CUORE: a cryogenic underground observatory for rare events Arnaboldi, C; Avignone III, F.T; Beeman, J ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
3
Journal Article
Recenzirano
Odprti dostop
CUORE is a proposed tightly packed array of 1000 TeO
2 bolometers, each being a cube
5
cm
on a side with a mass of
760
g
. The array consists of 25 vertical towers, arranged in a square of 5 towers×5 ...towers, each containing 10 layers of four crystals. The design of the detector is optimized for ultralow-background searches: for neutrinoless double-beta decay of
130
Te
(33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals
3×3×6
cm
3
of
340
g
has been completed, and a single CUORE tower is being constructed as a smaller-scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.
We describe a combined ultrasonic instrument for gas flow metering and continuous real-time binary gas composition measurements. The combined flow measurement and mixture analysis algorithm employs ...sound velocity measurements in two directions in combination with measurements of the pressure and temperature of the process gas mixture. The instrument has been developed in two geometries following extensive computational fluid dynamics studies of various mechanical layouts. A version with an axial sound path has been used with binary gas flows up to 230 1.min super(-1), while a version with a sound path angled at 45 degree to the gas flow direction has been developed for use in gas flows up to 200001.min super(-1). The instrument with the axial geometry has demonstrated a flow resolution of less than or equal to 1% of full scale for flows up to 230 1.min super(-1) and a mixture resolution of 3.10 super(-3) for C sub(3)F sub(8)/C sub(2)F sub(6) molar mixtures with similar to 20%C sub(2)F sub(6). Higher mixture precision is possible in mixtures of gases with widely-differing molecular weight (mw): a sensitivity of < 5.10 super(-5) to traces of C sub(3)F sub(8) in nitrogen (mw difference 160) has been seen in a long duration (> 1yr) continuous study. A prototype instrument with 45 degree crossing angle has demonstrated a flow resolution of 1.9% of full scale for linear flow velocities up to 15 ms super(-1). Although this development was motivated by a requirement of the ATLAS silicon tracker evaporative fluorocarbon cooling system, the developed instrument can be used in many applications where continuous knowledge of binary gas composition is required. Applications include the analysis of hydrocarbons, vapour mixtures for semi-conductor manufacture and anaesthetic gas mixtures.
We report the direct measurement of the {sup 7}Be solar neutrino signal rate performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The interaction rate of the 0.862 MeV ...{sup 7}Be neutrinos is 49{+-}3{sub stat}{+-}4{sub syst} counts/(day{center_dot}100 ton). The hypothesis of no oscillation for {sup 7}Be solar neutrinos is inconsistent with our measurement at the 4{sigma} C.L. Our result is the first direct measurement of the survival probability for solar {nu}{sub e} in the transition region between matter-enhanced and vacuum-driven oscillations. The measurement improves the experimental determination of the flux of {sup 7}Be, pp, and CNO solar {nu}{sub e}, and the limit on the effective neutrino magnetic moment using solar neutrinos.
A multiplexed system of optical fibers has been designed for the photomultiplier calibration of the Borexino experiment at Gran Sasso. Both time and energy calibration are of paramount importance in ...Borexino for the measurement of the solar
7Be neutrino flux. Equalization of photomultipliers within 1
ns is required to define a Fiducial Volume to isolate a very pure internal region of observation, and accurate energy determination and resolution are crucial for the spectral shape recognition of the neutrino signal. The size of the detector, its tightness and radiopurity constraints require special care in the material selection and mechanical handling of the system. The solution of multiplexed fiber chains has been realized for the first time in a large underground detector. In this paper we illustrate the PMT calibration system design and the results of various feasibility tests performed.
Light propagation in a large volume liquid scintillator Alimonti, G; Arpesella, C; Balata, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2000, Letnik:
440, Številka:
2
Journal Article
Recenzirano
The fluorescence light propagation in a large volume detector based on organic liquid scintillators is discussed. In particular, the effects of the fluor radiative transport and solvent Rayleigh ...scattering are emphasized. These processes have been modelled by a ray-tracing Monte Carlo method and have been experimentally investigated in the Borexino prototype which was a 4.3 ton, 4π sensitive detector. The comparison between the model prediction and the experimental data shows a satisfactory agreement indicating that the main aspects of these processes are well understood. Some features of the experimental time response of the detector are still under study.
The mechanisms of inhibition of cytomegalovirus (CMV) infection by human CD13 (aminopeptidase N)-specific antibodies were studied. These antibodies protect CD13-negative and -positive cells from CMV ...infection only if incubated with the virus inoculum, suggesting they bind to CMV virions. The association of a CD13-like molecule with virions was further supported by the transfer of CD13 immunoreactivity to the surface of CD13-negative cells upon binding of CMV; the binding of CD13-specific antibodies directly to the surface of CMV virions; and the presence of anti-CD13 immunoreactive bands, including one with mobility similar to that of native cellular CD13 on immunoblots of proteins of purified CMV particles. Importantly, CD13-specific antibodies neutralize CMV in urine of neonates with congenital CMV, indicating that the CD13-like molecule is associated with natural CMV and not acquired in vitro. These studies demonstrate that a CD13-like molecule is associated with CMV particles and may be important in CMV pathogenesis.
A chip removal facility for indium bump bonded pixel detectors Airoldi, A.; Alimonti, G.; Amati, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2005, Letnik:
540, Številka:
2
Journal Article
Recenzirano
Yield maximization in multichip hybrid pixel sensors is a crucial issue in large volume productions planned for future High-Energy Physics experiments. Bump bonding process optimization can guarantee ...statistical single bump failure rates at the acceptable level of 10–100
ppm; nevertheless, systematic effects connected to process repeatability can affect the functionality of a full chip in a module to a much larger extent. Because of this, the reversibility of the bonding procedure has been investigated. A feasibility study on single chip assemblies for the ATLAS experiment has been successfully completed, proving the possibility of reworking. As a result of it, a dedicated facility has been conceptually designed, engineered and commissioned. The characteristics of the facility in terms of motion, temperature and tensile strength control are outlined, together with the main results.
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