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Light Concentrators for Borexino and CTF  [PDF]
L. Oberauer,C. Grieb,F. von Feilitzsch,I. Manno
Physics , 2003, DOI: 10.1016/j.nima.2004.05.095
Abstract: Light concentrators for the solar neutrino experiment Borexino and the Counting Test Facility (CTF) have been developed and constructed. They increase the light yield of these detectors by a factor of 2.5 and 8.8, respectively. Technical challenges like long term stability in various media, high reflectivity and radiopurity have been addressed and the concepts to overcome these difficulties will be described. Gamma spectroscopy measurements of the concentrators show an upper limit of 12e-6 Bq/g for uranium and a value of 120e-6 Bq/g for thorium. Upper limits on other possible contaminations like 26Al are presented. The impact of these results on the performance of Borexino and the CTF are discussed and it is shown that the design goals of both experiments are fulfilled.
The DarkSide Program at LNGS  [PDF]
Alex Wright,for the DarkSide Collaboration
Physics , 2011,
Abstract: DarkSide is a direct detection dark matter program based on two phase time projection chambers with depleted argon targets. The DarkSide detectors are designed, using novel low background techniques and active shielding, to be capable of demonstrating in situ a very low level of residual background. This means that each detector in the DarkSide program should have the ability to make a convincing claim of dark matter detection based on the observation of a few nuclear recoil events. The collaboration is currently operating a 10 kg prototype detector, DarkSide-10, in Laboratori Nazionali del Gran Sasso, Italy, while the first physics detector in the program, DarkSide-50, is expected to be deployed at LNGS at the end of 2012.
The COBRA demonstrator at the LNGS underground laboratory  [PDF]
The COBRA collaboration,J. Ebert,M. Fritts,D. Gehre,C. G??ling,T. G?pfert,C. Hagner,N. Heidrich,R. Klingenberg,T. K?ttig,K. Kr?ninger,T. Michel,T. Neddermann,C. Nitsch,C. Oldorf,T. Quante,S. Rajek,H. Rebber,O. Reinecke,K. Rohatsch,O. Schulz,A. S?rensen,I. Stekl,J. Tebrügge,R. Temminghoff,R. Theinert,J. Timm,T. Wester,B. Wonsak,S. Zatschler,K. Zuber
Physics , 2015, DOI: 10.1016/j.nima.2015.10.079
Abstract: The COBRA demonstrator, a prototype for a large-scale experiment searching for neutrinoless double beta-decay, was built at the underground laboratory Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It consists of an array of 64 monolithic, calorimetric CdZnTe semiconductor detectors with a coplanar-grid design and a total mass of 380g. It is used to investigate the experimental challenges faced when operating CdZnTe detectors in low-background mode, to identify potential background sources and to show the long-term stability of the detectors. The first data-taking period started in 2011 with a subset of the detectors, while the demonstrator was completed in November 2013. To date, more than 250kg d of data have been collected. This paper describes technical details of the experimental setup and the hardware components.
Study of Cosmogenic Neutron Backgrounds at LNGS  [PDF]
A. Empl,R. Jasim,E. Hungerford,P. Mosteiro
Physics , 2012,
Abstract: Cosmic muon interactions are important contributors to backgrounds in underground detectors when searching for rare events. Typically neutrons dominate this background as they are particularly difficult to shield and detect in a veto system. Since actual background data is sparse and not well documented, simulation studies must be used to design shields and predict background rates. This means that validation of any simulation code is necessary to assure reliable results. This work studies the validation of the FLUKA simulation code, and reports the results of a simulation of cosmogenic background for a liquid argon two-phase detector embedded within a water tank and liquid scintillator shielding.
An injector for the CLIC test Facility (CTF3)  [PDF]
L. Rinolfi,H. Braun,R. Pittin,F. Zhou,B. Mouton,R. Miller,D. Yeremian
Physics , 2000,
Abstract: The CLIC Test Facility (CTF3) is an intermediate step to demonstrate the technical feasibility of the key concepts of the new RF power source for CLIC. CTF3 will use electron beams with an energy range adjustable from 170 MeV (3.5 A) to 380 MeV (with low current). The injector is based on a thermionic gun followed by a classical bunching system embedded in a long solenoidal field. As an alternative, an RF photo-injector is also being studied. The beam dynamics studies on how to reach the stringent beam parameters at the exit of the injector are presented. Simulations performed with the EGUN code showed that a current of 7 A can be obtained with an emittance less than 10 mm.mrad at the gun exit. PARMELA results are presented and compared to the requested beam performance at the injector exit. Sub-Harmonic Bunchers (SHB) are foreseen, to switch the phase of the bunch trains by 180 degrees from even to odd RF buckets. Specific issues of the thermionic gun and of the SHB with fast phase switch are discussed.
Radioactive contamination of BaF2 crystal scintillator  [PDF]
O. G. Polischuk,P. Belli,R. Bernabei,F. Cappella,V. Caracciolo,R. Cerulli,A. Di Marco,F. A. Danevich,A. Incicchitti,D. V. Poda,V. I. Tretyak
Statistics , 2013,
Abstract: Barium fluoride (BaF$_2$) crystal scintillators are promising detectors to search for double beta decay processes in $^{130}$Ba ($Q_{2{\beta}}$ = 2619(3) keV) and $^{132}$Ba ($Q_{2{\beta}}$ = 844(1) keV). The $^{130}$Ba isotope is of particular interest because of the indications on 2${\beta}$ decay found in two geochemical experiments. The radioactive contamination of BaF$_2$ scintillation crystal with mass of 1.714 kg was measured over 113.4 hours in a low-background DAMA/R&D set-up deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (LNGS, Italy). The half-life of $^{212}$Po (present in the crystal scintillator due to contamination by radium) was estimated as $T_{1/2}$ = 298.8 $\pm$ 0.8(stat.) $\pm$ 1.4(syst.) ns by analysis of the events pulse profiles.
Searches for neutrinoless resonant double electron captures at LNGS  [PDF]
P. Belli,R. Bernabei,R. S. Boiko,V. B. Brudanin,F. Cappella,V. Caracciolo,R. Cerulli,D. M. Chernyak,F. A. Danevich,S. d'Angelo,A. Di Marco,M. L. Di Vacri,E. N. Galashov,A. Incicchitti,V. V. Kobychev,G. P. Kovtun,N. G. Kovtun,V. M. Mokina,M. Laubenstein,S. S. Nagorny,S. Nisi,D. V. Poda,R. B. Podviyanuk,O. G. Polischuk,D. Prosperi,A. P. Shcherban,V. N. Shlegel,D. A. Solopikhin,Yu. G. Stenin,J. Suhonen,A. V. Tolmachev,V. I. Tretyak,Ya. V. Vasiliev,R. P. Yavetskiy
Physics , 2012, DOI: 10.1088/1742-6596/375/1/042024
Abstract: Several experiments were performed during last years at underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (LNGS) of the INFN (Italy) to search for resonant 2$\varepsilon0\nu$ captures in 96Ru, 106Cd, 136Ce, 156Dy, 158Dy, 180W, 184Os, 190Pt with the help of HP Ge semiconductor detectors, and ZnWO4 and 106CdWO4 crystal scintillators. No evidence for r-2$\varepsilon0\nu$ decays was found, and only T_{1/2} limits were established in the range of 10^{14}-10^{21} yr.
Liquid scintillator production for the NOvA experiment  [PDF]
S. Mufson,B. Baugh,C. Bower,T. E. Coan,J. Cooper,L. Corwin,J. A. Karty,P. Mason,M. D. Messier,A. Pla-Dalmau,M. Proudfoot
Physics , 2015, DOI: 10.1016/j.nima.2015.07.026
Abstract: The NOvA collaboration blended and delivered 8.8 kt (2.72M gal) of liquid scintillator as the active detector medium to its near and far detectors. The composition of this scintillator was specifically developed to satisfy NOvA's performance requirements. A rigorous set of quality control procedures was put in place to verify that the incoming components and the blended scintillator met these requirements. The scintillator was blended commercially in Hammond, IN. The scintillator was shipped to the NOvA detectors using dedicated stainless steel tanker trailers cleaned to food grade.
Beam Dynamics Simulation for the CTF3 Drive-Beam Accelerator  [PDF]
D. Schulte
Physics , 2000,
Abstract: A new CLIC Test Facility (CTF3) at CERN will serve to study the drive beam generation for the Compact Linear Collider (CLIC). CTF3 has to accelerate a 3.5 A electron beam in almost fully-loaded structures. The pulse contains more than 2000 bunches, one in every second RF bucket, and has a length of more than one microsecond. Different options for the lattice of the drive-beam accelerator are presented, based on FODO-cells and triplets as well as solenoids. The transverse stability is simulated, including the effects of beam jitter, alignment and beam-based correction.
Coexistence of 'alpha+ 208Pb' cluster structures and single-particle excitations in 212Po  [PDF]
A. Astier,P. Petkov,M. -G. Porquet,D. S. Delion,P. Schuck
Physics , 2010, DOI: 10.1140/epja/i2010-11053-6
Abstract: Excited states in 212Po have been populated by alpha transfer using the 208Pb(18O,14C) reaction at 85MeV beam energy and studied with the EUROBALL IV gamma multidetector array. The level scheme has been extended up to ~ 3.2 MeV excitation energy from the triple gamma coincidence data. Spin and parity values of most of the observed states have been assigned from the gamma angular distributions and gamma -gamma angular correlations. Several gamma lines with E(gamma) < 1 MeV have been found to be shifted by the Doppler effect, allowing for the measurements of the associated lifetimes by the DSAM method. The values, found in the range [0.1-0.6] ps, lead to very enhanced E1 transitions. All the emitting states, which have non-natural parity values, are discussed in terms of alpha-208Pb structure. They are in the same excitation-energy range as the states issued from shell-model configurations.
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