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NEXT Collaboration,
V. Álvarez, M. Ball,
F. I. G. M. Borges,
S. Cárcel,
J. M. Carmona,
J. Castel,
J. M. Catalá,
S. Cebrián,
A. Cervera, [......],
J. Torrent,
Z. Tsamalaidze,
D. Vázquez,
E. Velicheva,
J. F. C. A. Veloso,
J. A. Villar,
R. C. Webb,
T. Weber,
J. White,
N. Yahlali
[show abstract]
[hide abstract]
ABSTRACT: NEXT-100 experiment aims at searching the neutrinoless double-beta decay of
the Xe-136 isotope using a TPC filled with a 100 kg of high-pressure gaseous
xenon, with 90% isotopic enrichment. The experiment will take place at the
Laboratorio Subterr\'aneo de Canfranc (LSC), Spain. NEXT-100 uses
electroluminescence (EL) technology for energy measurement with a resolution
better than 1% FWHM. The gaseous xenon in the TPC additionally allows the
tracks of the two beta particles to be recorded, which are expected to have a
length of up to 30 cm at 10 bar pressure. The ability to record the topological
signature of the neutrinoless double-beta events provides a powerful background
rejection factor for the double-beta experiment.
In this paper, we present a novel 3D imaging concept using SiPMs coated with
tetraphenyl butadiene (TPB) for the EL read out and its first implementation in
NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment. The design and
the first characterization measurements of the NEXT-DEMO SiPM tracking system
are presented. The SiPM response uniformity over the tracking plane drawn from
its gain map is shown to be better than 4%. An automated active control system
for the stabilization of the SiPMs gain was developed, based on the voltage
supply compensation of the gain drifts. The gain is shown to be stabilized
within 0.2% relative variation around its nominal value, provided by Hamamatsu,
in a temperature range of 10 degree C. The noise level from the electronics and
the SiPM dark noise is shown to lay typically below the level of 10
photoelectrons (pe) in the ADC. Hence, a detection threshold at 10 pe is set
for the acquisition of the tracking signals. The ADC full dynamic range (4096
channels) is shown to be adequate for signal levels of up to 200
pe/microsecond, which enables recording most of the tracking signals.
06/2012;
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E. Go ́mez,
R.M. Gutie ́rrez,
M. Losada,
G. Navarro,
A.L. Ferreira,
C.A.B. Oliveira,
J.F.C.A. Veloso,
D. Chan,
A. Goldschmidt,
D. Hogan, [......],
S. Cebria ́n,
T. Dafni,
H. Go ́mez,
D.C. Herrera,
I.G. Irastorza,
G. Luzo ́n,
A. Rodr ́ıguez,
L. Segu ́ı,
A. Toma ́s,
J.A. Villar
[show abstract]
[hide abstract]
ABSTRACT: We propose an EASY (Electroluminescent ApparatuS of high Yield) and SOFT (Separated Optimized FuncTion) time-projection chamber for the NEXT experiment, that will search for neutrinoless double beta decay (ββ0ν) in 136 Xe. Our experiment must be competitive with the new generation of ββ0ν searches already in operation or in construction. This requires a detector with very good energy resolution (1%), very low background con-tamination (∼ 10 −4 counts/(keV · kg · y)) and large target mass. In addition, it needs to be operational as soon as possible. The design described here optimizes energy resolution thanks to the use of proportional electroluminescent amplification (EL), which provides a large yield of photons as a signal; it is compact, as the Xe gas is under high pressure; and it allows the measurement of the topological signature of the event to further reduce the background contamination. The SOFT design uses different sensors for tracking and calorimetry. We propose the use of SiPMs (MPPCs) coated with a suitable wavelength shifter for the tracking, and the use of radiopure photomultipliers for the measurement of the energy and the primary scintillation needed to estimate the t 0 . This design provides the best possible energy resolution compared with other NEXT designs based on avalanche gain devices. The baseline design is an Asymmetric Neutrino Gas EL apparatus (ANGEL), which was already outlined in the NEXT LOI. ANGEL is conceived to be easy to fabricate. It requires very little R&D and most of the proposed solutions have already been tested in the NEXT-1 prototypes. Therefore, the detector can be ready by 2013. The detector may be upgraded to a fiducial mass of 1 ton after the initial physics runs, following the successful approach of GERDA and XENON experiments. With our design, NEXT will be competitive and possibly out-perform existing proposals for next-generation neutrinoless double-beta decay experiments. In this Conceptual Design Report (CDR) we discuss first the physics case, present a full design of the detector, describe the NEXT-1 EL prototypes and their initial results, and outline a project to build a detector with 100 kg of enriched xenon to be installed in the Canfranc Underground Laboratory in 2013.
Journal of Instrumentation 06/2012; 7(T06001). · 1.87 Impact Factor
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V Álvarez,
J Agramunt, M Ball,
M Batallé,
J Bayarri,
F I G Borges,
H Bolink,
H Brine,
S Cárcel,
J M Carmona, [......],
A Tomás,
Z Tsamalaidze,
D Vázquez,
E Velicheva,
J F C A Veloso,
J A Villar,
R Webb,
T Weber,
J T White,
N Yahlali
[show abstract]
[hide abstract]
ABSTRACT: Silicon photomultipliers (SiPM) are the photon detectors chosen for the tracking readout in NEXT, a neutrinoless \bb decay experiment which uses a high pressure gaseous xenon time projection chamber (TPC). The reconstruction of event track and topology in this gaseous detector is a key handle for background rejection. Among the commercially available sensors that can be used for tracking, SiPMs offer important advantages, mainly high gain, ruggedness, cost-effectiveness and radio-purity. Their main drawback, however, is their non sensitivity in the emission spectrum of the xenon scintillation (peak at 175 nm). This is overcome by coating these sensors with the organic wavelength shifter tetraphenyl butadiene (TPB). In this paper we describe the protocol developed for coating the SiPMs with TPB and the measurements performed for characterizing the coatings as well as the performance of the coated sensors in the UV-VUV range.
Journal of Instrumentation 02/2012; 7(02):P02010. · 1.87 Impact Factor
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NEXT Collaboration,
V. Álvarez, M. Ball,
M. Batallé,
J. Bayarri,
F. I. G. Borges,
S. Cárcel,
J. M. Carmona,
J. Castel,
J. M. Catalá, [......],
A. Tomás,
Z. Tsamalaidze,
D Vázquez,
E. Velicheva,
J.F.C.A. Veloso,
J. A. Villar,
R Webb,
T. Weber,
J White,
N. Yahlali
[show abstract]
[hide abstract]
ABSTRACT: We propose an EASY (Electroluminescent ApparatuS of high Yield) and SOFT
(Separated Optimized FuncTion) time-projection chamber for the NEXT experiment,
that will search for neutrinoless double beta decay (bb0nu) in Xe-136. Our
experiment must be competitive with the new generation of bb0nu searches
already in operation or in construction. This requires a detector with very
good energy resolution (<1%), very low background con- tamination (1E-4
counts/(keV \bullet kg \bullet y)) and large target mass. In addition, it needs
to be operational as soon as possible. The design described here optimizes
energy resolution thanks to the use of proportional electroluminescent
amplification (EL); it is compact, as the Xe gas is under high pressure; and it
allows the measurement of the topological signature of the event to further
reduce the background contamination. The SOFT design uses different sensors for
tracking and calorimetry. We propose the use of SiPMs (MPPCs) coated with a
suitable wavelength shifter for the tracking, and the use of radiopure
photomultipliers for the measurement of the energy and the primary
scintillation needed to estimate the t0. This design provides the best possible
energy resolution compared with other NEXT designs based on avalanche gain
devices. The baseline design is an Asymmetric Neutrino Gas EL apparatus
(ANGEL), which was already outlined in the NEXT LOI. ANGEL is conceived to be
easy to fabricate. It requires very little R&D and most of the proposed
solutions have already been tested in the NEXT-1 prototypes. Therefore, the
detector can be ready by 2013. In this Conceptual Design Report (CDR) we
discuss first the physics case, present a full design of the detector, describe
the NEXT-1 EL prototypes and their initial results, and outline a project to
build a detector with 100 kg of enriched xenon to be installed in the Canfranc
Underground Laboratory in 2013.
06/2011;
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[show abstract]
[hide abstract]
ABSTRACT: NEXT is a new experiment to search for neutrinoless double beta decay using a 100 kg radio-pure high-pressure gaseous xenon TPC. The detector requires excellent energy resolution, which can be achieved in a Xe TPC with electroluminescence readout. Hamamatsu R8520-06SEL photomultipliers are good candidates for the scintillation readout. The performance of this photomultiplier, used as VUV photosensor in a gas proportional scintillation counter, was investigated. Initial results for the detection of primary and secondary scintillation produced as a result of the interaction of 5.9 keV X-rays in gaseous xenon, at room temperature and at pressures up to 3 bar, are presented. An energy resolution of 8.0% was obtained for secondary scintillation produced by 5.9 keV X-rays. No significant variation of the primary scintillation was observed for different pressures (1, 2 and 3 bar) and for electric fields up to 0.8 V cm-1 torr-1 in the drift region, demonstrating negligible recombination luminescence. A primary scintillation yield of 81 \pm 7 photons was obtained for 5.9 keV X-rays, corresponding to a mean energy of 72 \pm 6 eV to produce a primary scintillation photon in xenon. Comment: 16 pages, 10 figures, accepted for publication in JINST
09/2010;
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[show abstract]
[hide abstract]
ABSTRACT: Autonomy of embedded agents in intelligent environments is highly debated topic; while some believe that agents should have very minimal autonomy and should only act as directly instructed by the user, others consider providing agents with autonomy to be an essential aspect to building intelligent environments. This paper reports on the current progress of our project to enable human users and agents to collaborate in managing intelligent environments as a team. We seek to develop an adjustable-autonomy agent in an effort to explore user acceptance of pervasive computing and the use of autonomous agents therein, as wells as aiming to improve the robustness and reliability of future intelligent environment systems. We present our Adjustable-autonomy Behaviour-Based Agent (ABBA) architecture model and discuss our initial trials with our prototype system, built on a smart home emulator, which demonstrate the plausibility of employing adjustable-autonomy in full-scale intelligent environments and pervasive computing systems.
Intelligent Environments (IE), 2010 Sixth International Conference on; 08/2010
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[show abstract]
[hide abstract]
ABSTRACT: The search of the neutrinoless double-β decay address the major Physics goals of revealing the nature of the neutrino and setting an absolute scale for its mass. The observation of a positive ββ0ν signal, the unique signature of Majorana neutrinos, would have deep consequences in particle physics and cosmology. Therefore, any claim of observing a positive signal shall require extremely robust evidences. NEXT is a new double-β experiment which aims at building a 100 kg high pressure Xe136 gas TPC, to be hosted in the Canfranc Underground Laboratory (LSC), in Spain. This paper address the novel design concept of NEXT TPC believed to provide a pathway for an optimized and robust double-β experiment.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2010; 617(1-3):520-522. · 1.21 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: Pervasive intelligent environments, such as digital homes, offer huge potentials for eHealth services. However, there is a question as to how best to manage (i.e. configure and program) these systems. The majority of solutions to-date rely exclusively on either end users or autonomous agents to manage the environment, which may not be suitable for all users and in certain situations, especially in eHealth applications where uses may have very specific requirements that can change considerably over time. In this work-in-progress paper we argue that human-agent teamwork is vital for the adoption of future pervasive computing systems into our everyday lives; we discuss these issues, exposing the problem of exclusive management and we explore a solution, presenting our novel architecture for an adjustable autonomy agent that enables human-agent based teamwork. This work contributes to the PAL project: a collaborative research effort between University of Essex, BT, University of Cambridge and Ericsson.
Pervasive Computing Technologies for Healthcare (PervasiveHealth), 2010 4th International Conference on-NO PERMISSIONS; 04/2010
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J Díaz,
N Yahlali, M Ball,
J A S Barata,
F I G M Borges,
E Calvo,
S Cárcel,
J M Carmona,
S Cebrián,
A Cervera, [......],
J Ruz,
N F Sánchez,
F P Santos,
J M F Dos Santos,
L Serra,
M Sorel,
L M N Távora,
A Tomás,
J F C A Veloso,
A Verdugo
[show abstract]
[hide abstract]
ABSTRACT: Neutrinoless double beta decay measurements are the most promising experiments both to reveal the Majorana nature of the neutrino and to set a value for its mass. The NEXT project propose to build a High pressure Xenon TPC in the Canfranc Underground Laboratory (Huesca, Spain) to measure double-beta decay of 136Xe, both normal and neutrinoless, with a source mass of 100 kg of enriched xenon.
Journal of Physics Conference Series 07/2009; 179(1):012005.
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The NEXT Collaboration,
F. Granena,
T Lux,
F. Nova,
J. Rico,
F. Sanchez,
D. R. Nygren,
J.A.S. Barata,
F.I.G.M. Borges,
C.A.N. Conde, [......],
J. Galan,
H. Gomez,
F. J. Iguaz,
I. G. Irastorza,
G. Luzon,
J Morales,
A Rodriguez,
J. Ruz,
A. Tomas,
J. A. Villar
[show abstract]
[hide abstract]
ABSTRACT: We propose a novel detection concept for neutrinoless double-beta decay searches. This concept is based on a Time Projection Chamber (TPC) filled with high-pressure gaseous xenon, and with separated-function capabilities for calorimetry and tracking. Thanks to its excellent energy resolution, together with its powerful background rejection provided by the distinct double-beta decay topological signature, the design discussed in this Letter Of Intent promises to be competitive and possibly out-perform existing proposals for next-generation neutrinoless double-beta decay experiments. We discuss the detection principles, design specifications, physics potential and R&D plans to construct a detector with 100 kg fiducial mass in the double-beta decay emitting isotope Xe(136), to be installed in the Canfranc Underground Laboratory. Comment: Letter of Intent to the LSC Scientific Committee 115 pages
07/2009;
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[show abstract]
[hide abstract]
ABSTRACT: We describe a technology for creating easy-to- manufacture combined function magnets. The field is produced by double-helix coils in which the axial path of the windings is defined by a sinusoidal function containing the superposition of the desired multipoles. The result is a magnet that can contain, for example, a pure dipole field with superimposed multipole fields whose magnitude relative to the dipole field can be easily controlled to any level. We show how low level (i.e. 0.1%-1%) modulation amplitudes of the superimposed multipoles can be used as built-in or "free" correction coils to compensate for iron saturation effects or geometrically-induced multipoles. The combined function winding can also be used to superimpose a dipole and quadrupole winding where the quadrupole integral of Gdl can be adjusted to any level desired over the length of the main dipole magnet. In this way a "free" quadrupole can be obtained within a dipole. The characteristics of this type of combined function magnet are also discussed.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: The Low Energy Neutron Source (LENS) at Indiana University is producing neutrons by using a 7 MeV proton beam incident on a Beryllium target. The Proton Delivery System is currently being upgraded [1], [2]. A new AccSys Technology,Inc. DTL section [3] will be added to increase proton beam energy from 7 to 13 MeV. A 3 MeV RFQ and 10 MeV DTL will be powered by two 1.25 MW klystrons. The goal of this upgrade is a 13 MeV,25 mA proton beam with duty factor greater than 3%. At this power level it becomes increasingly important to make a proton beam that is uniformly distributed to prevent excessive thermal stress at the surface of the Be- target. To achieve this goal two octupole magnets are being implemented in each LENS beam transport line. In this paper we discuss the experimental results of the beam intensity redistribution as well as some features inherent in tuning of the nonlinear beamline and our operational experience.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: The Indiana University Cyclotron Facility is operating a low energy neutron source which provides cold neutrons for material research and neutron physics as well as neutrons in the MeV energy range for the neutron radiation effects studies. Neutrons are being produced by a 7 MeV proton beam incident on a beryllium target. Since the first commissioning of the LENS Proton Delivery System (PDS) in December 2004 its performance has been significantly improved. The RF system of the accelerator has been upgraded by replacing 350 kW 425 MHz 12 tube amplifiers with two Litton 5773 klystron RF tubes capable of running at 425 MHz and 1.25 MW. Since the commissioning of the klystrons, a proton current of 25 mA at 7 MeV and 0.6% duty factor has been successfully delivered to the beryllium target. A future part of this upgrade will introduce a new 6 MeV DTL section to increase proton beam energy from 7 to 13 MeV. The 3 MeV RFQ and 4 MeV DTL will be powered by one klystron and the 6 MeV DTL will be powered by the second klystron. The expected output is 25 mA and 13 MeV of proton current at 0.6% duty factor. A second target station has been added to allow separate source optimization for the two primary research programs (cold neutrons and radiation effects). Other upgrades include increasing the RF duty factor to 3% through the installation of a new power supply for the klystrons. In this contribution we discuss the results of the commissioning of the new RF system, second beamline and second target station, as well as improvement in the beam parameters after these upgrades. The future plans will also be outlined.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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C. Drennan, M. Ball,
A.R. Franck,
D.J. Harding,
P.A. Kasley,
G.E. Krafczyk,
M.J. Kucera,
J. Lackey,
D. McArthur,
J. Misek,
W. Pellico,
E.J. Prebys,
K. Triplett,
D.A. Wolff
[show abstract]
[hide abstract]
ABSTRACT: To better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron, a new package of six corrector elements has been designed, incorporating both normal and skew orientations of dipole, quadrupole, and sextupole magnets. The devices are under construction and will be installed in 48 locations in the Booster accelerator. Each of these 288 corrector magnets will be individually powered. Each of the magnets will be individually controlled using operator programmed current ramps designed specifically for each type of Booster acceleration cycle. This paper provides an overview of the corrector magnet installation in the accelerator enclosure, power and sensor interconnections, specifications for the switch-mode power supplies, rack and equipment layouts, controls and interlock electronics, and the features of the operator interface for programming the current ramps and adjusting the timing of the system triggers.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
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[show abstract]
[hide abstract]
ABSTRACT: An extensive survey is being conduc Methods of preparing suitable samples are described, and results of low temperature microwave resonance experiments with Yb(3+), Dy(3+), Er(3+), and Nd(3+) ions are given. For each of these ions, the ground state is a doublet which can be characterized by three principal values of a g tensor, and with one exception, all the principal values have been determined for these ions in both yttrium aluminium and yttrium gallium garnet. The local environment of the rareearth ions is far from being spherically or cubically symmetrical, so that the individual rare earth ions have magnetic properties which are very anisotropic. The relation of these results to the observed anisotropies in rare earth iron garnets and rare earth doped YIG are discussed. AD-265 20 Div. 25, 17 (TIPSM/BRW) OTS price $4.60 Ordnance Materials Research Office, Watertown, Mass. HIGH LOADING RATES IN ETALS, by R. Beeuwkes, Jr. June 59, 42p. incl. illus. (MRL rep. o. Proj. TB 4-001 and DA 5-93-32-001) Unclassified repot DESCRIPTORS: (*Mechanics, *Metals, Alloys, Ordnance steel, Gun barrels, Load distribution, Velocity, Plasticity, Deformation,tresses, Mechanical properties, Tensile properties, Fracture (Mechanis, g (Mechanics), Impact shock, Hardness, Terminal ballisic,test methods, Tests, Analysis.) Photoelastic materials. High loading rate effects are found to commonly occur in both low and high speed apparatus nd tess. Though commonly disregarded, it is important to understand these effects as shown by examples which also indicate how low speed tests may oftn b satisfactorily substituted for high speed tests. The severity of rates, judged by materials behavior which is considered the outstanding criterion, is found to be crucially dependent on temperature. (Author)
04/1961;
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[show abstract]
[hide abstract]
ABSTRACT: Low-temperature magnetic susceptibility measurements have been carried out on single crystals of Dy <sub>3</sub> Al <sub>5</sub> O <sub>12</sub> , Dy <sub>3</sub> Ga <sub>5</sub> O <sub>12</sub> , Er <sub>3</sub> Al <sub>5</sub> O <sub>12</sub> , Er <sub>3</sub> Ga <sub>5</sub> O <sub>12</sub> , and diamagnetic Y <sub>3</sub> Al <sub>5</sub> O <sub>12</sub> and Y <sub>3</sub> Ga <sub>5</sub> O <sub>12</sub> containing nominally 1% Dy and Er. The dilute samples have also been investigated by paramagnetic resonance (9 kMc at 4.2°K), and with the exception of Dy in Y <sub>3</sub> Al <sub>5</sub> O <sub>12</sub> for which no resonance was found, the g tensors of the ground state doublets have been determined in each case. A wide range of principal g values was found (1 to 11) and considerable differences between corresponding Al and Ga compounds were observed. These results show that the electronic ground states of the Dy <sup>3+</sup> and Er <sup>3+</sup> ions are in general very anisotropic in these structures, and that their magnetic properties are very sensitive to small changes of environment. The susceptibility measurements also indicated the presence of low-lying crystal field states, and a weak, but rather complex, interaction between the rare-earth ions. In the case of Dy <sub>3</sub> Al <sub>5</sub> O <sub>12</sub> the interactions lead to antiferromagnetic ordering at 2.5°K. Difficultie-
s in applying these results to the interpretation of the properties of ferrimagnetic garnets containing Dy and Er are discussed.
Journal of Applied Physics 04/1961; · 2.17 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The Low Energy Neutron Source (LENS) at Indiana University is producing neutrons by using a 7 MeV proton beam incident on a Beryllium target. The Proton Delivery System is currently being upgraded [1], [2]. A new AccSys Technology, Inc. DTL section [3] will be added to increase proton beam energy from 7 to 13 MeV. A 3 MeV RFQ and 10 MeV DTL will be powered by two 1.25 MW klystrons. The goal of this upgrade is a 13 MeV, 25 mA proton beam with duty factor greater than 3%. At this power level it becomes increasingly important to make a proton beam that is uniformly distributed to prevent excessive thermal stress at the surface of the Be-target. To achieve this goal two octupole magnets are being implemented in each LENS beam transport line. In this paper we discuss the experimental results of the beam intensity redistribution as well as some features inherent in tuning of the nonlinear beamline and our operational experience.
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[show abstract]
[hide abstract]
ABSTRACT: The search for neutrinoless double beta decay (0νββ) is an important topic in contemporary physics with many active experiments. New projects are planning to use high-pressure xenon gas as both source and detection medium. The secondary scintillation processes available in noble gases permit large amplification with negligible statistical fluctuations, offering the prospect of energy resolution approaching the Fano factor limit. This Letter reports results for xenon secondary scintillation yield, at room temperature, as a function of electric field in the gas scintillation gap for pressures ranging from 2 to 10 bar. A Large Area Avalanche Photodiode (LAAPD) collected the VUV secondary scintillation produced in the gas. X-rays directly absorbed in the LAAPD are used as a reference for determining the number of charge carriers produced by the scintillation pulse and, hence, the number of photons impinging the LAAPD. The number of photons produced per drifting electron and per kilovolt, the so-called scintillation amplification parameter, displays a small increase with pressure, ranging from 141±6 at 2 bar to 170±10 at 8 bar. In our setup, this parameter does not increase above 8 bar due to non-negligible electron attachment. The results are in good agreement with those presented in the literature in the 1 to 3 bar range. The increase of the scintillation amplification parameter with pressure for high gas densities has been also observed in former work at cryogenic temperatures.
Physics Letters B.
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Thorsten Lux,
F Granena,
F Nova,
J Rico,
D R Nygren,
J A S Barata,
F I G M Borges,
C A N Conde,
T H V T Dias,
L M P Fernandes, [......],
J Galan,
H Gomez,
F J Iguaz,
I G Irastorza,
G Luzon,
J Morales,
A Rodriguez,
J Ruz,
A Tomas,
J A Villar
