27 research outputs found
Cryogenic bath-type heat exchangers for ultra-pure noble gas applications
Two cryogenic bath-type heat exchangers for ultra-pure noble gas applications were developed with particular emphasis on noble gas liquefaction in cryogenic distillation systems. The main objective was to construct heat exchangers for xenon from materials that do not emanate radon and that fulfill ultra-high vacuum standards. Therefore, only high-quality copper and stainless steel materials were used. Especially, large-area oxygen-free copper fins with high conductivity in a new design ensure efficient heat transfer. One bath-type Xe-Xe heat exchanger was designed with a diameter of 50 cm to achieve a xenon condensing capacity of at least 100 kg/h. In order to guarantee the necessary heat transfer between the two xenon reservoirs, this heat exchanger features a specially manufactured stainless steel flange with a copper plate welded inside. We first tested our concept on a dedicated bath-type heat exchanger with a reduced diameter of 30 cm using liquid nitrogen to liquefy the xenon. A model based on conservative assumptions such as film boiling on the nitrogen side and film condensation on the xenon side was developed and applied to caluclate the expected heat transfer for our design. We were able to demonstrate an adjustable xenon liquefaction rate of up to 113 kg/h limited only by our measurement procedure at a cooling efficiency of (0.98 ± 0.03) for the LN-Xe heat exchanger
Glass resistive plate chambers in the OPERA experiment
Abstract OPERA is an underground neutrino oscillation experiment to search for ν τ appearance from a pure ν μ beam produced at CERN. To flag the events due to the neutrino interactions with the rock surrounding the OPERA detector, a large VETO system, based on the use of Glass Resistive Plate Chambers (GRPC) has been realized. We describe the detectors, the tests performed before the installation in the underground laboratories and the monitor system for the water pollution in the GRPC gas mixture
The CUORE cryostat: an infrastructure for rare event searches at millikelvin temperatures
The CUORE experiment is the world's largest bolometric experiment. The
detector consists of an array of 988 TeO2 crystals, for a total mass of 742 kg.
CUORE is presently taking data at the Laboratori Nazionali del Gran Sasso,
Italy, searching for the neutrinoless double beta decay of 130Te. A large
custom cryogen-free cryostat allows reaching and maintaining a base temperature
of about 10 mK, required for the optimal operation of the detector. This
apparatus has been designed in order to achieve a low noise environment, with
minimal contribution to the radioactive background for the experiment. In this
paper, we present an overview of the CUORE cryostat, together with a
description of all its sub-systems, focusing on the solutions identified to
satisfy the stringent requirements. We briefly illustrate the various phases of
the cryostat commissioning and highlight the relevant steps and milestones
achieved each time. Finally, we describe the successful cooldown of CUORE
Design and Performance of the XENON10 Dark Matter Experiment
XENON10 is the first two-phase xenon time projection chamber (TPC) developed
within the XENON dark matter search program. The TPC, with an active liquid
xenon (LXe) mass of about 14 kg, was installed at the Gran Sasso underground
laboratory (LNGS) in Italy, and operated for more than one year, with excellent
stability and performance. Results from a dark matter search with XENON10 have
been published elsewhere. In this paper, we summarize the design and
performance of the detector and its subsystems, based on calibration data using
sources of gamma-rays and neutrons as well as background and Monte Carlo
simulations data. The results on the detector's energy threshold, energy and
position resolution, and overall efficiency show a performance that exceeds
design specifications, in view of the very low energy threshold achieved (<10
keVr) and the excellent energy resolution achieved by combining the ionization
and scintillation signals, detected simultaneously
Muon Energy Estimate Through Multiple Scattering with the Macro Detector
Muon energy measurement represents an important issue for any experiment
addressing neutrino induced upgoing muon studies. Since the neutrino
oscillation probability depends on the neutrino energy, a measurement of the
muon energy adds an important piece of information concerning the neutrino
system. We show in this paper how the MACRO limited streamer tube system can be
operated in drift mode by using the TDC's included in the QTPs, an electronics
designed for magnetic monopole search. An improvement of the space resolution
is obtained, through an analysis of the multiple scattering of muon tracks as
they pass through our detector. This information can be used further to obtain
an estimate of the energy of muons crossing the detector. Here we present the
results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines,
to provide a full check of the electronics and to exploit the feasibility of
such a multiple scattering analysis. We show that by using a neural network
approach, we are able to reconstruct the muon energy for 40 GeV. The
test beam data provide an absolute energy calibration, which allows us to apply
this method to MACRO data.Comment: 25 pages, 11 figures, Submitted to Nucl. Instr. & Meth.
CUORE-0 detector: design, construction and operation
The CUORE experiment will search for neutrinoless double-beta decay ofTe with an array of 988 TeO bolometers arranged in 19 towers.CUORE-0, the first tower assembled according to the CUORE procedures, was builtand commissioned at Laboratori Nazionali del Gran Sasso, and took data fromMarch 2013 to March 2015. In this paper we describe the design, constructionand operation of the CUORE-0 experiment, with an emphasis on the improvementsmade over a predecessor experiment, Cuoricino. In particular, we demonstratewith CUORE-0 data that the design goals of CUORE are within reach
CUORE Experiment: The Search for Neutrrinoless Double Beta Decay
The main purpose of the Cryogenic Underground Observatory for Rare Events (CUORE) experiment is the search for the Neutrinoless Double Beta Decay (0νDBD) of n130Te reaching a sensitivity on Majorana mass better than 50 meV. Cuoricino represents not only the first stage of CUORE, but also the most massive 0νDBD experiment presently running. Present results and future planning of these experiments will be described in the paper
Muon Energy Estimate through Multiple Scattering with the MACRO detector
Abstract Muon energy measurement represents an important issue for any experiment addressing neutrino-induced up-going muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube system can be operated in drift mode by using the TDCs included in the QTPs, an electronics designed for magnetic monopole search. An improvement of the space resolution is obtained, through an analysis of the multiple scattering of muon tracks as they pass through our detector. This information can be used further to obtain an estimate of the energy of muons crossing the detector. Here we present the results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines, to provide a full check of the electronics and to exploit the feasibility of such a multiple scattering analysis. We show that by using a neural network approach, we are able to reconstruct the muon energy for E m o40 GeV: The test beam data provide an absolute energy calibration, which allows us to apply this method to MACRO data.
Cryogenic bath-type heat exchangers for ultra-pure noble gas applications
International audienceTwo cryogenic bath-type heat exchangers for ultra-pure noble gas applications were developed with particular emphasis on noble gas liquefaction in cryogenic distillation systems. The main objective was to construct heat exchangers for xenon from materials that do not emanate radon and that fulfill ultra-high vacuum standards. Therefore, only high-quality copper and stainless steel materials were used. Especially, large-area oxygen-free copper fins with high conductivity in a new design ensure efficient heat transfer. One bath-type Xe-Xe heat exchanger was designed with a diameter of 50 cm to achieve a xenon condensing capacity of at least 100 kg/h. In order to guarantee the necessary heat transfer between the two xenon reservoirs, this heat exchanger features a specially manufactured stainless steel flange with a copper plate welded inside. We first tested our concept on a dedicated bath-type heat exchanger with a reduced diameter of 30 cm using liquid nitrogen to liquefy the xenon. A model based on conservative assumptions such as film boiling on the nitrogen side and film condensation on the xenon side was developed and applied to caluclate the expected heat transfer for our design. We were able to demonstrate an adjustable xenon liquefaction rate of up to 113 kg/h limited only by our measurement procedure at a cooling efficiency of (0.98 ± 0.03) for the LN-Xe heat exchanger