https://www.cns.s.u-tokyo.ac.jp/~shimoura/research/nuc_data/pdf/19.pdf

Energy levels of light nuclei A=11☆

This work discusses a large-scale, coded-aperture imager for fast neutrons, building off a proof-of concept instrument developed at the U.S. Naval Research Laboratory (NRL). The Space Science Division at the NRL has a heritage of developing large-scale, mobile systems, using coded-aperture imaging, for long-range γ-ray detection and localization. The fast-neutron, coded-aperture imaging instrument, designed for a mobile unit (20 ft. ISO container), consists of a 32-element array of 15 cm � 15 cm � 15 cm liquid scintillation detectors (EJ-309) mounted behind a 12 � 12 pseudorandom coded aperture. The elements of the aperture are composed of 15 cm � 15 cm � 10 cm blocks of high-density polyethylene (HDPE). The arrangement of the aperture elements produces a shadow pattern on the detector array behind the mask. By measuring of the number of neutron counts per masked and unmasked detector, and with knowledge of the mask pattern, a source image can be deconvolved to obtain a 2-d location. The number of neutrons per detector was obtained by processing the fast signal from each PMT in flash digitizing electronics. Digital pulse shape discrimination (PSD) was performed to filter out the fastneutron signal from the γ background. The prototype instrument was tested at an indoor facility at the NRL with a 1.8-μCi and 13-μCi 252Cf neutron/γ source at three standoff distances of 9, 15 and 26 m (maximum allowed in the facility) over a 15-min integration time. The imaging and detection capabilities of the instrument were tested by moving the source in half- and one-pixel increments across the image plane. We show a representative sample of the results obtained at one-pixel increments for a standoff distance of 9 m. The 1.8-μCi source was not detected at the 26-m standoff. In order to increase the sensitivity of the instrument, we reduced the fastneutron background by shielding the top, sides and back of the detector array with 10-cm-thick HDPE. This shielding configuration led to a reduction in the background by a factor of 1.7 and thus allowed for the detection and localization of the 1.8 μCi. The detection significance for each source at different standoff distances will be discussed. Published by Elsevier B.V.

Nuclear Instruments and Methods in Physics Research A

Since 1999, the TRIUMF-ISAC facility has been providing rare isotope beams for nuclear physics experiments. The three pillars of the program are nuclear structure, nuclear astrophysics, and fundamental symmetries. This article reviews highlights of each of these aspects of the ISAC science program, including tests of the collective behaviors, first explained by Bohr, Mottelson and Rainwater, at the limits of nuclear stability, and future prospects with the ARIEL facility at TRIUMF.

https://iopscience.iop.org/article/10.1088/0031-8949/91/9/093002/pdf

The TRIUMF-ISAC facility: two decades of discovery with rare isotope beams

Classical nova explosions and type I X-ray bursts are the most frequent types of thermonuclear stellar explosions in the Galaxy. Both phenomena arise from thermonuclear ignition in the envelopes of accreting compact objects in close binary star systems. Detailed observations of these events have stimulated numerous studies in theoretical astrophysics and experimental nuclear physics. We discuss observational features of these phenomena and theoretical efforts to better understand the energy production and nucleosynthesis in these explosions. We also examine and summarize studies directed at identifying nuclear physics quantities with uncertainties that significantly affect model predictions.

Classical novae and type I X-ray bursts: challenges for the 21st century

An evaluation of A =1 8-19 was published in Nuclear Physics A595 (1995), p. 1. This version of A =1 9differs from the published version in that we have corrected some errors discovered after the article went to press. It has also been slightly revised as of June 13, 2000 to include hyperlinks for references and tables. Figures have been omitted from this manuscript. Also, Reference key numbers are in the NNDC/TUNL format.

Energy Levels of Light Nuclei A =1 9

Nous demontrons une preuve de faisabilite d'une methode de production d'intenses faisceaux (∼10 8 /s) d'ions radioactifs, differente de la technique standard ISOL (separation isotopique en ligne) en generant un faisceau de 11 C au laboratoire TRIUMF. Cette approche utilise les protons de 13 MeV produits par un cyclotron medical et devrait etre utile pour un domaine de radioisotopes interessant les chercheurs en astrophysique nucleaire.

/pdf/production-of-intense-radioactive-beams-at-isac-using-low-4b73tcqef8.pdf

Production of intense radioactive beams at ISAC using low-energy protons

Reduced uncertainty in the thermonuclear rate of the {sup 33}S(p,{gamma}){sup 34}Cl reaction would help to improve our understanding of nucleosynthesis in classical nova explosions. At present, models are generally in concordance with observations that nuclei up to roughly the calcium region may be produced in these explosive phenomena; better knowledge of this rate would help with the quantitative interpretation of nova observations over the S-Ca mass region, and contribute towards the firm establishment of a nucleosynthetic endpoint. As well, models find that the ejecta of nova explosions on massive oxygen-neon white dwarfs may contain as much as 150 times the solar abundance of {sup 33}S. This characteristic isotopic signature of a nova explosion could possibly be observed through the analysis of microscopic grains formed in the environment surrounding a nova and later embedded within primitive meteorites. An improved {sup 33}S(p,{gamma}){sup 34}Cl rate (the principal destruction mechanism for {sup 33}S in novae) would help to ensure a robust model prediction for the amount of {sup 33}S that may be produced. Finally, constraining this rate could confirm or rule out the decay of an isomeric state of {sup 34}Cl(E{sub x} = 146 keV, t{sub 1/2} = 32 m) as a source formore » observable gamma-rays from novae. We have performed several complementary experiments dedicated to improving our knowledge of the {sup 33}S(p,{gamma}){sup 34}Cl rate, using both indirect methods (measurement of the {sup 34}S({sup 3}He,t){sup 34}Cl and {sup 33}S({sup 3}He,d){sup 34}Cl reactions with the Munich Q3D spectrograph) and direct methods (in normal kinematics at CENPA, University of Washington, and in inverse kinematics with the DRAGON recoil mass separator at TRIUMF). Our results will be used with nova models to facilitate comparisons of model predictions with present and future nova observables.« less

Improving the 33S(p,γ)34Cl reaction rate for models of classical nova explosions

The ${}^{33}$S($p,\ensuremath{\gamma}$)${}^{34}$Cl reaction is important for constraining predictions of certain isotopic abundances in oxygen-neon novae. Models currently predict as much as 150 times the solar abundance of ${}^{33}$S in oxygen-neon nova ejecta. This overproduction factor may vary by orders of magnitude due to uncertainties in the ${}^{33}$S($p,\ensuremath{\gamma}$)${}^{34}$Cl reaction rate at nova peak temperatures. Depending on this rate, ${}^{33}$S could potentially be used as a diagnostic tool for classifying certain types of presolar grains. Better knowledge of the ${}^{33}$S($p,\ensuremath{\gamma}$)${}^{34}$Cl rate would also aid in interpreting nova observations over the S-Ca mass region and contribute to the firm establishment of the maximum endpoint of nova nucleosynthesis. Additionally, the total S elemental abundance which is affected by this reaction has been proposed as a thermometer to study the peak temperatures of novae. Previously, the ${}^{33}$S($p,\ensuremath{\gamma}$)${}^{34}$Cl reaction rate had only been studied directly down to resonance energies of 432 keV. However, for nova peak temperatures of $0.2--0.4$ GK there are seven known states in ${}^{34}$Cl both below the 432-keV resonance and within the Gamow window that could play a dominant role. Direct measurements of the resonance strengths of these states were performed using the DRAGON (Detector of Recoils And Gammas of Nuclear reactions) recoil separator at TRIUMF. Additionally two new states within this energy region are reported. Several hydrodynamic simulations have been performed, using all available experimental information for the ${}^{33}$S($p,\ensuremath{\gamma}$)${}^{34}$Cl rate, to explore the impact of the remaining uncertainty in this rate on nucleosynthesis in nova explosions. These calculations give a range of $\ensuremath{\approx}$20--150 for the expected ${}^{33}$S overproduction factor, and a range of $\ensuremath{\approx}$100--450 for the ${}^{32}$S/${}^{33}$S ratio expected in ONe novae.

pdf/constraining-nova-observables-direct-measurements-of-nvtnvf2l6a.pdf

Constraining nova observables: direct measurements of resonance strengths in 33S(p,\gamma)34Cl

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

B. Guo

Author Tools

Chat about Author

Papers

Production of intense radioactive beams at ISAC using low-energy protons

Improving the 33S(p,γ)34Cl reaction rate for models of classical nova explosions

Constraining nova observables: direct measurements of resonance strengths in 33S(p,\gamma)34Cl