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ABSTRACT: As a first development of a bolometric dark matter detection experiment,
preliminary radioactive background measurements, down to 3 keV, are
performed using a 24 g sapphire crystal cooled at 55 mK. The experiment
is operated in a deep underground laboratory (Laboratoire Souterrain de
Modane) in order to eliminate the cosmic ray background. Due to the low
energy threshold it is shown that, for low mass dark matter particles
(less than or = 10 GeV/sq c), bolometers are potentially better than the
conventional semi-conductor (Si, Ge) or scintillating (NaI) detectors.
Astronomy and Astrophysics 10/1993; 278:L31-L34. · 4.59 Impact Factor
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Archives internationales de physiologie et de biochimie 02/1963; 71:73-82.
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S. Cebrián,
N. Coron,
G. Dambier,
E. García,
D. González,
I.G. Irastorza, J. Leblanc,
P. de Marcillac,
A. Morales,
J. Morales,
A.Ortiz de Solórzano,
J. Puimedón,
A. Salinas,
M.L. Sarsa,
S. Scopel,
J.A. Villar
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ABSTRACT: A cryogenic search for WIMP Dark Matter with small sapphire bolometers through the WIMP scattering off Al2O3 nuclei, the ROSEBUD (Rare Objects SEarch with Bolometers UndergrounD) experiment, is being installed in the Canfranc Underground Laboratory (Spain) at 2450 m water equivalent. The performances of the bolometers, the radioactive background expected from the measurement of the radiopurity of the ROSEBUD components and the estimated sensitivity of the experiment for low mass WIMP detection are presented.
Astroparticle Physics.
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ABSTRACT: The aim of this study was to determine if carnosine, a dipeptide composed of histidine and β-alanine, had some influence on pancreatic hormone secretion in dogs. Sixty to 90 minutes after the ingestion of 1 g of carnosine significant increases in plasma insulin and glucagon were observed. Comparable results were obtained with i.v.. injection of 0.5 g of histidine which is the amount contained in 1 g of carnosine. Injection of 0.5 g of β-alanine or of 0.5 g of β-alanine with 0.5 g of histidine had no effect. Similarly no response was obtained with i.v. injection of 1 g of carnosine. The fact that the stimulation of insulin and glucagon secretion by ingestion of carnosine but not by i.v. injection indirectly support the presence of carnosinase in the gut but not in the plasma. These results suggest that the increased hormonal secretion observed is not due to carnosine “per se” but is mediated instead by its histidine content. It is also suggested that the increase in insulin secretion following the ingestion of a meat meal could be related to its carnosine content. A possible implication of these findings is that the insulin and glucagon secretion following the ingestion of meat meals could be related in part to their histidine content as a component of carnosine.
Nutrition Research.
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ABSTRACT: The bolometric properties of a 2 g LiF single crystal have been investigated below 100 mK under alpha and thermal neutron irradiation. The reported energy resolution at 5 MeV on both alphas and the neutron capture line of the n(6Li, α)t reaction is 16 keV FWHM. Evidence is given for a dependence of the thermal response on the nature of the absorbed radiation. Light emission of undoped LiF has been investigated down to 10 K under gamma and alpha irradiation. We discuss the possibility to use LiF bolometers in dark matter detection experiments and neutron spectrometry.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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S. Cebrián,
N. Coron,
G. Dambier,
E. Garcı́a,
D. González,
I.G. Irastorza, J. Leblanc,
P. de Marcillac,
A. Morales,
J. Morales,
A. Ortiz de Solórzano,
A. Peruzzi,
J. Puimedón,
M.L. Sarsa,
S. Scopel,
J.A. Villar
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ABSTRACT: ROSEBUD (Rare Objects SEarch with Bolometers UndergrounD) is an experiment which attempts to detect low mass weak interacting massive particles through their elastic scattering off Al and O nuclei. It consists of three small sapphire bolometers (of a total mass of 100 g) with NTD-Ge sensors in a dilution refrigerator operating at 20 mK in the Canfranc Underground Laboratory. We report in this paper the results of several runs (of about 10 days each) with successively improved energy thresholds, and the progressive background reduction obtained by improvement of the radiopurity of the components and subsequent modifications in the experimental assembly, including the addition of old lead shields. Mid-term plans and perspectives of the experiment are also presented.
Astroparticle Physics.
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ABSTRACT: Concentration of cholecystokinin was measured by radioimmunoassay in 29 discrete brain nuclei of rats fed with purina chow or a highly palatable diet given ad libitum or in restricted amounts. The cholecystokinin content was increased only in nucleus olfactorius anterior of rats fed with palatable food, suggesting that peptide may play an important role in taste and smell.
Brain Research.
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C. Bobin,
N. Coron,
G. Dambier,
E. García,
C. Goldbach,
D. González, J. Leblanc,
P. de Marcillac,
A. Morales,
J. Morales,
G. Nollez,
A. Ortiz de Solórzano,
J. Puimedón,
A. Salinas,
M.L. Sarsa,
S. Scopel,
J.A. Villar
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ABSTRACT: An experiment to look for light WIMPs with sapphire bolometers is to be installed in the Canfranc Underground Laboratory (at 2450 m.w.e) in the Spanish Pyrenees. In the first stage two small 25g bolometers with NTD-Ge sensors, operating at 25mK, with an energy threshold of 300eV and FWHM energy resolution of 120eV at 1.5keV will perform a background test experiment. The features of the bolometers, the radioactivity measurements of the components and the set-up and status of the experiment are reported.
Nuclear Physics B - Proceedings Supplements.
