectors, their acoustic instrumentation, and the characterizations, signal analysis and data selection which yield a particle-induced, "true nucleation" event detection efficiency of better than 97% at a 95% C.L. The recoil-α event discrimination, determined using detectors first irradiated with neutrons and then doped with alpha emitters, provides a recoil identification of better than 99%; it differs from those of COUPP and PICASSO primarily as a result of their different liquids with lower critical LETs. The science measurements, comprising two shielded arrays of fifteen detectors each and a total exposure of 27.77 kgd, are detailed. Removal of the 1.94 kgd Stage 1 installation period data, which had previously been mistakenly included in the data, reduces the science exposure from 20.18 to 18.24 kgd and provides new contour minima of σp = 4.3 × 10 −3 pb at 35 GeV/c 2 in the spin-dependent sector of WIMP-proton interactions and σN = 3.6 × 10 −6 pb at 35 GeV/c 2 in the spin-independent sector. These results are examined with respect to the fluorine spin and halo parameters used in the previous data analysis.

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Section: B Signal Analysismentioning

confidence: 99%

Section: B Signal Analysismentioning

confidence: 99%

The SIMPLE Phase II dark matter search

Felizardo

Marques

Ramos³

et al. 2014

Phys. Rev. D

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“…For R-12 SDDs there is a decrease of about 80% in f values compared to those of R-134A and R-1216 SDDs for which the change is about 45% in the pressure range studied here. In literature there are reports of both increase [11] and decrease [24] of f values with increase in applied pressure. Here for all the three SDDs we have observed the reduction of f values with increase in pressure.…”

Section: Discussionmentioning

confidence: 99%

Study of acoustic emission due to vaporisation of superheated droplets at higher pressure

2017

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The bubble nucleation in superheated liquid can be controlled by adjusting the ambient pressure and temperature. At higher pressure the threshold energy for bubble nucleation increases and we have observed that the amplitude of the acoustic emission during vaporisation of superheated droplet decreases with increase in pressure at any given temperature. Other acoustic parameters such as the primary harmonic frequency and the decay time constant of the acoustic signal also decrease with increase in pressure. It is independent of the type of superheated liquid. The decrease in signal amplitude limits the detection of bubble nucleation at higher pressure. This effect is explained by the microbubble growth dynamics in superheated liquid.

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“…The measured diameters of the individual fiber and roving are 201 m and 30020 m respectively. The gel matrix contains various materials of standard compositions [41] except for gelatin -its mass composition assumed to be 12.5% proline, 12.5% hydroxyproline, 20% glycine, 23% glutamic acid, 16% arginine and 16% alanine [42]. The superheated liquid was not included in the gel description for the MCNP simulations.…”

Section: Compositionmentioning

confidence: 99%

Neutron background signal in superheated droplet detectors of the Phase II SIMPLE dark matter search

Fernandes¹,

Kling²,

Felizardo³

et al. 2016

Astroparticle Physics

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International audienceThe simulation of the neutron background for Phase II of the SIMPLE direct dark matter search experiment is fully reported with various improvements relative to previous estimates. The model employs the Monte Carlo MCNP neutron transport code, using as input a realistic geometry description, measured radioassays and material compositions, and tabulated ( α,n ) yields and spectra. Developments include the accounting of recoil energy distributions, consideration of additional reactions and materials and examination of the relevant ( α,n ) data. A thorough analysis of the simulation results is performed that addresses an increased number of non-statistical uncertainties. The referred omissions are seen to provide a net increase of 13% in the previously-reported background estimates whereas the non-statistical uncertainty rises to 25%. The final estimated recoil event rate is 0.372 ± 0.002 (stat.) ± 0.097 (non-stat.) evt/kgd resulting in insignificant changes over the results of the experiment

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Fabrication and response of high concentration SIMPLE superheated droplet detectors with different liquids

Cited by 14 publications

References 54 publications

The SIMPLE Phase II dark matter search

The SIMPLE Phase II dark matter search

Study of acoustic emission due to vaporisation of superheated droplets at higher pressure

Neutron background signal in superheated droplet detectors of the Phase II SIMPLE dark matter search

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