A very low energy tandem accelerator

Black, T.; Hendrix, B.E.; Crosson, E.R.; Fletcher, K.; Karwowski, H. J.; Ludwig, E. J.

doi:10.1016/0168-9002(93)91160-o

Cited by 21 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The total efficiency of the large NaI(Tl) detector was found to be nearly constant (98.3 ± 1.7%) over the experimental energy range using the Monte Carlo codes GEANT4 and MCNPX. The results were consistent with data obtained using the 19 F(p, αγ ) reaction, taken using a minitandem accelerator [30]. This measurement provided a determination of the absolute detection efficiency for 6.13-MeV photons [31,32].…”

Section: B Detector Calibrationsupporting

confidence: 85%

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

146

View full text Add to dashboard Cite

Models of the r process are sensitive to the production rate of 9 Be because, in explosive environments rich in neutrons, α(αn, γ ) 9 Be is the primary mechanism for bridging the stability gaps at A = 5 and A = 8. The α(αn, γ ) 9 Be reaction represents a two-step process, consisting of α + α → 8 Be followed by 8 Be(n, γ ) 9 Be. We report here on a new absolute cross-section measurement for the 9 Be(γ, n) 8 Be reaction conducted using a highly efficient, 3 He-based neutron detector and nearly monoenergetic photon beams, covering energies from E γ = 1.5 MeV to E γ = 5.2 MeV, produced by the High Intensity γ -ray Source of Triangle Universities Nuclear Laboratory. In the astrophysically important threshold energy region, the present cross sections are 40% larger than those found in most previous measurements and are accurate to ±10% (95% confidence). The revised thermonuclear α(αn, γ ) 9 Be reaction rate could have implications for the r process in explosive environments such as type II supernovae.

show abstract

Section: B Detector Calibrationsupporting

confidence: 85%

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

146

View full text Add to dashboard Cite

show abstract

“…The results were consistent with data obtained using the 19 F(p, αγ) reaction, taken using a mini-tandem accelerator [31]. This measurement provided a determination of the absolute detection efficiency for 6.13 MeV photons [32,33].…”

Section: B Detector Calibrationsupporting

confidence: 85%

Cross Section Measurement of 9Be(γ,n)8Be and Implications for α+α+n -> 9Be in the r-Process

Arnold,

Clegg,

Iliadis

et al. 2011

Preprint

View full text Add to dashboard Cite

Models of the r-process are sensitive to the production rate of 9 Be because, in explosive environments rich in neutrons, α (αn, γ) 9 Be is the primary mechanism for bridging the stability gaps at A = 5 and A = 8. The α (αn, γ) 9 Be reaction represents a two-step process, consisting of α + α → 8 Be followed by 8 Be (n, γ) 9 Be. We report here on a new absolute cross section measurement for the 9 Be (γ, n) 8 Be reaction conducted using a highly-efficient, 3 He-based neutron detector and nearly-monoenergetic photon beams, covering energies from E γ = 1.5 MeV to 5.2 MeV, produced by the High Intensity γ-ray Source of Triangle Universities Nuclear Laboratory.In the astrophysically important threshold energy region, the present cross sections are 40% larger than those found in most previous measurements and are accurate to ±10% (95% confidence).The revised thermonuclear α (αn, γ) 9 Be reaction rate could have implications for the r-process in explosive environments such as Type II supernovae.

show abstract

“…All data were taken using the TUNL Low-Energy Beam Facility (LEBF) and the High-Voltage Target Chamber [14]. The LEBF is composed of the Atomic Beam Polarized Ion Source [15] and Mini-Tandem accelerator [16]. The combined acceleration potentials of the source, Mini-Tandem and HV chamber provide deuteron and proton beam energies up to approximately 680 keV.…”

Section: Methodsmentioning

confidence: 99%

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C

View full text Add to dashboard Cite

Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe Ω b with a precision of about 4%. With Ω b tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of theHe total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% ± 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.

show abstract

A very low energy tandem accelerator

Cited by 21 publications

References 3 publications

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

Cross Section Measurement of 9Be(γ,n)8Be and Implications for α+α+n -> 9Be in the r-Process

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C

Contact Info

Product

Resources

About

A very low energy tandem accelerator

Cited by 21 publications

References 3 publications

Cross-section measurement of9Be(γ,n)8Be and implications forArnold1, Clegg2, Iliadis3 et al. 2012Phys. Rev. C

Cross-section measurement of9Be(γ,n)8Be and implications forArnold1, Clegg2, Iliadis3 et al. 2012Phys. Rev. C

Cross Section Measurement of 9Be(γ,n)8Be and Implications for α+α+n -> 9Be in the r-Process

Precision measurements ofH2(d,p)Leonard1, Karwowski2, Brune3 et al. 2006Phys. Rev. C

Contact Info

Product

Resources

About

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

Cross-section measurement of9Be(γ,n)8Be and implications for
Arnold
¹
,
Clegg
²
,
Iliadis
³

et al. 2012
Phys. Rev. C

Precision measurements ofH2(d,p)
Leonard
¹
,
Karwowski
²
,
Brune
³

et al. 2006
Phys. Rev. C