Physics - Instrumentation and Detectors Publications (50)

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Physics - Instrumentation and Detectors Publications

Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEGII experiment, at PSI, Switzerland, investigates the forbidden decay $\mu^+ \to \mathrm{e}^+ \gamma$. Exploiting the most intense muon beam of the world. Read More


In this document, the technical details of the JSNS$^2$ (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment are described. The search for sterile neutrinos is currently one of the hottest topics in neutrino physics. The JSNS$^2$ experiment aims to search for the existence of neutrino oscillations with $\Delta m^2$ near 1 eV$^2$ at the J-PARC Materials and Life Science Experimental Facility (MLF). Read More


The use of Standard Reference Materials (SRM) from the National Institute of Standards and Technology (NIST) for quantitative analysis of chemical composition using Synchrotron based X-Ray Florescence (SR-XRF) and Scanning Transmission X-Ray Microscopy (STXM) is common. These standards however can suffer from inhomogeneity in chemical composition and thickness and often require further calculations, based on sample mounting and detector geometry, to obtain quantitative results. These inhomogeneities negatively impact the reproducibility of the measurements and the quantitative measure itself. Read More


In this article we present an automatic method for charge and mass identification of charged nuclear fragments produced in heavy ion collisions at intermediate energies. The algorithm combines a generative model of DeltaE - E relation and a Covariance Matrix Adaptation Evolutionary Strategy (CMA-ES). The CMA-ES is a stochastic and derivative-free method employed to search parameter space of the model by means of a fitness function. Read More


MicroBooNE (the Micro Booster Neutrino Experiment) is a short-baseline neutrino experiment based on the technology of a liquid-argon time-projection chamber (LArTPC), and has recently completed its first year of data-taking in the Fermilab Booster Neutrino Beam. It aims to address the anomalous excess of events with an electromagnetic final state in MiniBooNE, to measure neutrino-argon interaction cross sections, and to provide relevant R\&D for the future LArTPC experiments, such as DUNE. In these proceedings, we present the first reconstructed energy spectrum of Michel electrons from cosmic muon decays, the first kinematic distributions of the candidate muon tracks from $\nu_{\mu}$-argon charged-current interactions, and a demonstration of an electromagnetic shower reconstruction from $\pi^0$s produced by $\nu_{\mu}$-argon charged-current interactions. Read More


A system for online measurement of the transverse beam emittance was developed. It is named $^{4}$PrOB$\varepsilon$aM (4-Profiler Online Beam Emittance Measurement) and was conceived to measure the emittance in a fast and efficient way using the multiple beam profiler method. The core of the system is constituted by four consecutive UniBEaM profilers, which are based on silica fibers passing across the beam. Read More


2017May
Affiliations: 1Korea Advanced Institute of Science and Technology, 2Osaka University, 3Institute for Basic Science, 4Technische Universität Dresden

This paper discusses how to improve the experimental sensitivity of the $\mu^- + N(A,Z) \rightarrow e^+ + N(A,Z-2)$ conversion in a muonic atom, which is a charged lepton number and lepton flavor violating (CLNFV) process. Currently, the measurement of this process is planned with future experiments to search for the $\mu^- -e^-$ conversion with an aluminum target. We demonstrate that a search for $\mu^--e^+$ would be limited to a sensitivity improvement less than a factor of ten due to backgrounds from radiative muon capture, whereas the $\mu^--e^-$ conversion is anticipated to have four orders of magnitude of improvement in its experimental sensitivity. Read More


2017May
Authors: MicroBooNE collaboration, R. Acciarri, C. Adams, R. An, J. Anthony, J. Asaadi, M. Auger, L. Bagby, S. Balasubramanian, B. Baller, C. Barnes, G. Barr, M. Bass, F. Bay, M. Bishai, A. Blake, T. Bolton, B. Bullard, L. Camilleri, D. Caratelli, B. Carls, R. Castillo Fernandez, F. Cavanna, H. Chen, E. Church, D. Cianci, E. Cohen, G. H. Collin, J. M. Conrad, M. Convery, J. I. Crespo-Anadon, G. De Geronimo, M. Del Tutto, D. Devitt, S. Dytman, B. Eberly, A. Ereditato, L. Escudero Sanchez, J. Esquivel, A. A. Fadeeva, B. T. Fleming, W. Foreman, A. P. Furmanski, D. Garcia-Gamez, G. T. Garvey, V. Genty, D. Goeldi, S. Gollapinni, N. Graf, E. Gramellini, H. Greenlee, R. Grosso, R. Guenette, A. Hackenburg, P. Hamilton, O. Hen, J. Hewes, C. Hill, J. Ho, G. Horton-Smith, A. Hourlier, E. -C. Huang, C. James, J. Jan de Vries, C. -M. Jen, L. Jiang, R. A. Johnson, J. Joshi, H. Jostlein, D. Kaleko, G. Karagiorgi, W. Ketchum, B. Kirby, M. Kirby, T. Kobilarcik, I. Kreslo, A. Laube, S. Li, Y. Li, A. Lister, B. R. Littlejohn, S. Lockwitz, D. Lorca, W. C. Louis, M. Luethi, B. Lundberg, X. Luo, A. Marchionni, C. Mariani, J. Marshall, D. A. Martinez Caicedo, V. Meddage, T. Miceli, G. B. Mills, J. Moon, M. Mooney, C. D. Moore, J. Mousseau, R. Murrells, D. Naples, P. Nienaber, J. Nowak, O. Palamara, V. Paolone, V. Papavassiliou, S. F. Pate, Z. Pavlovic, E. Piasetzky, D. Porzio, G. Pulliam, X. Qian, J. L. Raaf, V. Radeka, A. Rafique, S. Rescia, L. Rochester, C. Rudolf von Rohr, B. Russell, D. W. Schmitz, A. Schukraft, W. Seligman, M. H. Shaevitz, J. Sinclair, A. Smith, E. L. Snider, M. Soderberg, S. Soldner-Rembold, S. R. Soleti, P. Spentzouris, J. Spitz, J. St. John, T. Strauss, A. M. Szelc, N. Tagg, K. Terao, M. Thomson, C. Thorn, M. Toups, Y. -T. Tsai, S. Tufanli, T. Usher, W. Van De Pontseele, R. G. Van de Water, B. Viren, M. Weber, D. A. Wickremasinghe, S. Wolbers, T. Wongjirad, K. Woodruff, T. Yang, L. Yates, B. Yu, G. P. Zeller, J. Zennamo, C. Zhang

The low-noise operation of readout electronics in a liquid argon time projection chamber (LArTPC) is critical to properly extract the distribution of ionization charge deposited on the wire planes of the TPC, especially for the induction planes. This paper describes the characteristics and mitigation of the observed noise in the MicroBooNE detector. The MicroBooNE's single-phase LArTPC comprises two induction planes and one collection sense wire plane with a total of 8256 wires. Read More


We present a method to carry out electrical and opto-electronic measurements on 2D materials using carbon fiber microprobes to directly make electrical contacts to the 2D materials without damaging them. The working principle of this microprobing method is illustrated by measuring transport in MoS2 flakes in vertical (transport in the out-of-plane direction) and lateral (transport within the crystal plane) configurations, finding performances comparable to those reported for MoS2 devices fabricated by conventional lithographic process. We also show that this method can be used with other 2D materials. Read More


This paper presents LongHCPulse: software which enables heat capacity to be collected on a Quantum Design PPMS using a long-pulse method. This method, wherein heat capacity is computed directly from the time derivative of sample temperature, is necessary for probing first order transitions and shortens the measurement time by a factor of five. LongHCPulse also includes plotting utilities based on the Matplotlib library. Read More


2017May
Authors: C. E. Aalseth, F. Acerbi, P. Agnes, I. F. M. Albuquerque, T. Alexander, A. Alici, A. K. Alton, P. Ampudia, P. Antonioli, S. Arcelli, R. Ardito, I. J. Arnquist, D. M. Asner, H. O. Back, G. Batignani, E. Bertoldo, S. Bettarini, M. G. Bisogni, V. Bocci, A. Bondar, G. Bonfini, W. Bonivento, M. Bossa, B. Bottino, R. Bunker, S. Bussino, A. Buzulutskov, M. Cadeddu, M. Cadoni, A. Caminata, N. Canci, A. Candela, C. Cantini, M. Caravati, M. Cariello, M. Carlini, M. Carpinelli, A. Castellani, S. Catalanotti, V. Cataudella, P. Cavalcante, R. Cereseto, Y. Chen, A. Chepurnov, A. Chiavassa, C. Cicalò, L. Cifarelli, M. Citterio, A. G. Cocco, M. Colocci, S. Corgiolu, G. Covone, P. Crivelli, I. D'Antone, M. D'Incecco, M. D. Da Rocha Rolo, M. Daniel, S. Davini, A. De Candia, S. De Cecco, M. De Deo, G. De Filippis, G. De Guido, G. De Rosa, G. Dellacasa, P. Demontis, A. V. Derbin, A. Devoto, F. Di Eusanio, G. Di Pietro, C. Dionisi, A. Dolgov, I. Dormia, S. Dussoni, A. Empl, A. Ferri, C. Filip, G. Fiorillo, K. Fomenko, D. Franco, G. E. Froudakis, F. Gabriele, A. Gabrieli, C. Galbiati, P. Garcia Abia, A. Gendotti, A. Ghisi, S. Giagu, G. Gibertoni, C. Giganti, M. Giorgi, G. K. Giovanetti, M. L. Gligan, A. Gola, O. Gorchakov, A. M. Goretti, F. Granato, M. Grassi, J. W. Grate, G. Y. Grigoriev, M. Gromov, M. Guan, M. B. B. Guerra, M. Guerzoni, M. Gulino, R. K. Haaland, B. Harrop, E. W. Hoppe, S. Horikawa, B. Hosseini, D. Hughes, P. Humble, E. V. Hungerford, An. Ianni, S. Jimenez Cabre, T. N. Johnson, K. Keeter, C. L. Kendziora, S. Kim, G. Koh, D. Korablev, G. Korga, A. Kubankin, R. Kugathasan, M. Kuss, X. Li, M. Lissia, G. U. Lodi, B. Loer, G. Longo, R. Lussana, L. Luzzi, Y. Ma, A. A. Machado, I. N. Machulin, L. Mais, A. Mandarano, L. Mapelli, M. Marcante, A. Margotti, S. M. Mari, M. Mariani, J. Maricic, M. Marinelli, D. Marras, C. J. Martoff, M. Mascia, A. Messina, P. D. Meyers, R. Milincic, A. Moggi, S. Moioli, S. Monasterio, J. Monroe, A. Monte, M. Morrocchi, W. Mu, V. N. Muratova, S. Murphy, P. Musico, R. Nania, J. Napolitano, A. Navrer Agasson, I. Nikulin, V. Nosov, A. O. Nozdrina, N. N. Nurakhov, A. Oleinik, V. Oleynikov, M. Orsini, F. Ortica, L. Pagani, M. Pallavicini, S. Palmas, L. Pandola, E. Pantic, E. Paoloni, G. Paternoster, V. Pavletcov, F. Pazzona, K. Pelczar, L. A. Pellegrini, N. Pelliccia, F. Perotti, R. Perruzza, C. Piemonte, F. Pilo, A. Pocar, D. Portaluppi, S. S. Poudel, D. A. Pugachev, H. Qian, B. Radics, F. Raffaelli, F. Ragusa, K. Randle, M. Razeti, A. Razeto, V. Regazzoni, C. Regenfus, B. Reinhold, A. L. Renshaw, M. Rescigno, Q. Riffard, A. Rivetti, A. Romani, L. Romero, B. Rossi, N. Rossi, A. Rubbia, D. Sablone, P. Salatino, O. Samoylov, W. Sands, M. Sant, R. Santorelli, C. Savarese, E. Scapparone, B. Schlitzer, G. Scioli, E. Sechi, E. Segreto, A. Seifert, D. A. Semenov, S. Serci, A. Shchagin, L. Shekhtman, E. Shemyakina, A. Sheshukov, M. Simeone, P. N. Singh, M. D. Skorokhvatov, O. Smirnov, G. Sobrero, A. Sokolov, A. Sotnikov, C. Stanford, G. B. Suffritti, Y. Suvorov, R. Tartaglia, G. Testera, A. Tonazzo, A. Tosi, P. Trinchese, E. V. Unzhakov, A. Vacca, M. Verducci, T. Viant, F. Villa, A. Vishneva, B. Vogelaar, M. Wada, J. Wahl, S. Walker, H. Wang, Y. Wang, A. W. Watson, S. Westerdale, J. Wilhelmi, R. Williams, M. M. Wojcik, S. Wu, X. Xiang, X. Xiao, C. Yang, Z. Ye, F. Zappa, G. Zappalà, C. Zhu, A. Zichichi, G. Zuzel

We report on the cryogenic characterization of Red Green Blue - High Density (RGB-HD) SiPMs developed at Fondazione Bruno Kessler (FBK) as part of the DarkSide program of dark matter searches with liquid argon time projection chambers. A dedicated setup was used to measure the primary dark noise, the correlated noise, and the gain of the SiPMs at varying temperatures. A custom-made data acquisition system and analysis software were used to precisely characterize these parameters. Read More


In order to extend the direct observation of high-energy cosmic rays up to the PeV region, highly performing calorimeters with large geometrical acceptance and high energy resolution are required. Within the constraint of the total mass of the apparatus, crucial for a space mission, the calorimeters must be optimized with respect to their geometrical acceptance, granularity and absorption depth. CaloCube is a homogeneous calorimeter with cubic geometry, to maximise the acceptance being sensitive to particles from every direction in space; granularity is obtained by relying on small cubic scintillating crystals as active elements. Read More


SHiP (Search for Hidden Particles) is a beam dump experiment proposed at the CERN SPS aiming at the observation of long lived particles very weakly coupled with ordinary matter mostly produced in the decay of charmed hadrons. The beam dump facility of SHiP is also a copious factory of neutrinos of all three kinds and therefore a dedicated neutrino detector is foreseen in the SHiP apparatus. The neutrino detector exploits the Emulsion Cloud Chamber technique with a modular structure, alternating walls of target units and planes of electronic detectors providing the time stamp to the event. Read More


A method for circular e$^-$/e$^+$ accelerator beam energy measurement is proposed. Coordinate of an electron (or a positron) in a focusing magnetic spectrometer built in a circular accelerator depends on its energy, two spectrometer parameters, and the circulating beam energy. The spectrometer parameters can be defined using minimum electron energies from Compton backscattering with two laser wavelengths, and an additional photon coordinate detector. Read More


The Mu2e experiment at Fermilab will search for the charged lepton flavor violating process of neutrino-less $\mu \to e$ coherent conversion in the field of an aluminum nucleus. About $7 \cdot 10^{17}$ muons, provided by a dedicated muon beam line in construction at Fermilab, will be stopped in 3 years in the aluminum target. The corresponding single event sensitivity will be $2. Read More


We test common fluence diagnostics in the regime of very low burnup natural uranium reactor samples. The fluence diagnostics considered are the uranium isotopics ratios $^{235}$U/$^{238}$U and $^{236}$U/$^{235}$U, for which we find simple analytic formulas agree well with full reactor simulation predictions. Both ratios agree reasonably well with one another for fluences in the mid $10^{19}\,\mathrm{n/cm^2}$ range. Read More


As a future charge management light source, UV light-emitting diodes (UV LEDs) offer far superior performance in a range of metrics compared to the mercury lamps used in the past. As part of a qualification program a number of short wavelength UV LEDs have been subjected to a series of lifetime tests for potential use on the Laser Interferometer Space Antenna (LISA) mission. These tests were performed at realistic output levels for both fast and continuous discharging in either a DC or pulsed mode of operation and included a DC fast discharge test spanning 50 days, a temperature dependent pulsed fast discharge test spanning 21 days and a pulsed continuous discharge test spanning 507 days. Read More


The Auger Engineering Radio Array (AERA) aims to detect extensive air showers caused by the interactions of ultra-high energy cosmic rays with the Earth's atmosphere, providing complementary information to the Auger surface, fluorescence and muon detectors. AERA, currently consisting of 124 radio stations, comprises an area of about 6 km$^{2}$. The main objective for exploiting a radio detector is to measure the fundamental air-shower parameters, such as the direction, energy and composition. Read More


We report on the development of an ultralow noise thin-film based SQUID magnetometer. A niobium thin-film pickup coil is connected to the input coil of a SQUID current sensor. The low capacitance of the used sub-micrometer cross-type Josephson junctions enable superior noise performance of the device. Read More


A brief overview of the development of neutrino detectors for long-baseline oscillation experiments at accelerators and reactors is presented. Basic principles and main features of detectors of running accelerator experiments T2K and NOvA sensitive to a first level of CP violation and neutrino mass hierarchy, and reactor experiments Daya Bay, RENO and Double Chooz which measured the mixing angle \theta_13 are discussed. A variety of different experimental techniques is proposed and developed for the next generation oscillation experiments: a 20 kt scintillator detector for the reactor experiment JUNO, a 0. Read More


We present frequency tuning mechanisms for dielectric resonators, which undergo "super-mode" interactions as they tune. The tunable schemes are based on dielectric materials strategically placed inside traditional cylindrical resonant cavities, necessarily operating in Transverse Magnetic modes for use as an axion haloscope. The first technique is based on multiple dielectric disks with radii smaller than that of the cavity. Read More


An array of eight CsI(Tl) detectors has been set up to measure the light charged particles in nuclear reactions using heavy ions from the Pelletron Linac Facility, Mumbai. The energy response of CsI(Tl) detector to $\alpha$-particles from 5 to 40 MeV is measured using radioactive sources and the $^{12}$C($^{12}$C, $\alpha$) reaction populating discrete states in $^{20}$Ne. The energy non-linearity and the count rate effect on the pulse shape discrimination property have also been measured and observed the deterioration of pulse shape discrimination with higher count rate. Read More


The Dark Matter Time Projection Chamber (DMTPC) is a direction-sensitive detector designed to measure the direction of recoiling $^{19}$F and $^{12}$C nuclei in low-pressure CF$_4$ gas using optical and charge readout systems. In this paper, we employ measurements from two DMTPC detectors, with operating pressures of 30-60 torr, to develop and validate a model of the directional response and performance of such detectors as a function of recoil energy. Using our model as a benchmark, we formulate the necessary specifications for a scalable directional detector with sensitivity comparable to that of current-generation counting (non-directional) experiments, which measure only recoil energy. Read More


These proceedings review the two DUNE prototype detectors, namely Single- and Dual-Phase ProtoDUNEs. The detectors, both employing liquid argon Time Projection Chambers (LAr TPCs), are currently being built at CERN as part of the ProtoDUNE experimental programme. Such R&D programme aims at validating the prototypes design and technology, which will eventually be applied to the DUNE Far Detector at the Sanford Underground Research Facility (SURF). Read More


Small-diameter muon drift tube (sMDT) detectors have been developed for upgrades of the ATLAS muon spectrometer. With a tube diameter of 15 mm, they provide an about an order of magnitude higher rate capability than the present ATLAS muon tracking detectors, the MDT chambers with 30 mm tube diameter. The drift-tube design and the construction methods have been optimised for mass production and allow for complex shapes required for maximising the acceptance. Read More


Quantitative thermal imaging has the potential of reliable temperature measurement across an entire field-of-view. This non-invasive technique has applications in aerospace, manufacturing and process control. However, robust temperature measurement on the sub-millimetre (30 {\mu}m) length scale has yet to be demonstrated. Read More


The response of the liquid scintillator (EJ-301 equivalent to NE-213) to the monoenergetic electrons produced in Compton scattered $\gamma$-ray tagging has been carried out for various radioactive $\gamma$-ray sources. The measured electron response is found to be linear up to $\sim$4~MeVee and the resolution of the liquid scintillator at 1~MeVee is observed to be $\sim$~11\%. The pulse shape discrimination and pulse height response of the liquid scintillator for neutrons has been measured using $^7$Li(p,n$_1$)$^7$Be*(0. Read More


An ultra-high magnetic field was generated by the electro-magnetic flux compression technique under a reduced seed magnetic field condition and achieved maximum magnetic field intensity was investigated. An ordinal pickup coil measurement fails due to the dielectric breakdown at around 500 T. On the other hand, by utilizing the magneto-optical Faraday rotation method with a small probe, the measureable maximum magnetic field increased significantly. Read More


One of the major challenges of employing a dual-frequency phase-shifting algorithm for phase retrieval is its sensitivity to noise. Yun et. al [H Yun, B Li, S Zhang. Read More


While it is well known that X-ray tomography using a polychromatic source is non-linear, as the linear attenuation coefficient depends on the wavelength of the X-rays, tomography using near monochromatic sources are usually assumed to be a linear inverse problem. When sources and detectors are not treated as points the measurements are the integrals of the exponentials of line integrals and hence non-linear. In this paper we show that this non-linearity can be observed in realistic situations using both experimental measurements in a gamma-ray tomography system and simulations. Read More


2017May
Affiliations: 1Institut de Física d'Altes Energies, Barcelona, Spain, 2Institut de Física d'Altes Energies, Barcelona, Spain, 3Institut de Física d'Altes Energies, Barcelona, Spain, 4Département de Physique Nucléaire et Corpusculaire, University of Geneva, Geneva, Switzerland, 5Institut de Física d'Altes Energies, Barcelona, Spain, 6Institut de Física d'Altes Energies, Barcelona, Spain, 7Karlsruher Institut für Technologie, Karlsruhe, Germany, 8Institut de Física d'Altes Energies, Barcelona, Spain, 9Département de Physique Nucléaire et Corpusculaire, University of Geneva, Geneva, Switzerland, 10Département de Physique Nucléaire et Corpusculaire, University of Geneva, Geneva, Switzerland, 11University of Liverpool, Liverpool, United Kingdom

An upgrade of the ATLAS experiment for the High Luminosity phase of LHC is planned for 2024 and foresees the replacement of the present Inner Detector (ID) with a new Inner Tracker (ITk) completely made of silicon devices. Depleted active pixel sensors built with the High Voltage CMOS (HV-CMOS) technology are investigated as an option to cover large areas in the outermost layers of the pixel detector and are especially interesting for the development of monolithic devices which will reduce the production costs and the material budget with respect to the present hybrid assemblies. For this purpose the H35DEMO, a large area HV-CMOS demonstrator chip, was designed by KIT, IFAE and University of Liverpool, and produced in AMS 350 nm CMOS technology. Read More


A measurement of ionization yields in noble-gas liquids is relevant to the energy calibration of nuclear recoil detectors for dark matter search and coherent neutrino-nucleus scattering experiments. In this work we further study the ionization yield of nuclear recoils in liquid Ar, using a two-phase detector with an electroluminescence gap and DD neutron generator. The ionization yields of nuclear recoils in liquid Ar were measured at 233 keV and electric fields of 0. Read More


The study of proportional electroluminescence in two-phase argon is relevant in the field of noble-gas liquid detectors for dark matter search and low-energy neutrino experiments. In this work, we continued to study proportional electroluminescence (EL) in two-phase argon doped with a minor (9 ppm) admixture of nitrogen, in the VUV, UV and visible spectral ranges. We confirmed the effect of enhancement of the EL yield, as well as the presence of non-VUV component in addition to that of VUV, in proportional electroluminescence in two-phase Ar. Read More


The NA62 experiment at CERN SPS is aimed to measure the branching ratio of the ultra-rare decay $K^+\rightarrow\pi^+ \nu \bar{\nu}$ with 10\% accuracy. The experiment operates with a 75 GeV/c high intensity (750 MHz) secondary beam. A new detector, named Charged Particle Hodoscope (CHOD), designed to produce an input signal to the L0 trigger processor for events with charged particles produced in kaon decays, has been assembled, installed, integrated in NA62 Data Acquisition System (DAQ) and commissioned in 2016. Read More


The correlation of co-located atomic clocks is difficult to measure because their common-mode noise induced by environment would be canceled out during the comparison measurement. It is like two people sitting on a bus will have no idea that they are moving by simply comparing between themselves until they look outside the window. With the development of fiber-based high-precision frequency transfer technique, we can directly measure the correlation of co-located atomic clocks with the help of remote ones. Read More


A nuclear emulsion with micronized crystals is required for the tracking detection of submicron ionizing particles, which are a target of dark matter detection and other methods. We found that a new production method, named as the PVA-Gelatin Mixing Method (PGMM), could effectively control crystal size from 20 nm to 50 nm. We named two types of an emulsion produced with the new method NIT and UNIT. Read More


2017May

The 20kt Liquid Scintillator (LS) JUNO detector is being constructed by the International Collaboration in China, with the primary goal of addressing the question of neutrino mass ordering (hierarchy). The main challenge for JUNO is to achieve a record energy resolution, ~3% at 1MeV of energy released in the LS, which is required to perform the neutrino mass hierarchy determination. About 20 000 large 20-inch PMTs with high Photon Detection Efficiency (PDE) and good photocathode uniformity will ensure an approximately 80% surface coverage of the JUNO detector. Read More


Recent progress in phase modulation using nanofabricated electron holograms has demonstrated how the phase of an electron beam can be controlled. In this paper, we apply this concept to the correction of spherical aberration in a scanning transmission electron microscope and demonstrate an improvement in spatial resolution. Such a holographic approach to spherical aberration correction is advantageous for its simplicity and cost-effectiveness. Read More


MicroBooNE is a liquid-argon-based neutrino experiment, which began collecting data in Fermilab's Booster neutrino beam in October 2015. Physics goals of the experiment include probing the source of the anomalous excess of electron-like events in MiniBooNE. In addition to this, MicroBooNE is carrying out an extensive cross section physics program that will help to probe current theories on neutrino-nucleon interactions and nuclear effects. Read More


We performed simulations of the resolution function of the 4SEASONS spectrometer at J-PARC by using the Monte Carlo simulation package McStas. The simulations showed reasonably good agreement with analytical calculations of energy and momentum resolutions by using a simplified description. We implemented new functionalities in Utsusemi, the standard data analysis tool used in 4SEASONS, to enable visualization of the simulated resolution function and predict its shape for specific experimental configurations. Read More


2017May
Affiliations: 1Department of Materials, University of Oxford, Oxford, UK, 2Department of Materials, University of Oxford, Oxford, UK, 3Department of Materials, University of Oxford, Oxford, UK, 4Center for Metrology MIKES, Espoo, Finland, 5Inorganic Chemistry Laboratory, University of Oxford, Oxford, UK, 6Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK, 7Department of Materials, University of Oxford, Oxford, UK, 8Department of Materials, University of Oxford, Oxford, UK, 9Department of Materials, University of Oxford, Oxford, UK

The endohedral fullerene $^{15}\mathrm{N@C}_{60}$ has narrow electron paramagnetic resonance lines which have been proposed as the basis for a condensed-matter portable atomic clock. We measure the low-frequency spectrum of this molecule, identifying and characterizing a clock transition at which the frequency becomes insensitive to magnetic field. We infer a linewidth at the clock field of 100 kHz. Read More


In halo dark matter axion search experiments, cylindrical microwave cavities are typically employed to detect signals from the axion-photon conversion. To enhance the conversion power and reduce the noise level, cavities are placed in strong solenoid magnetic fields at sufficiently low temperatures. Exploring high mass regions in cavity-based axion search experiments requires high frequency microwave cavities and thus understanding cavity properties at high frequencies in extreme conditions is deemed necessary. Read More


The design and development of a dual high voltage and high frequency charging system for pulsed power applications is presented. Charging systems for pulsed power generators need to be reliable, rugged and cost efficient. The charging system has been designed to operate at a frequency of 10 kHz, and provide +-100 kV to each of the 47 nF load capacitors within a charging time of 10 seconds. Read More


We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2. Read More


Measurements of the ratio of the proton elastic form factors ($\mu_pG_E/G_M$) using Rosenbluth separation and those using polarization-based techniques show a strong discrepancy, which has persisted both in modern experimental results and in re-analyses of previous data. The most widely accepted hypothesis to explain this discrepancy is the treatment of the contributions from hard two-photon exchange (TPE) to elastic electron-proton scattering in the radiative corrections applied to the Rosenbluth separation measurements. Calculations of the hard TPE contribution are highly model dependent, but the effect may be measured experimentally with a precise determination of the ratio of the positron-proton and electron-proton elastic scattering cross sections. Read More


Ultra-low-background experiments address some of the most important open questions in particle physics, cosmology and astrophysics: the nature of dark matter, whether the neutrino is its own antiparticle, and does the proton decay. These rare event searches require well-understood and minimized backgrounds. Simulations are used to understand backgrounds caused by naturally occurring radioactivity in the rock and in every piece of shielding and detector material used in these experiments. Read More


Optical cavities provide high sensitivity to dispersion since their resonance frequencies depend on the index of refraction. We present a direct, broadband, and accurate measurement of the modes of a high finesse cavity using an optical frequency comb and a mechanical Fourier transform spectrometer with a kHz-level resolution. We characterize 16000 cavity modes spanning 16 THz of bandwidth in terms of center frequency, linewidth, and amplitude. Read More


Pulse coding is an effective method to overcome the trade-off between signal-to-noise ratio (SNR) and spatial resolution in optical-fiber sensing systems based on optical time-domain reflectometry (OTDR). However, the coding gain has not been yet fully exploited. We provide a comprehensive theoretical analysis and experimental validation of the sampling criteria for correlation-coded OTDR, showing that the coding gain can be further improved by harnessing the oversampling. Read More


We review instrumentation for nuclear magnetic resonance (NMR) in zero and ultra-low magnetic field (ZULF, below 0.1 $\mu$T) where detection is based on a low-cost, non-cryogenic, spin-exchange relaxation free (SERF) $^{87}$Rb atomic magnetometer. The typical sensitivity is 20-30 fT/Hz$^{1/2}$ for signal frequencies below 1 kHz and NMR linewidths range from Hz all the way down to tens of mHz. Read More


Providing a background discrimination tool is crucial for enhancing the sensitivity of next-generation experiments searching for neutrinoless double- beta decay. The development of high-sensitivity (< 20 eV RMS) cryogenic light detectors allows simultaneous read-out of the light and heat signals and enables background suppression through particle identification. The Cryogenic wide- Area Light Detector with Excellent Resolution (CALDER) R&D already proved the potential of this technique using the phonon-mediated Kinetic Inductance Detectors (KIDs) approach. Read More