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At least 883 records · Page 49

LLNL International Working Group on Gamma Spectrometry - Preparation of IDB Dataset [Slides]

The spectral information and associated metadata, including source information, detector setup, and shielding configuration is described in human readable, comma-separated text files (csv). Six csv files are associated with each material type and include the following information (where [Isotope] is U, Pu, and MOX): [Isotope]_measurement_metadata Metadata of the measurement configuration, including material composition at time of acquisition (decay corrected from certificate date). Data that is unique to a measurement configuration e.g. detector geometry, source-detector distance, analyzer and other electronics used, attenuating materials are provided in this file. [Isotope]_spectrum_metadata The information that is unique to the spectrum. This includes detector specifications (e.g. date of acquisition, number of channels, gain (keV/channel), energy range, real and live time, full width half-maximum (FWHM) of the 186 or 208 peak for uranium or plutonium measurements, respectively. [Isotope]_source_metadata The source material used for the measurement, this includes the ratio and uncertainties of isotopes present and processing information of the material. In addition, the certificate information for the source material is listed. [Isotope]_spectrum_counts_metadata The counts per channel for each spectrum. This data is linked via the UID.spectrum index to the measurement_metadata file. [Isotope]_spectrum_checksum_metadata The MD5 checksum for the original spectrum file. This data is linked via the UID.spectrum index to the measurement_metadata file. This information is provided to prevent duplication of entries in the database. [Isotope]_provenance Details on the csv data provider, including laboratory and contract information.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

CHARGED-CURRENT DOUBLE-DIFFERENTIAL CROSS SECTION MEASUREMENT OF ELECTRON NEUTRINOS IN LOW RECOIL REGION ON HYDROCARBON AT ∼7 GEV

Measuring neutrino mixing angles, especially the CP violation phase and mass hierarchy, is one of the priorities of the neutrino community and long baseline neutrino oscillation programs, such as T2K and NOvA, provided the most precise measurements to date. One of the dominating uncertainties of the measurements is the neutrino interaction model due to the difficulty of modeling the nuclear effects from first principles. As a result, neutrino scattering experiments such as MINERvA were conducted to provide data as input to reduce this uncertainty. This thesis presents a charged-current double-differential cross section measurement of electron neutrinos using the MINERvA detector in terms of available energy (a proxy of energy transfer), three-momentum transfer, and/or transverse momentum of the final state electron. This measurement focuses on the transition region between quasi-elastic and resonance processes, where the multi-nucleon knockout process dominates. The result is compared to a modified GENIE model and similar measurements using muon neutrino samples. In addition, this measurement reproduces the photon-like excess seen by previous MINERvA electron neutrino measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Correlative Aspects of the Solar Electron Neutrino Flux and Solar Activity

Between 1970 and 1994, the Homestake Solar Neutrino Detector obtained 108 observations of the solar electron neutrino flux (less than 0.814 MeV). The "best fit" values derived from these observations suggest an average daily production rate of about 0.485 Ar-37 atom per day, a rate equivalent to about 2.6 SNU (solar neutrino units) or about a factor of 3 below the expected rate from the standard solar model. In order to explain, at least, a portion of this discrepancy, some researchers have speculated that the flux of solar neutrinos is variable, possibly being correlated with various markers of the solar cycle (e.g., sunspot number, the Ap index, etc.). In this paper, using the larger "standard data set," the issue of correlative behavior between solar electron neutrino flux and solar activity is re-examined. The results presented here clearly indicate that no statistically significant association exists between any of the usual markers of solar activity and the solar electron neutrino flux.

Wilson, Robert M.↗

Detector Control and Data Acquisition for the Wide-Field Infrared Survey Telescope (WFIRST) with a Custom ASIC

The Wide-Field Infrared Survey Telescope (WFIRST) will have the largest near-IR focal plane ever flown by NASA, a total of 18 4K x 4K devices. The project has adopted a system-level approach to detector control and data acquisition where 1) control and processing intelligence is pushed into components closer to the detector to maximize signal integrity, 2) functions are performed at the highest allowable temperatures, and 3) the electronics are designed to ensure that the intrinsic detector noise is the limiting factor for system performance. For WFIRST, the detector arrays operate at 90 to 100 K, the detector control and data acquisition functions are performed by a custom ASIC at 150 to 180 K, and the main data processing electronics are at the ambient temperature of the spacecraft, notionally approx.300 K. The new ASIC is the main interface between the cryogenic detectors and the warm instrument electronics. Its single-chip design provides basic clocking for most types of hybrid detectors with CMOS ROICs. It includes a flexible but simple-to-program sequencer, with the option of microprocessor control for more elaborate readout schemes that may be data-dependent. All analog biases, digital clocks, and analog-to-digital conversion functions are incorporated and are connected to the nearby detectors with a short cable that can provide thermal isolation. The interface to the warm electronics is simple and robust through multiple LVDS channels. It also includes features that support parallel operation of multiple ASICs to control detectors that may have more capability or requirements than can be supported by a single chip.

data acquisition↗

A new measurement of the cosmic ray electron spectrum from 10 GeV to 300 GeV

The spectrum of cosmic-ray electrons has been measured with an instrument that combines a transition-radiation detector with a shower detector. The transition-radiation detector provides unique identification of individual electrons and good discrimination against protons. At the same time, it allows the construction of a large-area instrument (0.48 sq m ? ster) and consequently makes possible a measurement of improved statistical accuracy. The instrument has been calibrated with electron beams of 5-300 GeV at Fermilab, thus eliminating energy-dependent biases. A first balloon flight yielded 30 hours of data at an altitude of 5 g/sq cm. The design of the instrument is described, along with the accelerator calibrations and the analysis of the balloon flight data. The spectrum of electrons is found to be significantly steeper than that of protons over the whole energy range.

Hartmann, G.↗

The hidden ion population of the magnetosphere

The presence of a cold ion population in the magnetosphere which is normally hidden from particle detector observation by the positive charging of the spacecraft is reported. Ion and electron data were obtained from particle detectors on the ATS 6 and SCATHA satellites designed to measure the 1-eV to 80-keV plasma population. The cold, isotropic ion population, with temperature 1 eV and density 10-100/cu cm, was detected only when the spacecraft were in eclipse, when spacecraft potential had dropped from +10 V in sunlight to +4 to +5 V. The hidden ion population was found at geosynchronous altitude only during geomagnetically quiet times and when there has been an absence of geomagnetic activity for several hours, and appears to coexist with the plasma sheet. More consistent measurements of the cold ion population at midnight or at other local times would require the biasing of the ion detector with respect to the spacecraft, or the controlling of spacecraft potential.

Olsen, R. C.↗

Experimenter's data package for the descending layers rocket

In response to a proposal from Science Applications International Corporation (SAIC), NASA Headquarters has approved a sounding rocket mission designed to study the physics of intermediate layers in the Earth's ionosphere at middle latitudes. The experiment will be carried out by a team of scientists and engineers from the NASA Wallops Flight Facility, SAIC, the NASA Goddard Space Flight Center, and the Millstone Hill radar observatory. The mission will involve the launch of an instrumented sounding rocket from the Wallops Island rocket range in the summer of 1994, with the objective of penetrating a descending ionized layer in the E-region between altitudes of 115 and 140 km. Instrumentation aboard the rocket will measure the ion and neutral composition of the layer, its plasma density, driving wind and electric field forces, the thermal ion distribution function, and electron temperature. Depending on payload weight constraints and subject to availability, a particle detector to measure energetic ion and/or electron fluxes near the layer may also be included. This document was prepared as a reference for the NASA payload development and experiment teams, for distribution at the Project Initiation Conference (PIC). The design specifications discussed herein are therefore of a preliminary nature; the intent is to promote open discussions between experimenters and NASA engineers that will lead to a final design capable of achieving the experiment objectives.

Earle, Greg↗

Materials for Gamma Radiation Sensors

Sensors used for spectroscopic measurements of gamma radiation are most often scintillator or semiconductor materials. An overview is provided in this chapter on the materials and development techniques used in producing spectroscopic gamma radiation sensors. Challenges that prevent a perfect sensor are discussed along with the reasons why some sensor materials are ubiquitous despite their performance limitations. The types of sensors commonly used as detectors are discussed along with their key physical properties and electronic characteristics. Materials commonly utilized in radiation detectors are then reviewed to highlight how sensor materials have advanced since the earliest gamma detectors were developed

Johns, Paul M.↗

Ionization Yield in Silicon for eV-Scale Electron-Recoil Processes

The development of single charge resolving, macroscopic silicon detectors has opened a window into rare processes at the O(eV) scale. In order to reconstruct the energy of a given event, or model the charge signal obtained for a given amount of energy absorbed by the electrons in a detector, an accurate charge yield model is needed. In this paper we review existing measurements of charge yield in Silicon, focusing in particular on the region below 1 keV. We highlight a calibration gap between 12-50 eV (referred to as the "UV-gap") and employ a phenomenological model of impact ionization to explore the likely charge yield in this energy regime. Finally, we explore the impact of variations in this model on a test case, that of dark matter scattering off electrons, to illustrate the scientific impact of uncertainties in charge yield.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

μRWELL detector developments at Jefferson Lab for high luminosity experiments

One of the future plans at Jefferson Lab is running electron scattering experiments with large acceptance detectors at luminosities > 10^37 cm^−2 s^−1. These experiments allow the measurements of the Double Deeply Virtual Compton Scattering (DDVCS) reaction, an important physics process in the formalism of Generalized Parton Distributions, which has never been measured because of its small cross-section. The luminosity upgrade of CLAS12 or the SOLID detector makes Jefferson Lab a unique place to measure DDVCS. One of the important components of these high luminosity detectors is a tracking system that can withstand high rates of ≈ 1MHz/cm2. The recently developed Micro-Resistive Well (𝜇RWELL) detector technology is a promising option for such a tracking detector by combining good position resolutions, low material budget with simple mechanical construction, and low production costs. In this proceeding, we will discuss recent developments and studies with 𝜇RWELL detectors at Jefferson Lab for future upgrades of the CLAS12 detector to study the DDVCS reaction.

Hauenstein, Florian↗

First study of the nuclear response to fast hadrons via angular correlations between pions and slow protons in electron-nucleus scattering

We report on the first measurement of angular correlations between high-energy pions and slow protons in electron-nucleus (eA) scattering, providing a new probe of how a nucleus responds to a fast-moving quark. The experiment employed the CLAS detector with a 5-GeV electron beam incident on deuterium, carbon, iron, and lead targets. For heavier nuclei, the pion-proton correlation function is more spread-out in azimuth than for lighter ones, and this effect is more pronounced in the πp channel than in earlier ππ studies. The proton-to-pion yield ratio likewise rises with nuclear mass, although the increase appears to saturate for the heaviest targets. These trends are qualitatively reproduced by state-of-the-art eA event generators, including BeAGLE, eHIJING, and GiBUU, indicating that current descriptions of target fragmentation rest on sound theoretical footing. At the same time, the precision of our data exposes model-dependent discrepancies, delineating a clear path for future improvements in the treatment of cold-nuclear matter effects in eA scattering.

Correlations↗

Movable Thermometer System in ProtoDUNE

The movable temperature profiler is a 7 m vertical array of 24 sensors that measures cryogenic temperatures with a precision of a few mK. This precision is necessary to monitor the efficiency of re-circulation and purification of liquid-argon inside large liquid-argon based neutrino detectors. Liquid argon temperature impacts electron (signal) drift velocity, flow, purity distribution and thus the overall energy calibration. The temperature profiler is motorized and moves vertically, while in the detector, and cross-calibrates neighboring sensors. The temperature offsets between each sensor cancel the effects of electromagnetic noise. This poster reports on the temperature measurements and such in-situ cross-calibrations at ProtoDUNE (single phase) at CERN.}

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Measurement of inclusive electrons from open heavy-flavor hadron decays in p + p collisions at s = 200 GeV with the STAR detector

We report a new measurement of the production cross section for inclusive electrons from open heavy-flavor hadron decays as a function of transverse momentum (p T ) at midrapidity (|y| < 0.7) in p + p collisions at √s = 200 GeV. Overall, the result is presented for 2.5 < P T < 10 GeV/c with an improved precision above 6 GeV/c with respect to the previous measurements, providing more constraints on perturbative QCD calculations. Moreover, this measurement also provides a high-precision reference for measurements of nuclear modification factors for inclusive electrons from open-charm and -bottom hadron decays in heavy-ion collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Method and apparatus for radiometer star sensing

A method and apparatus for determining the orientation of the optical axis of radiometer instruments mounted on a satellite involves a star sensing technique. The technique makes use of a servo system to orient the scan mirror of the radiometer into the path of a sufficiently bright star such that motion of the satellite will cause the star's light to impinge on the scan mirror and then the visible light detectors of the radiometer. The light impinging on the detectors is converted to an electronic signal whereby, knowing the position of the star relative to appropriate earth coordinates and the time of transition of the star image through the detector array, the orientation of the optical axis of the instrument relative to earth coordinates can be accurately determined.

Wilcox, Jack E.↗

First Measurement of the Flux-Averaged Differential Charged-Current Electron-Neutrino and Antineutrino Cross Section on Argon with the MicroBooNE Detector

The MicroBooNE experiment uses a liquid argon time projection chamber (LArTPC) located at Fermilab, Chicago. MicroBooNE is able to detect neutrinos from two accelerators: on-axis from the Booster Neutrino Beam (BNB) and off-axis from the Neutrinos at the Main Injector (NuMI). While one of the primary objectives of the MicroBooNE experiment is to search for short-baseline neutrino oscillations using the BNB, it also has a rich program of R\&D, neutrino-argon cross section measurements and beyond the standard model searches. This thesis presents a detailed study of the off-axis neutrino flux from the NuMI beam at MicroBooNE as well as measurements of the charged current flux-averaged total and differential electron neutrino and antineutrino cross section on argon using this beam. The data used in these measurements was taken during the first year of MicroBooNE running while the NuMI beam was in forward horn current mode. These are the first high statistics measurement s of ele ctron neutrino argon interactions and include the first measurement of this cross section as a function of the outgoing electron energy and with full angular coverage. The measurement is compared to the GENIE and NuWro generators and shows consistency with both.

Mistry, Krishan Jitesh↗

Cardiac R-wave detector with automatic sensitivity control

An electronic circuit that automatically changes its sensitivity was developed for detecting the bioelectric signal resulting from activation of the heart's ventricles. Regulation of sensitivity was accomplished with two feedback channels that maintain the sensitivity level between an upper and a lower limit. These limits are proportional to the R-wave amplitude. Tests on an experimental circuit demonstrated a capability to reject unwanted signal noise, illustrated difficulties encountered without sensitivity control, and presented closed loop transients which occurred for step changes in R-wave amplitude.

Gebben, V. D.↗

Nonscanning climate sensor study

The Nonscanning Climate Sensor represents a new instrument for climate research and global monitoring of the earth radiation budget. It contains a mosaic of array of detectors which measures the outgoing radiation of the earth in all directions without the need for mechanical scanning. The goal is to eliminate all moving parts and obtain highly calibrated measurements for up to one solar cycle (11 years) without being susceptible to mechanical failure. Over set intervals of time, the angular measurements are integrated up to produce total reflected and emitted flux values from each target area on the Earth. To achieve the require sensitivity while maintaining a flat spectral response, an improved dual cavity detector with digital control loop was developed. The detector is self calibrating to maintain high precision over the life of the instrument. Prototype detectors and a complete set of electronics with a microprocessor controller were fabricated and tested. Measurements show that the new detectors are more than an order of magnitude more sensitive than previous versions.

Hoffman, James W.↗

High energy primary electron spectrum observed by the emulsion chamber

A detector of the emulsion chamber type is used to measure the energy spectrum of cosmic-ray electrons. Two large emulsion chambers, each having an area of 40 by 50 sq cm, are exposed for about 25.5 hr at an average pressure altitude of 3.9 mbar. About 500 high-energy cascades (no less than about 600 GeV) are detected by searching for dark spots on the X-ray films. A power-law energy dependence formula is derived for the spectrum of primary cosmic-ray electrons in the energy region over 100 GeV. The results are in good agreement with the transition curves obtained previously by theoretical and Monte Carlo calculations.

Nishimura, J.↗