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All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

The BiPo detector for ultralow radioactivity measurements

The development of BiPo detectors is dedicated to the measurement of extremely high radiopurity in {sup 208}Tl and {sup 214}Bi for the SuperNEMO double beta decay source foils. A modular prototype called BiPo-1 with 0.8 m{sup 2} of sensitive surface area has been running in the Modane Underground Laboratory since February 2008. The goal of BiPo-1 is to measure the different components of the background and in particular the surface radiopurity of the plastic scintillators that make up the detector. The first phase of data collection has been dedicated to the measurement of the radiopurity in {sup 208}Tl. After more than one year of background measurement a surface activity of the scintillators of A({sup 208}Tl) = 1.5 {mu}Bq/m{sup 2} is reported here.Given this level of background, a larger BiPo3 detector having 3.25 m{sup 2} of active surface area, will able to qualify the radiopurity of the SuperNEMO selenium double beta decay foils with the required sensitivity of A({sup 208}Tl)<3-4 {mu}Bq/kg(90% C.L.) with a six month measurement. This detector is actually under construction and will be installed in the Canfranc Underground Laboratory mid 2011.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Low radioactivity CaF{sub 2} scintillator crystals for CANDLES

CANDLES is the project to search for neutrinoless double beta (0{nu}{beta}{beta}) decay of {sup 48}Ca by using CaF{sub 2} scintillators. The observation of 0{nu}{beta}{beta} decay will prove the existence of massive Majorana neutrinos. Expected performances and current status of the CANDLES system are described.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Multi-Channel Integrated Circuits For Use In Research With Radioactive Ion Beams

The Integrated Circuits Design Research Laboratory at Southern Illinois University Edwardsville (SIUE) has been collaborating over the past several years with the Nuclear Reactions Group at Washington University (WU) on the development of a family of custom, multi-channel Integrated Circuits (ICs). To date, the collaboration has successfully produced two micro-chips. The first was an analog shaped and peak sensing chip known as HINP16C (Heavy Ion Nuclear Physics--16 Channel). The second chip, christened PSD8C (Pulse Shape Discrimination--8 Channel), was designed to logically complement (in terms of detector types) the HINP16C chip. The HINP16C chip, for use with solid-state detectors, produces sparsified analog pulse trains for both linear (pulse height) and timing (relative to an external reference) signals. A shaper and peak detector are implemented in the linear branch, and a pseudo Constant-Fraction Discriminator (CFD) and Time-to-Voltage Converter (TVC) are implemented in the logic/timing branch. The internal and external gain options make the chip suitable for use in a wide variety of applications. PSD8C greatly simplifies the pulse-processing electronics needed for large arrays of scintillation detectors. As the PSD8C employs user-controlled, multi-region charge integration, particle identification is inherent in the design. Each of the three pulse-height sub-channels consists of a gated integrator with eight programmable charging rates and an externally programmable gate generator that defines the start (with 4 time ranges) and the width (with 4 time ranges) of the gate, relative to an external discriminator signal. Moreover, each channel on the chip also contains a TVC. This paper describes the design, capabilities, and features of the HINP16C and PSD8C ICs along with a description of how the chips are being used. It also discusses modifications and enhancements which have been made to both chips and their associated prototypical systems in order to improve ease of use and increase performance.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Measurement of natural radioactivity and assessment of radiation hazard indices in soil samples at Pengerang, Kota Tinggi, Johor

Pengerang area consists of a mix of private plantation, individual residential lots and state land, which is leased for agriculture related activities. The analysis was conducted to determine the specific activity of the initial value and the radiation hazard indices in the surrounding area in Pengerang. This area will be developed into a major downstream for oil and gas. The aims of this preliminary study were 1) to determine the specific activities of {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 40}K of soil samples at six selected areas by Gamma-ray spectrometry and 2) to calculate the radiation hazard indices. The specific activities (Bq/kg) of the samples ranged from 7.08±5.01 to 36.29±25.72 Bq/kg, 5.62±3.98 to 34.53±24.07 Bq/kg, 4.75±3.42 to 24.76±17.66 Bq/kg and 10.58±7.51 to 101.25±72.00 Bq/kg for {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 40}K, respectively. These values were well within the range that reported by UNSCEAR. The study also examined the radiation hazard indices, the mean values obtained were 48.49±28.06 Bq/kg for Radium Equivalent Activity (Raeq), 0.34 Bq/kg for Representative Level Index (I{sub γ}), 21.83 nGy/h for Absorbed dose rates (D), 0.27 mSv/y for Annual Effective Dose Rates (Deff), 0.13 and 0.18 for External Hazards Index (H{sub ex}) and Internal Hazard Index (H{sub in}), respectively. These calculated hazard indices were used to estimate the potential radiological health risk in soil and the dose rates associated with it were well below their permissible limit. The overall findings show that no radiological threat to the health of the population in the study area.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Effectiveness of mineral soil to adsorb the natural occurring radioactive material (norm), uranium and thorium

A study has been performed on U-soil and Th-soil adsorption of three types of soil collected from Selangor State of Malaysia which are Saujana Putra, Bukit Changgang and Jenderam Hilir. In this study, natural radionuclide (U and Th) soil adsorption based on batch experiments with various initial concentrations of the radionuclide elements were carried out. Parameters that were set constant include pH at 5;amount of soil used was 5 g each, contact time was 24 hour and different initial concentration for each solution of U and Th which is 5 mg/L, 10 mg/L, 15 mg/L, 20 mg/L, 25 mg/L and 40 mg/L were used. The K{sub d} values for each type of soil were determined in this batch experiments which was based on US-EPA method, in order to estimate adsorption capacity of the soil.The K{sub d} values of Th found higher than Kd values of U for all of the soil samples, and the highest was found on the soil collected from Bukit Changgang. The soil clay content was one of factors to influence the adsorption of both U and Th from dilute initial solution. The U-soil and Th-soil adsorption process for all the soil samples studied are generally obeying unimolecular layer Langmuir isotherm model. From Langmuir isotherm, the maximum adsorption capacity for U was 0.393mg/g and for Th was 1.53 mg/g for the soil that was taken from Bukit Changgang. From the study, it suggested that the soil from Bukit Changgang applicable as potential enhanced barrier for site disposing waste containing U and Th.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Assessment of natural radioactivity concentrations and gamma dose levels around Shorapur, Karnataka

This study assesses the level of background radiation around Shorapur. The study region locates the western part of the Yadgir district of Karnataka. Shorapur and Shahapur talukas are mostly composed of clay, shale sandstone, granite rock and part of study area is black soil. Thirty sample locations were selected along the length and breadth of Shorapur and Shahapur taluka. Natural radionuclide activity concentrations in soil samples were determined using 4'X4' NaI (Tl) gamma spectroscopy. Outdoor gamma dose measurements in air at 1 m above ground level were determined using Rad Eye PRD survey meter. Estimated dose values are compared with the survey meter values and found to be good agreement between them and also with the data obtained from different other areas of Karnataka and India. The average values were found to be slightly higher in the present investigation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Transportation of a radioactive ion beam for precise laser-trapping experiments

Francium is the heaviest species among the alkali elements. Due to its properties, francium is said to be of advantage in measurements of tiny observations, such as atomic parity violation and electric dipole moment. Before executing experiments with francium, it must be produced artificially because it is one of the most unstable elements. We produced francium with the nuclear fusion reaction of an oxygen beam and gold target, ionized the produced francium through a thermal ionization process, and extracted the ion with electrostatic fields. However, the thermal ionization process is known to ionize not only an objective atom but also other atomic species. Therefore, a Wien filter was installed to analyze the composition of the ion beam and purify the beam. This allowed us to improve the beam purity from ∼10{sup −6} to ∼10{sup −3}.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Aqueous harvesting of 88 Zr at a radioactive-ion-beam facility for cross-section measurements

Isotope harvesting is a method of collecting the long-lived radioisotopes that build up during the operation of ion-beam facilities in a way that is useful for subsequent research. As a demonstration of this method for the collection of a group IV metal at a fragmentation facility, the high-energy Zr 88 secondary beam produced from a 140-MeV/u Mo 92 primary beam at the National Superconducting Cyclotron Laboratory (NSCL) was stopped in a water target. The setup aimed to mimic the aqueous beam dump that will be implemented at the Facility for Rare Isotope Beams (FRIB). The collected Zr 88 and accompanying Y 88 decay daughter were radiochemically extracted from the solution and made into target samples suitable for neutron-capture cross-section measurements. These samples were then irradiated at two reactor facilities, and the Zr 88 average thermal-neutron-capture cross section ( σ T ) and resonance integral ( I ) were determined to be σ T = ( 8.04 ± 0.63 ) × 10 5 b and I = ( 2.53 ± 0.28 ) × 10 6 b. The σ T value agrees well with previous results and I , determined for the first time here, was found to be the largest measured resonance integral by two orders of magnitude. The Y 88 thermal-neutron-capture cross section was determined to be less than 1.8 × 10 4 b. This work demonstrates the steps needed to make cross-section measurements with samples produced via aqueous isotope harvesting.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2015

Study of the feasibility of distributed cathodic arc as a plasma source for development of the technology for plasma separation of SNF and radioactive wastes

One of the key problems in the development of plasma separation technology is designing a plasma source which uses condensed spent nuclear fuel (SNF) or nuclear wastes as a raw material. This paper covers the experimental study of the evaporation and ionization of model materials (gadolinium, niobium oxide, and titanium oxide). For these purposes, a vacuum arc with a heated cathode on the studied material was initiated and its parameters in different regimes were studied. During the experiment, the cathode temperature, arc current, arc voltage, and plasma radiation spectra were measured, and also probe measurements were carried out. It was found that the increase in the cathode heating power leads to the decrease in the arc voltage (to 3 V). This fact makes it possible to reduce the electron energy and achieve singly ionized plasma with a high degree of ionization to fulfill one of the requirements for plasma separation of SNF. This finding is supported by the analysis of the plasma radiation spectrum and the results of the probe diagnostics.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

RF deflecting cavity for fast radioactive ion beams

Abstract The Facility for Rare Isotope Beams (FRIB) will be a new scientific user facility that produces rare-isotope beams for experiments from the fragmentation of heavy ions at energies of 100–200 MeV/u. During the projectile fragmentation, the rare isotope of interest is produced along with many contaminants that need to be removed before the beam reaches detectors. At FRIB, this is accomplished with a magnetic projectile fragment separator. However, to achieve higher beam purity, in particular for proton-rich rare isotopes, additional purification is necessary. RadiaBeam in collaboration with Michigan State University (MSU) has designed a 20.125 MHz radiofrequency (RF) fragment separator capable of producing a 4 MV kick with 18 cm aperture in order to remove contaminant isotopes based on their time of flight. In this paper, we will discuss the RF and engineering design considerations of this separator cavity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Electron Emission From Slightly Oxidized Delta-stabilized Plutonium Generated by its Radioactivity, and Radiation Induced Ionization and Dissociation of Hydrogen at its Surface

Energy dependent electron emission between zero and 1.4 keV generated by the natural reactivity of plutonium was measured by an electrostatic spectrometer with known acceptance angle and acceptance area. The electron spectral intensity decreases continuously except for a distinctive feature of unknown origin at approximately 180eV. The spectrum was converted to energy dependent electron flux (e/cm 2 } s) using the assumption that the emission has a cosine angular distribution. The energy dependent electron mean free path in gases and literature cross sections for electron induced reactions were used to determine the number of ionization and dissociation reactions per cm 2 second, found to be about 8*10 8 /cm 2 s and 1.5*10 8 /cm 2 s, respectively, for hydrogen. These results are to be used with caution until complementary measurements can be made, e.g. independent measurement of the total emitted electron current, since the results here are based on the assumption that the electron emission has a cosine angular distribution. That is unlikely to be correct.

08 HYDROGEN↗
DOE OSTI2011

Electron Emission from Slightly Oxidized Depleted Uranium Generated by its Own Radioactivity Measured by Electron Spectroscopy, and Electron-Induced Dissociation and Ionization of Hydrogen Near its Surface.

Energy dependent electron emission (counts per second) between zero and 1.4 keV generated by the natural reactivity of uranium was measured by an electrostatic spectrometer with known acceptance angle and acceptance area. The electron intensity decreases continuously with energy, but at different rates in different energy regimes, suggesting that a variety of processes may be involved in producing the observed electron emission. The spectrum was converted to energy dependent electron flux (e-/cm 2 s) using the assumption that the emission has a cosine angular distribution. The flux decreased rapidly from ~10 6 /cm 2 s to ~10 5 /cm 2 s in the energy range from zero to 200 eV, and then more slowly from ~10 5 /cm 2 s to ~3*10 4 /cm 2 s in the range from 200 to 1400 eV. The energy dependent electron mean free path in gases together with literature cross sections for electron induced reactions were used to determine the number of ionization and dissociation reactions per cm 2 s within the inelastic mean free path of electrons, and found to be about 1.3*10 8 /cm 2 s and 1.5*10 7 /cm 2 s, respectively, for hydrogen. An estimate of the number of ionization and dissociation reactions occurring within the total range, rather than the mean free path of electrons in gases resulted in 6.2*10 9 /cm 2 s and 1.3*10 9 /cm 2 s, respectively. The total energy flux carried by electrons from the surface is suspiciously close to the total possible energy generated by one gram of uranium. A likely source of error is the assumption that the electron emission has a cosine distribution. Angular distribution measurements of the electron emission would check that assumption, and actual measurement of the total current emanating from the surface are needed to confirm the value of the current calculated in section II. These results must therefore be used with caution - until they are confirmed by other measurements.

08 HYDROGEN↗
DOE OSTI2012

Monitoring Potential Transport of Radioactive Contaminants in Shallow Ephemeral Channels

The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA), Nevada Site Office (NSO), Environmental Restoration Soils Activity has authorized the Desert Research Institute (DRI) to conduct field assessments of potential sediment transport of contaminated soil from Corrective Action Unit (CAU) 550, Area 8 Smoky Contamination Area (CA), during precipitation runoff events. CAU 550 includes Corrective Action Sites (CASs) 08-23-03, 08-23-04, 08-23-06, and 08-23-07; these CASs are associated with tests designated Ceres, Smoky, Oberon, and Titania, respectively.

(CAU)↗
DOE OSTI2015

Nuclear physics with radioactive ion beams

This is a final report on DOE Grant No. DE FG02 96ER40955, which was active at Tennessee Technological University (TTU) from 1 March 1996 to 29 May 2015. Generally, this report will provide an overall summary of the more detailed activities presented in the progress reports, numbered DOE/ER/40955-1 through DOE/ER/40955-18, which were submitted annually to the DOE Office of Nuclear Physics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

NSR&D Program Fiscal Year 2015 Funded Research Stochastic Modeling of Radioactive Material Releases Final Report

Nonreactor nuclear facilities operating under the approval authority of the U.S. Department of Energy use unmitigated hazard evaluations to determine if potential radiological doses associated with design basis events challenge or exceed dose evaluation guidelines. Unmitigated design basis events that sufficiently challenge dose evaluation guidelines or exceed the guidelines for members of the public or workers, merit selection of safety structures, systems, or components or other controls to prevent or mitigate the hazard. Idaho State University, in collaboration with Idaho National Laboratory, has developed a portable and simple to use software application called SODA (Stochastic Objective Decision-Aide) that stochastically calculates the radiation dose distribution associated with hypothetical radiological material release scenarios. Rather than producing a point estimate of the dose, SODA produces a dose distribution result to allow a deeper understanding of the dose potential. SODA allows users to select the distribution type and parameter values for all of the input variables used to perform the dose calculation. Users can also specify custom distributions through a user defined distribution option. SODA then randomly samples each distribution input variable and calculates the overall resulting dose distribution. In cases where an input variable distribution is unknown, a traditional single point value can be used. SODA, developed using the MATLAB coding framework, has a graphical user interface and can be installed on both Windows and Mac computers. SODA is a standalone software application and does not require MATLAB to function. SODA provides improved risk understanding leading to better informed decision making associated with establishing nuclear facility material-at-risk limits and safety structure, system, or component selection. It is important to note that SODA does not replace or compete with codes such as MACCS or RSAC; rather it is viewed as an easy to use supplemental tool to help improve risk understanding and support better informed decisions. The SODA development project was funded through a grant from the DOE Nuclear Safety Research and Development Program.

42 ENGINEERING↗
DOE OSTI2020

Estimating a protection factor from homemade facemasks for Los Alamos radioactive aerosols

The Los Alamos National Laboratory has required usage of facemasks “whenever interacting with or near others." The present document estimates the respiratory protection factor of homemade facemasks to be 1.4 and 1.2 for aerosol particles, below and above 0.3 μm diameter, respectively. This includes an estimated leakage of 70% and 52% for aerosol particles below and above 0.3 μm diameter, respectively.

61 RADIATION PROTECTION AND DOSIMETRY↗