Searcharxiv⌕ Search

SEARCH · Searcharxiv

Results for “physics.ins-det”

Search indexed arXiv papers on artificial intelligence, large language models, computer vision and robotics. Read source abstracts and follow links to arXiv.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
arXiv2011

Simulation of the SONGS Reactor Antineutrino Flux Using DRAGON

For reactor antineutrino experiments, a thorough understanding of the fuel composition and isotopic evolution is of paramount importance for the extraction of $θ_{13}$. To accomplish these goals, we employ the deterministic lattice code DRAGON, and analyze the instantaneous antineutrino rate from the San Onofre Nuclear Generating Station (SONGS) Unit 2 reactor in California. DRAGON's ability to predict the rate for two consecutive fuel cycles is examined.

physics.ins-det↗
arXiv2011

Attenuation study for Tibet Water Cherenkov Muon Detector Array-A

This work aims at online calibrating the signal attenuation of the long cable used in Tibet Water Cherenkov Muon detector array-A (Tibet MD-A) under the 37 000 m2 Tibet air shower array. Based on the waterproof connection of the PMT (R3600_06) with the signal cable, and the characters of the high voltage divider, terminal reflection method is explored and used for measuring the signal attenuation with a practical way to eliminate the contribution of the pulse baseline (pedestal). Comparison measurement between it and QDC (Charge-to-Digital Conversion) data taking method are carried out by using open-ended cables, confirming that terminal reflection method is a fast and convenient method, and suitable to online calibrate the signal attenuation for Tibet MD-A. At 26\degree C, the measured attenuation coefficient with the 250-m cable, permanently connected to the PMT, is ~13.9%. Also, the cable frequency response is measured by using the sinusoidal signals, which could be used to study the time dispersion of the real signal produced with Tibet MD-A detector via Fourier analysis.

physics.ins-det↗
arXiv2011

To Re-Consider the One-Way Speed of Light Using Fizeau-Type-Coupled-Slotted-Disks

The isotropy of the speed of light - the fundamental postulate of Special Relativity (SR) constrains conceptions of time, space and the existence of a preferred cosmological reference frame. Consequently, this phenomenon has been subject to considerable experimental scrutiny. Most isotropy tests are two-way Michelson-Morley type tests which established the isotropy of the two-way speed in 1881. These approaches provide no experimental limit for the one-way (single-trip) isotropy of the speed of light which is still unresolved. Here we consider Fizeau-type experiments to test the isotropy of the one-way speed of light. Our theoretical and experimental design suggests that our approach is 2600 times more sensitive than that of previous Fizeau-type experiments and 2000 times more sensitive than Michelson-Morley type two-way tests. We present our experimental methodology as well as initial calibration results for our experimental apparatus.

physics.ins-det↗
arXiv2011

Gamma Background Measurements at BEO Moussala

Recent measurements of radiation gamma background at high mountain altitude, namely at Basic Environmental Observatory Moussala (42°10' 45" N; 23° 35'07"E, 2925m a.s.l.) are carried out. The measurements are fulfilled with several different devices, namely IGS-421 gamma probe and MDU Liulin spectrometer. The used instrumentation with their characteristics is described. The obtained results are compared with previously obtained measurements carried out with NaI SAPHYMO gamma probe. In addition the measurements are compared with TLD data. The obtained results from measurements are widely discussed. The contribution of galactic cosmic rays to dose rate is estimated on the basis of a numerical model. The model is based on a full Monte Carlo simulation of cosmic ray induced nuclear-electromagnetic-muon cascade in the atmosphere. The simulation is carried out with CORSIKA 6.52 code using FLUKA 2006 and QGSJET II hadron interaction models. The application of the model is briefly discussed.

physics.ao-ph↗
arXiv2011

Preliminary design of a RESPER probe prototype, configured in a multi dipole-dipole array

The RESPER probe has been assembled, except the ferrules that must ensure the contact, by insulating materials and more specifically in Tufnol, as regards the support plates, and Teflon, as regards the standoffs. A series of holes has been drilled on the surface of support plates in order to allow approaching each other of the two central electrodes to external ones, from a minimum of 4.29 cm to a maximum of 10 cm. The dipole-dipole array defined by the integer parameter n = 6 could not be implemented, as the positioning of suitable "spring" shafts requires 6 mm holes and an adequate space could not be available to carry out the drilling. The presence of these "spring" shafts allows reaching a right prominence of the tip from the base and, at the same time, a certain amount of pressure which ensures the proper adherence to the artifact that must be tested. There is a brass screw within each shaft, which edge has been turned to the measurement of 1.4 mm. Four metal spacers are replaced of time in time depending on the configuration that is to be adopted. The achievement of height l(n) from the plates is ensured by the presence of metallic spacers. To complete the description, a copper cable, 1 m long and with a 4.0 mm2 section area, has been welded to the head of each electrode. The two transmitting or reading cables are kept at a fixed distance L(n) between them by means of Teflon rods in which has been applied the same series of holes existing on the Tufnol plates.

physics.geo-ph↗
arXiv2011

Relativity, Doppler shifts, and retarded times in deriving the correction for the finite speed of light: a comment on 'Second-order Doppler-shift corrections in free-fall absolute gravimeters'

In the article (Rothleitner and Francis 2011 Metrologia 48 187-195) the correction due to the finite speed of light in absolute gravimeters is analyzed from the viewpoint of special relativity. The relativistic concepts eventually lead to the two classical approaches to the problem: analysis of the beat frequency, and introduction of the retarded times. In the first approach, an additional time delay has to be assumed, because the frequency of the beam bounced from the accelerated reflector differs at the point of reflection from that at the point of interference. The retarded times formalism is equivalent to a single Doppler shift, but results in the same correction as the beat frequency approach, even though the latter is explicitly combines two Doppler shifts. In our comments we discuss these and other problems we found with the suggested treatment of the correction.

physics.ins-det↗
arXiv2012

Using the cathode surface of straw tube for measuring the track coordinates along the wire

The coordinate detectors based on straw tubes provide a high accuracy of the radial coordinate measurement using the drift time and a small amount of matter in the way of the measured particles. However, the measurement of the coordinate along the wire constitutes a problem. This paper proposes a method for measuring the hit coordinate along the wire with an accuracy better than 1 mm in a straw tube detector using the signals from the cathodes of the detector.

physics.ins-det↗
arXiv2011

Micromagnetic study of flux-closure states in Fe dots using quantitative Lorentz Microscopy

A micromagnetic study of epitaxial micron-sized iron dots is reported through the analysis of Fresnel contrast in Lorentz Microscopy. Their use is reviewed and developed through analysis of various magnetic structures in such dots. Simple Landau configuration is used to investigate various aspects of asymmetric Bloch domain walls. The experimental width of such a complex wall is first derived and its value is discussed with the help of micromagnetic simulations. Combination of these two approaches enables us to define what is really extracted when estimating asymmetric wall width in Lorentz Microscopy. Moreover, quantitative data on the magnetization inside the dot is retrieved using phase retrieval as well as new informations on the degrees of freedom of such walls. Finally, it is shown how the existence and the propagation of a surface vortex can be characterized and monitored. This demonstrates the ability to reach a magnetic sensitivity a priori hidden in Fresnel contrast, based on an original image treatment and backed-up by the evaluation of contrasts obtained from micromagnetic simulations.

cond-mat.mtrl-sci↗
arXiv2011

Recent results in the search for dark matter with noble liquid detectors

The field of dark matter direct detection has seen important contributions in recent years from experiments involving liquid noble gases, specifically liquid argon and liquid xenon. These detection media offer many properties deemed useful in this search, including fast scintillation response, charge readout, 3-D position reconstruction, and nuclear recoil discrimination. Part of the very rapid emergence and dominance of noble liquids is due to the fact that these technologies are easily scalable to nearly arbitrary size and mass. However, the physics impact of recent results has called into question our understanding of the low-energy response of these detection media, in light of apparent contradictions with a possible low-mass WIMP signal observed in the DAMA/LIBRA and CoGeNT experiments. I discuss recent results and examine the details of this inconsistency.

hep-ex↗
arXiv2011

Testing Machine for Expansive Mortar

The correct evaluation of a material property is fundamental to, on their application; they met all expectations that were designed for. In development of an expansive cement for ornamental rocks purpose, was denoted the absence of methodologies and equipments to evaluate the expansive pressure and temperature of expansive cement during their expansive process, having that data collected in a static state of the specimen. In that paper, is described equipment designed for evaluation of pressure and temperature of expansive cements applied to ornamental rocks.

physics.ins-det↗
arXiv2011

Electrostatic accelerometer with bias rejection for deep space gravitation tests

The trajectory of an interplanetary spacecraft can be used to test gravitation in the Solar System. Its determination relies on radio tracking and is limited by the uncertainty on the spacecraft non-gravitational acceleration. The addition of an accelerometer on board provides another observable which measures the departure of the probe from geodesic motion. Such a concept has been proposed for the OSS mission which embarks the Gravity Advanced Package. This instrument, which is the focus of this article, is designed to make unbiased acceleration measurements.

physics.ins-det↗
arXiv2011

Instrumentation2: Other instruments, ghost/satellite bunch monitoring, halo, emittance, new developments

In order to estimate in absolute terms the luminosity of LHC certain beam parameters have to be measured very accurately. In particular the total beam current and the relative distribution of the charges around the ring, the transverse size of the beams at the interaction points and the relative position of the beams at the interaction point. The experiments can themselves measure several of these parameters very accurately thanks to the versatility of their detectors, other parameters need however to be measured using the monitors installed on the machine. The beam instrumentation is usually built for the purpose of aiding the operation team in setting up and optimizing the beams, often this only requires precise relative measurements and therefore the absolute scale is usually not very precisely calibrated. The luminosity calibration requires several machine-side instruments to be pushed beyond their initial scope.

physics.ins-det↗
arXiv2011

Odyssey 2 : A mission toward Neptune and Triton to test General Relativity

Odyssey 2 will be proposed in December 2010 for the next call of M3 missions for Cosmic Vision 2015-2025. This mission, under a Phase 0 study performed by CNES, will aim at Neptune and Triton. Two sets of objectives will be pursued. The first one is to perform a set of gravitation experiments at the Solar System scale. Experimental tests of gravitation have always shown good agreement with General Relativity. There are however drivers to continue testing General Relativity, and to do so at the largest possible scales. From a theoretical point of view, Einstein's theory of gravitation shows inconsistencies with a quantum description of Nature and unified theories predict deviations from General Relativity. From an observational point of view, as long as dark matter and dark energy are not observed through other means than their gravitational effects, they can be considered as a manifestation of a modification of General Relativity at cosmic scales. The scientific objectives are to: (i) test the gravitation law at the Solar System scale; (ii) measure the Eddington parameter; and (iii) investigate the navigation anomalies during fly-bys. To fulfil these objectives, the following components are to be on board the spacecraft: (i) the Gravity Advanced Package (GAP), which is an electrostatic accelerometer to which a rotating stage is added; (ii) radio-science; (iii) laser ranging, to improve significantly the measure of the Eddington parameter. The second set of objectives is to enhance our knowledge of Neptune and Triton. Several instruments dedicated to planetology are foreseen: camera, spectrometer, dust and particle detectors, and magnetometer. Depending on the ones kept, the mission could provide information on the gravity field, the atmosphere and the magnetosphere of the two bodies as well as on the surface geology of Triton and on the nature of the planetary rings around Neptune.

gr-qc↗
arXiv2011

Phonon Quasidiffusion in Cryogenic Dark Matter Search Large Germanium Detectors

We present results on quasidiffusion studies in large, 3 inch diameter, 1 inch thick [100] high purity germanium crystals, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare data obtained in two different detector types, with different phonon sensor area coverage, with results from a Monte Carlo. The Monte Carlo includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels.

physics.ins-det↗
arXiv2012

Study of radiation damage induced by 12 keV X-rays in MOS structures built on high resistivity n-type silicon

Imaging experiments at the European X-ray Free Electron Laser (XFEL) require silicon pixel sensors with extraordinary performance specifications: Doses of up to 1 GGy of 12 keV photons, up to 10^5 12 keV photons per pixel of 200 \mum \times 200 \mum arriving within less than 100 fs, and a time interval between XFEL pulses of 220 ns. To address these challenges, in particular the question of radiation damage, the properties of the SiO_2 layer and of the Si-SiO_2 interface using MOS capacitors manufactured on high resistivity n-type silicon irradiated to X-ray doses between 10 kGy and 1 GGy, have been studied. Measurements of Capacitance/Conductance-Voltage (C/G-V) at different frequencies, as well as Thermal Dielectric Relaxation Current (TDRC) have been performed. The data can be described by a radiation dependent oxide charge density and three dominant radiation-induced interface states with Gaussian-like energy distributions in the silicon band gap. It is found that the densities of the fixed oxide charges and of the three interface states increase up to dose values of approximately 10 MGy and then saturate or even decrease. The shapes and the frequency dependences of the C/G-V measurements can be quantitatively described by a simple model using the parameters extracted from the TDRC measurements.

physics.ins-det↗
arXiv2011

United Nations Basic Space Science Initiative: 2011 Status Report on the International Space Weather Initiative

The UNBSSI is a long-term effort for the development of astronomy and space science through regional and international cooperation in this field on a worldwide basis. A series of workshops on BSS was held from 1991 to 2004 (India 1991, Costa Rica and Colombia 1992, Nigeria 1993, Egypt 1994, Sri Lanka 1995, Germany 1996, Honduras 1997, Jordan 1999, France 2000, Mauritius 2001, Argentina 2002, and China 2004; http://www.seas.columbia.edu/~ah297/un-esa/) and addressed the status of astronomy in Asia and the Pacific, Latin America and the Caribbean, Africa, and Western Asia. One major recommendation that emanated from these workshops was the establishment of astronomical facilities in developing nations for research and education programmes at the university level. Such workshops on BSS emphasized the particular importance of astrophysical data systems and the virtual observatory concept for the development of astronomy on a worldwide basis. Pursuant to resolutions of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) and its Scientific and Technical Subcommittee, since 2005, these workshops focused on the International Heliophysical Year 2007 (UAE 2005, India 2006, Japan 2007, Bulgaria 2008, Ro Korea 2009; http://www.unoosa.org/oosa/SAP/bss/ihy2007/index.html). Starting in 2010, the workshops focus on the International Space Weather Initiative (ISWI) as recommended in a three-year-work plan as part of the deliberations of UNCOPUOS (http://www.stil.bas.bg/ISWI/). Workshops on the ISWI have been scheduled to be hosted by Egypt in 2010 for Western Asia, Nigeria in 2011 for Africa, and Ecuador in 2012 for Latin America and the Caribbean. Currently, 14 IHY/ISWI instrument arrays with > 600 instruments are operational in 95 countries.

physics.space-ph↗