Decay of 134Cs

1968 ◽  
Vol 46 (23) ◽  
pp. 2579-2587 ◽  
Author(s):  
T. S. Nagpal
Keyword(s):  
Gamma Ray ◽  
Line Spectrum ◽  
Conversion Line ◽  
Theoretical Predictions ◽  
First Time

The gamma ray spectrum and the conversion line spectrum of 134Cs have been investigated using lithium-drifted detectors. The 563–569 and 796–802 keV doublets have been completely resolved for the first time. The energies in keV, relative intensities in percent per disintegration, and dominant multipolarities of the transitions observed are: 475.57(1.6%, E2); 563.06(8.6%, E2); 569.30(13.3 %, M1); 604.83(97.5%, E2); 796.02(87.0%, E2); 801.90(7.9%, E2); 1038.19(1%, M1 + E2); 1168.40(2%, E2); 1365.40(3.5%, E2); and 1580(0.03%, M1 or E2). The present results are consistent with the levels in 134Ba at 0(0+), 605(2+), 1168(2+), 1401(4+), 1580([Formula: see text]), 1643(3+), and 1970(4+) keV. There is no evidence for the previously reported levels at 923, 1062, 1374, 1770, and 1854 keV. The intensity of the beta-feeds to the levels at 1970, 1643, 1580, and 1401 keV respectively are 24.7%, 1.6%, 0.03%, and 73.7%, as computed from the intensity balance of levels in 134Ba. A modest attempt at comparison between the observed excited levels and theoretical predictions is made.

scholarly journals Integrated Cross Sections of the Photo-Neutron Reactions Induced on \(^{197}\)Au with 60 \(\text{MeV}\) Bremsstrahlung

2020 ◽  
Vol 30 (1) ◽  
pp. 49
Author(s):  
Nguyen Van Do ◽  
Nguyen Thanh Luan ◽  
Nguyen Thi Xuan ◽  
Pham Duc Khue ◽  
Kim Tien Thanh ◽  
...  
Keyword(s):  
Cross Sections ◽  
Gamma Ray ◽  
Computer Code ◽  
Experimental Results ◽  
Point Energy ◽  
Spectrometric Technique ◽  
End Point ◽  
Theoretical Predictions ◽  
Neutron Reactions ◽  
First Time

Abstract. Seven photo-neutron reactions 197Au(γ,xn)197-xAu (with x=1-7) produced by the bremsstrahlung end-point energy of 60 MeV were identified. In this work, we focus on the measurement of integrated sections. Experiments were carried out based on the activation method in combination with off-line gamma-ray spectrometric technique. The integrated cross sections of the investigated reactions were determined relative to that of the monitoring reaction 197Au(γ,n)196Au. To validate the experimental results, theoretical predictions were also made using the computer code TALYS 1.9. The current integrated cross-sections of the 197Au(γ,xn)197-xAu reactions with 60 MeV bremsstrahlung end point energy are measured for the first time.

One-step synthesis of well-dispersed polypyrrole copolymers under gamma-ray irradiation

2021 ◽  
Vol 12 (5) ◽  
pp. 645-649
Author(s):  
Yu Gu ◽  
Yuqing Qiao ◽  
Yusen Meng ◽  
Ming Yu ◽  
Bowu Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Gamma Ray Irradiation ◽  
One Step ◽  
First Time

Herein, we report for the first time the synthesis of polypyrrole copolymers with good solvent-dispersibility under gamma-ray irradiation at room temperature in air.

scholarly journals SDSS J211852.96−073227.5: The first non-local, interacting, late-type intermediate Seyfert galaxy with relativistic jets

2020 ◽  
Vol 636 ◽  
pp. L12 ◽  
Author(s):  
E. Järvelä ◽  
M. Berton ◽  
S. Ciroi ◽  
E. Congiu ◽  
A. Lähteenmäki ◽  
...  
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Late Type ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Galaxy Interactions ◽  
Non Local ◽  
First Time

It has been often suggested that a tangible relation exists between relativistic jets in active galactic nuclei (AGN) and the morphology of their host galaxies. In particular, relativistic jets may commonly be related to merging events. Here we present for the first time a detailed spectroscopic and morphological analysis of a Seyfert galaxy, SDSS J211852.96−073227.5, at z = 0.26. This source has previously been classified as a gamma-ray emitting narrow-line Seyfert 1 galaxy. We re-observed it with the 6.5 m Clay Telescope and these new, high-quality spectroscopic data have revealed that it is actually an intermediate-type Seyfert galaxy. Furthermore, the results of modelling the Ks-band near-infrared images obtained with the 6.5 m Baade Telescope indicate that the AGN is hosted by a late-type galaxy in an interacting system, strengthening the suggested connection between galaxy interactions and relativistic jets.

scholarly journals Precision measurements on oxygen formation in stellar helium burning with gamma-ray beams and a Time Projection Chamber

2021 ◽  
Author(s):  
Robin Smith ◽  
Moshe Gai ◽  
Sarah Stern ◽  
Deran Schweitzer ◽  
Mohammad Ahmed
Keyword(s):  
Time Projection Chamber ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Angular Distributions ◽  
Helium Burning ◽  
Low Energies ◽  
Important Input ◽  
Novel Method ◽  
Time Projection ◽  
First Time

Abstract Stellar Evolution theory relies on our knowledge of nuclear reactions, with the carbon/oxygen (C/O) ratio, at the end of helium burning, being the single most important input. However, the C/O ratio is still not known with sufficient accuracy, due to large uncertainties in the cross section for the fusion of helium with 12C to form 16O, denoted as the 12C(α,γ)16O reaction. We present initial results at moderately low energies using a novel method, which is significantly different from the experimental efforts of the past four decades. Precise angular distributions of the 12C(α,γ)16O reaction were obtained by measuring the inverse 16O(γ,α)12C reaction with gamma-beams and a Time Projection Chamber detector. These allowed us to measure, for the first time, the interference angle of the l = 1 and 2 partial waves contributing to this reaction (φ12), which agrees with predictions based on the unitarity of the scattering matrix.

scholarly journals Candidate name order effects in New Hampshire: Evidence from primaries and from general elections with party column ballots

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248049
Author(s):  
Bo MacInnis ◽  
Joanne M. Miller ◽  
Jon A. Krosnick ◽  
Clifton Below ◽  
Miriam Lindner
Keyword(s):  
New Hampshire ◽  
Political Engagement ◽  
Order Effects ◽  
Donald Trump ◽  
Major Party ◽  
Percentage Points ◽  
Theoretical Predictions ◽  
General Elections ◽  
Primacy Effects ◽  
First Time

Research in a few U.S. states has shown that candidates listed first on ballots gain extra votes as a result. This study explored name order effects for the first time in New Hampshire, where such effects might be weak or entirely absent because of high political engagement and the use of party column ballots. In general elections (in 2012 and 2016) for federal offices and the governorship and in primaries (in 2000, 2002, and 2004), evidence of primacy effects appeared in 86% of the 84 tests, including the 2016 presidential race, when Donald Trump gained 1.7 percentage points from first listing, and Hillary Clinton gained 1.5 percentage points. Consistent with theoretical predictions, primacy effects were larger in primaries and for major-party candidates in general elections than for non-major-party candidates in general elections, more pronounced in less publicized contests, and stronger in contests without an incumbent running. All of this constitutes evidence of the reliability and generalizability of evidence on candidate name order effects and their moderators.

scholarly journals Detection of the Geminga pulsar with MAGIC hints at a power-law tail emission beyond 15 GeV

2020 ◽  
Vol 643 ◽  
pp. L14
Author(s):  
◽  
V. A. Acciari ◽  
S. Ansoldi ◽  
L. A. Antonelli ◽  
A. Arbet Engels ◽  
...  
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Gamma Ray ◽  
Low Energy ◽  
Significance Level ◽  
Inverse Compton Scattering ◽  
Curvature Radiation ◽  
Sensitivity Range ◽  
Inverse Compton ◽  
First Time

We report the detection of pulsed gamma-ray emission from the Geminga pulsar (PSR J0633+1746) between 15 GeV and 75 GeV. This is the first time a middle-aged pulsar has been detected up to these energies. Observations were carried out with the MAGIC telescopes between 2017 and 2019 using the low-energy threshold Sum-Trigger-II system. After quality selection cuts, ∼80 h of observational data were used for this analysis. To compare with the emission at lower energies below the sensitivity range of MAGIC, 11 years of Fermi-LAT data above 100 MeV were also analysed. From the two pulses per rotation seen by Fermi-LAT, only the second one, P2, is detected in the MAGIC energy range, with a significance of 6.3σ. The spectrum measured by MAGIC is well-represented by a simple power law of spectral index Γ = 5.62 ± 0.54, which smoothly extends the Fermi-LAT spectrum. A joint fit to MAGIC and Fermi-LAT data rules out the existence of a sub-exponential cut-off in the combined energy range at the 3.6σ significance level. The power-law tail emission detected by MAGIC is interpreted as the transition from curvature radiation to Inverse Compton Scattering of particles accelerated in the northern outer gap.

scholarly journals A comparison between short GRB afterglows and kilonova AT2017gfo: shedding light on kilonovae properties

2020 ◽  
Vol 493 (3) ◽  
pp. 3379-3397 ◽  
Author(s):  
A Rossi ◽  
G Stratta ◽  
E Maiorano ◽  
D Spighi ◽  
N Masetti ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Light Curves ◽  
Optical Counterpart ◽  
Wave Source ◽  
Gamma Ray Burst ◽  
Nir Light ◽  
First Time ◽  
Short Grbs

ABSTRACT Multimessenger astronomy received a great boost following the discovery of kilonova (KN) AT2017gfo, the optical counterpart of the gravitational wave source GW170817 associated with the short gamma-ray burst GRB 170817A. AT2017gfo was the first KN that could be extensively monitored in time using both photometry and spectroscopy. Previously, only few candidates have been observed against the glare of short GRB afterglows. In this work, we aim to search the fingerprints of AT2017gfo-like KN emissions in the optical/NIR light curves of 39 short GRBs with known redshift. For the first time, our results allow us to study separately the range of luminosity of the blue and red components of AT2017gfo-like kilonovae in short GRBs. In particular, the red component is similar in luminosity to AT2017gfo, while the blue KN can be more than 10 times brighter. Finally, we exclude a KN as luminous as AT2017gfo in GRBs 050509B and 061201.

scholarly journals Neutron-capture elements in dwarf galaxies

2020 ◽  
Vol 634 ◽  
pp. A84 ◽  
Author(s):  
Á. Skúladóttir ◽  
C. J. Hansen ◽  
A. Choplin ◽  
S. Salvadori ◽  
M. Hampel ◽  
...  
Keyword(s):  
Massive Star ◽  
Milky Way ◽  
Dwarf Galaxies ◽  
Asymptotic Giant Branch ◽  
Agb Stars ◽  
Chemical Enrichment ◽  
Theoretical Predictions ◽  
Low Metallicity ◽  
First Time ◽  
Best Fit

The slow (s) and intermediate (i) neutron (n) capture processes occur both in asymptotic giant branch (AGB) stars, and in massive stars. To study the build-up of the s- and i-products at low metallicity, we investigate the abundances of Y, Ba, La, Nd, and Eu in 98 stars, at −2.4 <  [Fe/H] <  −0.9, in the Sculptor dwarf spheroidal galaxy. The chemical enrichment from AGB stars becomes apparent at [Fe/H] ≈ −2 in Sculptor, and causes [Y/Ba], [La/Ba], [Nd/Ba] and [Eu/Ba] to decrease with metallicity, reaching subsolar values at the highest [Fe/H] ≈ −1. To investigate individual nucleosynthetic sites, we compared three n-rich Sculptor stars with theoretical yields. One carbon-enhanced metal-poor (CEMP-no) star with high [Sr, Y, Zr] >  +0.7 is best fit with a model of a rapidly-rotating massive star, the second (likely CH star) with the i-process, while the third has no satisfactory fit. For a more general understanding of the build-up of the heavy elements, we calculate for the first time the cumulative contribution of the s- and i-processes to the chemical enrichment in Sculptor, and compare with theoretical predictions. By correcting for the r-process, we derive [Y/Ba]s/i = −0.85 ± 0.16, [La/Ba]s/i = −0.49 ± 0.17, and [Nd/Ba]s/i = −0.48 ± 0.12, in the overall s- and/or i-process in Sculptor. These abundance ratios are within the range of those of CEMP stars in the Milky Way, which have either s- or i-process signatures. The low [Y/Ba]s/i and [La/Ba]s/i that we measure in Sculptor are inconsistent with them arising from the s-process only, but are more compatible with models of the i-process. Thus we conclude that both the s- and i-processes were important for the build-up of n-capture elements in the Sculptor dwarf spheroidal galaxy.

Intermediation in Private Equity: The Role of Placement Agents

2019 ◽  
Vol 55 (4) ◽  
pp. 1095-1116
Author(s):  
Matthew D. Cain ◽  
Stephen B. McKeon ◽  
Steven Davidoff Solomon
Keyword(s):  
Real Estate ◽  
Information Asymmetry ◽  
Private Equity ◽  
Abnormal Returns ◽  
Theoretical Predictions ◽  
Illiquid Investments ◽  
First Time ◽  
High Information

Intermediation in private equity involves illiquid investments, professional investors, and high information asymmetry. We use this unique setting to empirically evaluate theoretical predictions regarding intermediation. Using placement agents has become nearly ubiquitous, but agents are associated with significantly lower abnormal returns in venture and real estate funds, consistent with investor capture and influence peddling. However, returns are higher for buyout funds employing a top-tier agent and for first-time real estate and venture funds employing an agent, and are less volatile for agent-affiliated funds, consistent with a certification role. Our results suggest heterogeneous motives for intermediation in the private equity industry.

scholarly journals Time Profile of the Neutrino Burst from the Supernova 1987A

1988 ◽  
Vol 108 ◽  
pp. 426-427
Author(s):  
Hideyuki Suzuki ◽  
Katsuhiko Sato
Keyword(s):  
Monte Carlo ◽  
Neutrino Flux ◽  
Supernova Explosion ◽  
Time Profile ◽  
The Other ◽  
Late Time ◽  
The Core ◽  
Supernova 1987A ◽  
Theoretical Predictions ◽  
First Time

SN1987A gave us the first opportunity to study the supernova core directly by providing us the neutrino signal from the core. The observational data of the neutrino flux detected by Kamiokande[1] and IMB[2] show surprisingly good agreements with the theoretical predictions as a whole[3,4]. The fundamental concept of the collapse driven supernova explosion is confirmed for the first time. On the other hand, there are some puzzles. The most peculiar feature of the data is the 7 seconds gap of the Kamiokande data. The first 8 events of Kamiokande were detected in 2 seconds, following the 7 seconds gap and the last 3 events in 4 seconds. Of course just only 7 seconds gap is not unnatural if small neutrino flux come. But there were detected 3 events after the gap. These 3 events may not be produced by the weak flux. We can estimate the time integrated luminosity of corresponding to the last 3 events and get the large value such as 7 · 1052erg [5]. Can we get out of this inconsistency, 3 events after the 7 seconds gap? If not, we may need to consider some nonstandard mechanism of the neutrino emission at the late time. In order to investigate the probability of the case in which there is a 7 seconds gap before 3 events, we have performed Monte Carlo simulations for the simple model of neutrino flux.

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