Search

Cadmium-116 is one of the favorable candidates for neutrinoless double-beta decay ( 0 ν β β ) searches from both theoretical and experimental points of view, in particular thanks to the high energy of the decay (2813.49 keV), the possibility of the industrial enrichment in 116 Cd and its use in the well-established production of cadmium tungstate crystal scintillators. In this work, we present low-temperature tests of two 0.6 kg 116 CdWO 4 crystals enriched in 116 Cd to 82 % as scintillating bolometers. These detectors were operated underground, with one at the Laboratoire Souterrain de Modane (LSM) in France and the second at the Laboratorio Subterraneo de Canfranc (LSC) in Spain. The two crystals are coupled to bolometric Ge light detectors in order to register the scintillation light. The double readout of heat and scintillation enables reduction in the background in the region of interest by discriminating between different populations of particles. The main goal of these tests is the study of the crystals' radiopurity and the detectors' performance. The achieved results are extremely promising, in particular, the detectors demonstrate a high energy resolution (11–16 keV FWHM at 2615 keV) and a high-efficiency discrimination of the alpha background ( ∼ 20 σ ). These results, achieved for the first time with large mass enriched 116 CdWO 4 crystals, demonstrate prospects of the bolometric technology for high-sensitivity searches of 116 Cd 0 ν β β decay. [ABSTRACT FROM AUTHOR]

Abstract: The ATLAS Tile Calorimeter is a sampling detector composed by cells made of iron-scintillator tiles. The calorimeter cell signals are digitized in the front-end electronics and transmitted to the Read-Out Drivers (RODs) at the first level trigger rate. The ROD receives triggered data from up to 9856 channels and provides the energy, phase and quality factor of the signals to the second level trigger. The back-end electronics is divided into four partitions containing eight RODs each. Therefore, a total of 32 RODs are used to process and transmit the data of the TileCal detector. In order to emulate the detector signals in the production and commissioning of ROD modules a board called ROD Injector and Multiplexer Board (RIMBO) was designed. In this paper, the RIMBO main functional blocks, PCB design and the different operation modes are described. It is described the crucial role of the board within the TileCal ROD test-bench in order to emulate the front-end electronics during the validation of ROD boards as well as during the evaluation of the ROD signal reconstruction algorithms. Finally, qualification and performance results for the injection operation mode obtained during the Tile Calorimeter ROD production tests are presented. [ABSTRACT FROM AUTHOR]

Abstract: The calorimeter system of the LHCb experiment consists of a scintillator layer (SPD), a preshower detector (PS), an electromagnetic calorimeter (ECAL) and a hadronic calorimeter (HCAL), and allows to trigger on hadron, electron and photon candidates. The time synchronization of the four sub-detectors studied with cosmic rays, LHC beam injection tests and LHC proton proton collisions is presented. Energy calibration methods for each subsystem are discussed as well. [ABSTRACT FROM AUTHOR]

The application of a CAEN DT5730 digitizer unit for fast neutron metrology is explored. Measurements were made at the Accelerator for Metrology and Neutron Applications in External Dosimetry (AMANDE) monoenergetic neutron facility of the IRSN, France, over a neutron energy range from 1.2 to 7.0 MeV using a BC501A scintillator. The DT5730 digitizer and an analog system based on NIM electronics and an MPA-3 multichannel analyzer acquisition unit were used, under identical beam conditions, for data acquisition. Several observables were compared between the two systems including the quality of pulse shape discrimination (PSD), neutron energy distribution derived from unfolding analyses, and deadtime effects over a range of beam currents from 0.1 to $5.1~\mu \text{A}$. The suitability of the digital system for fast neutron metrology measurements both in the laboratory and in workplace fields is discussed. [ABSTRACT FROM AUTHOR]

We exploited the potential of radiation-induced emissions (RIEs) in the visible domain of a nitrogen-doped, silica-based, multimode optical fiber to monitor the very high dose rates associated with experiments at different pulsed X-ray facilities. We also tested this sensor at lower dose rates associated with steady-state X-ray irradiation machines (up to 100 keV photon energy, mean energy of 40 keV). For transient exposures, dedicated experimental campaigns were performed at ELSA (Electron et Laser, Source X et Applications) and ASTERIX facilities from CEA (Commissariat à l'Energie Atomique—France) to characterize the RIE of this fiber when exposed to X-ray pulses with durations of a few µs or ns. These facilities provide very large dose rates: in the order of MGy(SiO2)/s for the ELSA facility (up to 19 MeV photon energy) and GGy(SiO2)/s for the ASTERIX facility (up to 1 MeV). In both cases, the RIE intensities, mostly explained by the fiber radioluminescence (RIL) around 550 nm, with a contribution from Cerenkov at higher fluxes, linearly depend on the dose rates normalized to the pulse duration delivered by the facilities. By comparing these high dose rate results and those acquired under low-dose rate steady-state X-rays (only RIL was present), we showed that the RIE of this multimode optical fiber linearly depends on the dose rate over an ultra-wide dose rate range from 10−2 Gy(SiO2)/s to a few 109 Gy(SiO2)/s and photons with energy in the range from 40 keV to 19 MeV. These results demonstrate the high potential of this class of radiation monitors for beam monitoring at very high dose rates in a very large variety of facilities as future FLASH therapy facilities. [ABSTRACT FROM AUTHOR]

The main goal of the NEMO-3 experiment is to search for neutrinoless double-beta decay and thus to investigate physics beyond the Standard Model. The expected sensitivity for the effective Majorana neutrino mass is on the order of 0.1 eV. The NEMO-3 detector has been completely installed in the Modane Underground Laboratory (LSM), France, and has been taking data since February 2003. In this paper, a brief description of the NEMO-3 detector and some performances of the initial runs are presented. The first preliminary results for both two-neutrino (2β2ν) and neutrinoless double-beta decay (2β0ν) of 100Mo, 82Se, 116Cd, and 150Nd are given.© 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Coherent elastic neutrino–nucleus scattering ( CE ν NS ) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study CE ν NS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring CE ν NS of reactor anti-neutrinos. A new experimental site, the Very-Near-Site (VNS), at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 GW th reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. Furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the physics potential of NUCLEUS at the Chooz nuclear power plant. [ABSTRACT FROM AUTHOR]

Muography is a relatively new geophysical imaging method that uses muons to provide estimates of average densities along particular lines of sight. Muography can only see above the horizontal elevation of the detector and it is therefore attractive to attempt a joint inversion of muography data with gravity data, which is also responsive to density but generally requires combination with another geophysical data set to overcome issues related to non-uniqueness and poor depth resolution. Some previous work has investigated this joint inverse problem and demonstrated the potential improvements to be gained by jointly inverting muography and gravity data. However, there has yet to be a thorough investigation of different numerical approaches for formulating the joint inverse problem. Particularly important is how to account for the fact that even though the two data types are sensitive to the same physical quantity, density, they respond through different response functions. Moreover, the two measurements are affected by different systematic uncertainties that are difficult to model. In this work, we considered an approximation where the two density quantities, inferred from the two data types, can be related by an unknown scalar offset. We considered various existing and new joint inversion methods that might solve this problem and we applied them to a synthetic volcano imaging scenario based on the Puy de Dôme volcano in the Central Massif region of France. We used unstructured meshes in our modelling to adequately honour the significant topography in that scenario. Our experiments indicated that the most successful joint inversion method for this type of geological scenario was one in which the data misfit function is reformulated to automatically determine the best-fitting offset following a least-squares minimization argument. However, other approaches showed merit and we suggest several of the investigated methods be applied and compared for any specific joint inversion scenario. [ABSTRACT FROM AUTHOR]

The phenomenology of multi-particle production of hadrons is reviewed, with emphasis on the results at the Large Hadron Collider (LHC): the first part of the review focuses on the basic kinematic measurements of charged tracks and identified hadrons in minimum bias interactions; the second part reports the short- and long-range correlation studies; the third part concentrates on the underlying event phenomenology in different final states; the fourth part, which constitutes a bottom line on the phenomenology of multiple parton interactions, considers the consequences of multiple hard-scatterings in a single hadron-hadron collisions. Some relevant highlights from the heavy ion program are also discussed. [ABSTRACT FROM AUTHOR]

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of $\sqrt{s} = 900~\mbox{GeV}$ and 7 TeV collected during 2009 and 2010. Then, using the decay of K and ? particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5 % for central isolated hadrons and 1-3 % for the final calorimeter jet energy scale. [ABSTRACT FROM AUTHOR]

In recent years the Tevatron Run-II collaborations have extended the search for Higgs bosons which was pioneered during the LEP accelerator operation between 1989 and 2000. This review concisely discusses the experimental constraints set by the CDF and DØ collaborations with the complete dataset taken up to September 2011. Model-independent and model-dependent limits on Higgs boson masses and couplings have been set and interpretations are discussed both in the context of the StandardModel and in extended models. In spring 2012 the Tevatron extended the excluded SM Higgs boson mass range to 147 < mH < 179 GeV at 95% CL in the high-mass region beyond the LEP limit. The summer 2012 results for the same dataset pushed the expected limit from 141 GeV down to 139 GeV, while the observed limits remained unchanged. In the low-mass region an excess of data events with respect to the background estimation is observed in the mass range 120 < mH < 135 GeV which causes the limits to be not as stringent as expected. The significance for such an excess anywhere in the full mass range is approximately 2.5s. Focusing on the associated production of a Higgs boson with a W or Z boson and the subsequent decay of the Higgs boson(Asa) to a bottom-antibottom quark pair, evidence for the presence of a new particle, consistent with the SMHiggs boson has been established, with the largest local significance of 3.3σ, corresponding to a global significance of 3.1σ. The Tevatron observation in the given mass range is consistent with the discovery of a new particle of about 125 GeV mass at the LHC. The sensitivity increase in recent years is illustrated owing to the increase in data available and improvements in analysis. The achieved experimental sensitivities are also compared to the previous predictions. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of several conferences related to nuclear physics held in 2011 and 2012. The Fourth International Conference on Proton-Emitting Nuclei held in Bordeaux, France has provided a complete overview of physics with proton-rich nuclei. Morelos, Mexico hosted the XXXV Symposium on Nuclear Physics in January 2012 that addressed topics such as nuclear structure, nuclear reactions and hadron physics.

Soft QCD contributes to all observables at the LHC, due to the presences of underlying event (UE) and pile-up in all events. Both these processes are dominated by multi-parton interactions (MPI), i.e. the result of proton collisions containing more than one partonic interaction due to collective and beam remnant effects. While there is undoubtedly interesting physics involved in MPI, the primary interest of LHC experiments is to characterise and model the behaviour of UE and pile-up sufficiently well that their influence may be cleanly subtracted in the process of searching for new physics signatures at 7 TeV and beyond. I summarise the soft QCD measurements made by ATLAS using the 2010 and early 2011 datasets, and the use of this data to improve Monte Carlo generator models of MPI for use in forthcoming simulation campaigns. [ABSTRACT FROM AUTHOR]

The Compact Muon Solenoid (CMS) detector is a general purpose experiment at the Large Hadron Collider (LHC) accelerator. The CMS trigger performance with proton--proton collisions during the first year of the LHC's operation in 2010 is presented. The CMS trigger system is also described and trigger efficiency results and selected applications for physics analyses are presented. [ABSTRACT FROM AUTHOR]

The Large Hadron Collider accelerates and collides both proton beams and lead beams to the highest energies available in the laboratory. One of the most important global characteristics of such collisions is the multiplicity of produced particles. The ATLAS detector registers passage of charged particles using silicon detectors over a pseudorapidity range of about 5 pseudorapidity units. Several methods of reconstruction of the charged particle multiplicity and angular distribution were developed. These methods range from the full reconstruction of particles and their momenta to an estimate of the number of charged particles based on counting hits registered in a single layer of the Pixel detector. First results obtained from experimental data for p+p interactions and performance studies for heavy ion collisions based on Monte Carlo simulations are discussed. [ABSTRACT FROM AUTHOR]

This paper describes the performance of low energy electron reconstruction and identification at ATLAS with proton-proton collisions at a centre of mass energy of 7 TeV produced by the Large Hadron Collider. This study was performed with a sample collected from April to June 2010, corresponding to an integrated luminosity of 78 nb-1. We present the reconstruction of prompt J/ψ mesons decaying into e+e- pairs. These electrons can be used to study the detector performance at low energy, as a complement of higher energy electrons coming from W and Z decays. A sample of ~ 220 J/ψ events can be selected. Their mass values reconstructed with different inputs agree with the values expected from the initial calibration of the ATLAS detector. The kinematics and shower shape distributions (used for identification purpose) have been extracted from the J/ψ data sample and show a good agreement with the simulation. [ABSTRACT FROM AUTHOR]

This article discusses the recent tests of the Standard Model using pp-collision events at √s = 7 TeV collected with the ATLAS detector at the Large Hadron Collider (LHC) during 2010 data taking period. The paper focuses on measurements of hard and soft sectors of quantum chromodynamics (QCD), a theory describing interactions of quarks and gluons. [ABSTRACT FROM AUTHOR]

The fabrication of 3D detectors which requires bulk micromachining of columnar electrodes has been realized with advancements in MEMS technology. Since the fabrication of the first 3D prototype in Stanford Nanofabrication Facility in 1997, a significant effort has been put forth to transfer the 3D detector technology to large scale manufacturing for future high luminosity collider experiments, in which the radiation hardness will be the primary concern, and other applications such as medical imaging and X-ray imaging for molecular biology. First, alternative 3D structures, single type column (STC) and double-side double type column (DDTC) 3D detectors, were produced at FBK-irst (Trento, Italy) and CNM-Barcelona (Spain), and assessed thoroughly to improve the production technology towards the standard full-3D detectors. The 3D collaboration has been extended to include SINTEF (Norway), which is committed to small to medium scale production of active edge full-3D silicon sensors. This paper focuses on p-type 3D detectors compatible with the CMS pixel front end electronics from the second run of fabrication at SINTEF clean room facilities. The sensors that passed the wafer level electrical characterization have been bump-bonded at IZM (Germany), assembled into modules and wire-bonded for functional characterization at Purdue University. We report the leakage current characteristics, bump-bond quality, threshold, noise, and gain measurement results of these 3D modules as well as the preliminary beam test data taken at Fermi National Accelerator Laboratory. [ABSTRACT FROM AUTHOR]

The latest status of LHC and the performances of ATLAS and CMS detectors are summarized in the first part. Physics potential to solve the origin of the ElectroWeak Symmetry Breaking is summarized in the 2nd part, focusing especially on two major scenarios, (1) the light Higgs boson plus SUSY and (2) the Strong Coupling Gauge Theory. Both ATLAS and CMS detectors have the excellent potential to discover them, and we can perform crucial test on the ElectroWeak Symmetry Breaking. [ABSTRACT FROM AUTHOR]

The project presented in this paper, the CMS muon detector, is fully described in Ref. 1. It was designed from 1991 to 19945 by a community of physicists and engineers from universities and institutes of several countries. The details of the design were fixed in 1997 with the submission of the CMS Muon Technical Design Report.4 This paper reflects the views, the memoirs and the understanding of the author, who is responsible for the choice of the subjects and for any omission or error. [ABSTRACT FROM AUTHOR]

Abstract: LHCb, one of the four LHC experiments, is dedicated to the study of CP violation and rare decays in the B meson sector. It aims at completing the understanding of the quark flavor physics and at revealing signs of new physics beyond the standard model. The goal of the LHCb calorimeter is twofold. On the one hand, the calorimeter system has to provide a fast response for the first level trigger (L0) on the nature of the meson decay. Thus, the scintillator pad detector and the preshower provide a good / charged particle and electron/ separation and the electromagnetic and hadronic calorimeters give a fast transverse energy determination. On the other hand, it provides offline precision measurements and particle identification. The calorimeter system consists of four sub-detectors. They are described in the first section, emphasising the technical choices and the similarities among those components. The second part concerns the monitoring and calibration tools and procedures that will be applied to have a satisfactory running of the detector. [Copyright &y& Elsevier]

Abstract: ALICE is the general purpose experiment at the LHC dedicated to the study of heavy-ion collisions. The electromagnetic calorimeter (EMCal) is a late addition to the ALICE suite of detectors with first modules installed in ALICE this year. The EMCal is designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The EMCal is a Pb/scintillator sampling shish-kebab type calorimeter. The EMCal construction, readout, and performance in beam tests at the CERN SPS and PS are described. [Copyright &y& Elsevier]

Abstract: LHCf is a high-energy physics experiment designed to study the forward production of neutral particles in proton–proton collisions at the LHC. The set-up consists of two small calorimetric systems symmetrically placed 140m away on both the sides of the ATLAS interaction point. Results from the experiment will provide valuable information to the calibration of the nuclear interaction models used in the Monte Carlo codes for air-shower simulations, which are of great importance for present and future ground-based cosmic-ray experiments. In particular, since LHCf will start taking data in the first phase of operation of the LHC (during the beam commissioning phase at energy) and will complete its data taking at the beginning of the runs (laboratory equivalent collision energy ), it will span an energy range up to the region between the “knee” and the GZK cut-off of the cosmic-ray spectrum. [Copyright &y& Elsevier]

Collaboration between France and Japan on studies with fast RI (radioactive isotope) beams and related technical developments started in 1980s, when the GANIL accelerators and RIKEN cyclotron complex started operation and RI beam production technique was developed. Several examples of collaboration on nuclear physics and nuclear astrophysics experiments including related technical development are discussed. [ABSTRACT FROM AUTHOR]

The shell structure of the nucleus implies the existence of magic numbers. Since several years many indications have been accumulated, theoretically as well as through experiments at various laboratories around the world, that if one moves away from stability, the location of the magic numbers shifts as an inescapable consequence of the evolving nature of the nuclear force itself. In this respect, it is the balance between the tensor and spin-orbit components that seems particularly instrumental. Illustrative examples from recent experiments at Ganil, at the neutron-rich and proton-rich side of the nuclear chart for N or Z equal 20 or 28, will be presented here. [ABSTRACT FROM AUTHOR]

Three-dimensional (3-D) silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrate into the bulk material in contrast to standard Si detectors with planar electrodes on the top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as, for example, the radiation environment expected in an upgrade to the Large Hadron Collider at CERN. For the first time, several 3-D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here, we report results on unirradiated devices with three 3-D electrodes per 50 x 400 μm² pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9%±0.1% for tracks incident parallel to the electrodes and of 99.9%±0.1% for tracks incident at 15° are measured. The homogeneity and charge sharing of the efficiency over the pixel area are measured. [ABSTRACT FROM AUTHOR]

Results are presented on the discovery potential for MSSM neutral Higgs bosons in the mh-max scenario. The region of large cosβ, between 15 and 50, and mass between ≈95 and 130 GeV is considered in the framework of the ATLAS experiment at the large hadron collider (LHC), for a centre-of-mass energy $\sqrt{s}$ = 14 TeV. This parameter region is not fully covered by the present data either from LEP or from Tevatron. The h/A bosons, supposed to be very close in mass in that region, are studied in the channel h/A→μ+μ- accompanied by two b-jets. The study includes a method to control the most copious background, Z→μ+μ- accompanied by two b-jets. A possible contribution of the H boson to the signal is also considered. [ABSTRACT FROM AUTHOR]

The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams. The energy stored in each beam is about 350 MJ. If there is a failure in an element of the accelerator, the resulting beam losses could cause damage not only to the accelerator itself, but also to the physics experiments installed. Within the Compact Muon Solenoid experiment (CMS), the use of a Beam Condition Monitor (BCM) is planned to monitor a possible fast increase of the particle flux near the interaction point. The system will flag the onset of adverse beam conditions within the CMS experiment, and, if necessary, input into the beam abort system of the LHC requesting a fast beam dump. Constraints on BCM design from radiation hardness, a minimal material and services budget, and the need for fast signals from sensors with high sensitivity and a large dynamic range, have led to the investigation of synthetic chemical vapor deposited (CVD) diamond for the BCM sensor. In a 5 GeV hadron beam the response of CVD diamonds was tested in fluxes ranging from single minimium ionizing particles (MIPs) to 108 MIPs per cm2, delivered over 40 ns. The signal response, linearity, and stability of both unirradiated and irradiated sensors were tested over this flux range, and will be presented herein. The results confirm the applicability of CVD diamond for this beam monitoring application. [ABSTRACT FROM AUTHOR]

The NEMO-3 detector has been taking data in the Fréjus underground laboratory (LSM, France) since February 2003 and is devoted to the search for neutrinoless double-beta decay (0 νββ). After 389 effective days of data collection from February 2003 until September 2004 (Phase I), no evidence for neutrinoless double-beta decay was found from ∼7 kg of 100Mo and ∼1 kg of 82Se. The corresponding limits for the half-lives are T 1/2(0 νββ) > 4.6 × 1023 yr for 100Mo and T 1/2(0 νββ) > 1.0 × 1023 yr for 82Se (90% C.L.). They lead to the following limits for the effective Majorana neutrino mass: 〈 m ν〉 < 0.7–2.8 eV for 100Mo and 〈 m ν〉 < 1.8–4.9 eV for 82Se. The half-lives of the two-neutrino double-beta decay (2 νββ) have been measured for 100Mo, 82Se, 116Cd, 150Nd, and 96Zr and reported here as well. [ABSTRACT FROM AUTHOR]

The CMS experiment at the LHC, CERN, will operate the largest tracker in the world entirely made of silicon detectors. The collaboration is facing the quality assurance work to prove the reliability and performance of the various parts produced by industry. A status report on the CMS Tracker is given, including the validation of single modules up to larger integrated substructures [ABSTRACT FROM PUBLISHER]