Design and commissioning of a timestamp-based data acquisition system for the DRAGON recoil mass separator

Christian, G.; Akers, C.; Connolly, D.; Fallis, J.; Hutcheon, D. A.; Olchanski, K.; Ruiz, C.

doi:10.1140/epja/i2014-14075-0

Cited by 13 publications

(12 citation statements)

References 30 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The total kinetic energy and stopping power of the recoil ions was measured in a multi-anode ionization chamber (IC) [15]. Coincidences between recoils and prompt γ rays were identified using a timestamp-based algorithm [16]. The 39 Ca recoils were separated from a background of scattered and charge-changed 38 K ("leaky beam") based primarily on the local time of flight (TOF) between the two MCPs ("MCP TOF") and the time difference between the γ ray and the upstream MCP ("separator TOF").…”

Section: Methodsmentioning

confidence: 99%

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

et al. 2018

Self Cite

View full text Add to dashboard Cite

Background: Classical novae are cataclysmic nuclear explosions occurring when a white dwarf in a binary system accretes hydrogen-rich material from its companion star. Novae are partially responsible for the galactic synthesis of a variety of nuclides up to the calcium (A ∼ 40) region of the nuclear chart. Although the structure and dynamics of novae are thought to be relatively well understood, the predicted abundances of elements near the nucleosynthesis endpoint, in particular Ar and Ca, appear to sometimes be in disagreement with astronomical observations of the spectra of nova ejecta. Purpose: One possible source of the discrepancies between model predictions and astronomical observations is nuclear reaction data. Most reaction rates near the nova endpoint are estimated only from statistical model calculations, which carry large uncertainties. For certain key reactions, these rate uncertainties translate into large uncertainties in nucleosynthesis predictions. In particular, the 38 K(p,γ ) 39 Ca reaction has been identified as having a significant influence on Ar, K, and Ca production. In order to constrain the rate of this reaction, we have performed a direct measurement of the strengths of three candidate = 0 resonances within the Gamow window for nova burning, at 386 ± 10 keV, 515 ± 10 keV, and 689 ± 10 keV. Method: The experiment was performed in inverse kinematics using a beam of unstable 38 K impinged on a windowless hydrogen gas target. The 39 Ca recoils and prompt γ rays from 38 K(p,γ ) 39 Ca reactions were detected in coincidence using a recoil mass separator and a bismuth-germanate scintillator array, respectively. Results: For the 689 keV resonance, we observed a clear recoil-γ coincidence signal and extracted resonance strength and energy values of 120 +50 −30 (stat.) +20 −60 (sys.) meV and 679 +2 −1 (stat.)±1(sys.) keV, respectively. We also performed a singles analysis of the recoil data alone, extracting a resonance strength of 120 ± 20(stat.)±15(sys.) meV, consistent with the coincidence result. For the 386 keV and 515 keV resonances, we extract 90% confidence level upper limits of 2.54 meV and 18.4 meV, respectively. Conclusions: We have established a new recommended 38 K(p,γ ) 39 Ca rate based on experimental information, which reduces overall uncertainties near the peak temperatures of nova burning by a factor of ∼250. Using the rate obtained in this work in model calculations of the hottest oxygen-neon novae reduces overall uncertainties on Ar, K, and Ca synthesis to factors of 15 or less in all cases.

show abstract

Section: Methodsmentioning

confidence: 99%

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The 10 B recoils were detected by the DSSSD in coincidence with γ rays in the BGO array. Further discrimination was provided using software cuts on the separator time-of-flight (see Figure 6), which is defined as the time difference between a γ hit in a BGO detector and a hit in the DSSSD at the focal plane of DRAGON [14]. DRAGON is very efficient in rejecting unreacted beam ions for (α, γ) reactions, with demonstrated suppression factors of > 10 13 , which can be increased by few orders of magnitude, by using the aforementioned software cuts [1,5,15].…”

Section: Particle Identificationmentioning

confidence: 99%

Beyond the acceptance limit of DRAGON: The case of the 6Li(α,γ)
Psaltis
¹
,
Chen
²
,
Connolly
³

et al. 2021
Nuclear Instruments and Methods in Physics Research Section A:
Self Cite
3
0
2
0
View full text Add to dashboard Cite

Radiative capture reactions play a pivotal role for our understanding of the origin of the elements in the cosmos. Recoil separators provide an effective way to study these reactions, in inverse kinematics, and take advantage of the use of radioactive ion beams. However, a limiting factor in the study of radiative capture reactions in inverse kinematics is the momentum spread of the product nuclei, which can result in an angular spread larger than the geometric acceptance of the separator. The DRAGON facility at TRIUMF is a versatile recoil separator, designed to study radiative capture reactions relevant to astrophysics in the A∼10-30 region. In this work we present the first attempt to study with DRAGON a reaction, 6 Li(α, γ) 10 B, for which the recoil angular spread exceeds DRAGON's acceptance. Our result is in good agreement with the literature value, showing that DRAGON can measure resonance strengths of astrophysically important reactions even when not all the recoils enter the separator.

show abstract

“…The transmitted ions are then stopped in the DSSD, where their kinetic energy is measured. Coincidences between recoils and prompt γ rays were identified by a timestampbased algorithm [35].…”

Section: Experiments Descriptionmentioning

confidence: 99%

“…These are: the recoil chargestate fraction ( f q ), MCP transmission efficiency (τ MCP ), MCP detection efficiency ( MCP ), and detection efficiency of the DSSD (ε DSSD ). λ tail is the live time fraction of the focal plane DAQ, whereas λ coinc is the live time fraction where both the target (head) and focal plane (tail) DAQs are able to accept new triggers [35].…”

Section: A Thick Target Yield Reaction Cross Section and Resonance Strengthmentioning

confidence: 99%

First inverse kinematics study of the Ne22(p,γ)Na23 reaction and its role in AGB star and classical nova nucleosynthesis

et al. 2020

Self Cite

View full text Add to dashboard Cite

Background: Globular clusters are known to exhibit anomalous abundance trends such as the sodium-oxygen anticorrelation. This trend is thought to arise via pollution of the cluster interstellar medium from a previous generation of stars. Intermediate-mass asymptotic giant branch stars undergoing hot bottom burning (HBB) are a prime candidate for producing sodium-rich oxygen-poor material, and then expelling this material via strong stellar winds. The amount of 23 Na produced in this environment has been shown to be sensitive to uncertainties in the 22 Ne(p, γ ) 23 Na reaction rate. The 22 Ne(p, γ ) 23 Na reaction is also activated in classical nova nucleosynthesis, strongly influencing predicted isotopic abundance ratios in the Na-Al region. Therefore, improved nuclear physics uncertainties for this reaction rate are of critical importance for the identification and classification of pre-solar grains produced by classical novae. Purpose: At temperatures relevant for both HBB in AGB stars and classical nova nucleosynthesis, the 22 Ne(p, γ ) 23 Na reaction rate is dominated by narrow resonances, with additional contribution from direct capture. This study presents new strength values for seven resonances, as well as a study of direct capture. Method: The experiment was performed in inverse kinematics by impinging an intense isotopically pure beam of 22 Ne onto a windowless H 2 gas target. The 23 Na recoils and prompt γ rays were detected in coincidence using a recoil mass separator coupled to a 4π bismuth-germanate scintillator array surrounding the target. Results: For the low-energy resonances, located at center of mass energies of 149, 181, and 248 keV, we recover stength values of ωγ 149 = 0.17 +0.05 −0.04 , ωγ 181 = 2.2 ± 0.4, and ωγ 248 = 8.2 ± 0.7 μeV, respectively. These results are in broad agreement with recent studies performed by the LUNA and TUNL groups. However, for the important reference resonance at 458 keV we obtain a strength value of ωγ 458 = 0.44 ± 0.02 eV, which is significantly lower than recently reported values. This is the first time that this resonance has been studied completely independently from other resonance strengths. For the 632-keV resonance we recover a strength value of ωγ 632 = 0.48 ± 0.02 eV, which is an order of magnitude higher than a recent study. For reference resonances at 610-and 1222-keV, our strength values are in agreement with the literature. In the case of direct capture, we recover an S factor of 60 keV b, consistent with prior forward kinematics experiments. Conclusions: In summary, we have performed the first direct measurement of 22 Ne(p, γ ) 23 Na in inverse kinematics. Our results are in broad agreement with the literature, with the notable exception of the 458-keV

show abstract

Design and commissioning of a timestamp-based data acquisition system for the DRAGON recoil mass separator

Cited by 13 publications

References 30 publications

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

Beyond the acceptance limit of DRAGON: The case of the 6Li(α,γ)
Psaltis
¹
,
Chen
²
,
Connolly
³

et al. 2021
Nuclear Instruments and Methods in Physics Research Section A:
Self Cite
3
0
2
0
View full text Add to dashboard Cite

First inverse kinematics study of the Ne22(p,γ)Na23 reaction and its role in AGB star and classical nova nucleosynthesis

Contact Info

Product

Resources

About

Design and commissioning of a timestamp-based data acquisition system for the DRAGON recoil mass separator

Cited by 13 publications

References 30 publications

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

Direct measurement of astrophysically important resonances in K38(p,γ)Ca39

Beyond the acceptance limit of DRAGON: The case of the 6Li(α,γ)Psaltis1, Chen2, Connolly3 et al. 2021Nuclear Instruments and Methods in Physics Research Section A: Self Cite3020View full textAdd to dashboardCite

First inverse kinematics study of the Ne22(p,γ)Na23 reaction and its role in AGB star and classical nova nucleosynthesis

Contact Info

Product

Resources

About

Beyond the acceptance limit of DRAGON: The case of the 6Li(α,γ)
Psaltis
¹
,
Chen
²
,
Connolly
³

et al. 2021
Nuclear Instruments and Methods in Physics Research Section A:
Self Cite
3
0
2
0
View full text Add to dashboard Cite