Application of a new method to the analysis of radioactive decays

Awaya, Takashi

doi:10.1016/0029-554x(80)90437-1

Cited by 19 publications

(3 citation statements)

References 1 publication

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“…This method has been shown to yield improved results for fitting nuclear lifetimes. 14 A final value for the lifetime for each state was obtained by a weighted average of the four values for each state. The results of the analysis are summarized in Table I.…”

Section: S(t) = (L/n)fr(u)p(t-u)dumentioning

confidence: 99%

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
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A measurement is reported of the mean lifetime, r, for the weak decay of \ 2 C and j^B hypernuclei. The experiment detected energetic protons from the hypernuclear nonmesonic decay A +/?-•«+/?, in coincidence with hypernuclear production by the strangeness-changing reactions X2 C(K~, 7r~ )i 2 C and n C(K~,ir~)p, l \B.The measured ground-state decay lifetimes T Q 2 C)= (2.11 ± 0.31) xlO" 10 sec and T(VB) = (1.92 ±0.22) x 10" 10 sec are compared with AN weak-interaction calculations.PACS numbers: 21.80. + a, 13.75.Ev, 14.20.Jn, 21.30. + y A lambda hyperon bound to a nucleus will decay with a lifetime typical of weak processes ( -10" 10 sec). This is long compared to the normal strong and electromagnetic (strangeness-conserving) nuclear decay processes so that one generally expects the strangeness-changing decay process to occur for a A in the lowest (IS) nuclear shell-model orbital. This weak interaction is characterized by a total decay rate which equals the sum of four partial rates:

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Section: S(t) = (L/n)fr(u)p(t-u)dumentioning

confidence: 99%

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
View full text Add to dashboard Cite

show abstract

“…The methodology of the counting data analysis, which has been extensively studied in analyses in radionuclide research, has a long history. The problems arising from the low statistics of counting data are addressed by the maximum likelihood estimation (MLE) with Poissonian statistics (Mathews and Walker 1965, Sandor et al 1977, Awaya 1980. The problem of the analysis of photon counting data, described by Poissonian statistics, is also similar to that of radionuclide data.…”

Section: Introductionmentioning

confidence: 99%

Artefacts in the analysis of temporal response functions measured by photon counting

Nishimura¹,

Tamura²

2005

Phys. Med. Biol.

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The least-squares (LS) method in fluorescence decay analyses and in time-domain analyses of the diffuse scattering light for data measured by the time-correlated single photon counting (TCSPC) technique is experimentally evaluated, and the artefact in LS analysis for data with different counting statistics is discussed. In single exponential decay analysis, the error of the decay parameter by the LS method is smaller than 10% of the expected true value when the average number of counts per bin (N/k) is more than 1, and the fitting region covers a period on the order of the decay time. In multi-exponential analysis, the decay parameters are sensitively dependent on the counting statistics. In contrast, the fitting by the maximum likelihood estimation (MLE), assuming Poissonian statistics, greatly reduces such dependence of parameters on the counting statistics. In another application, time-domain diffuse scattering measurements, the LS method is only accurate at N/k > 50 (10% error in the absorption coefficient). In particular, the absorption coefficient is largely dependent on the count. In both examples, the problem of stability in the fitting process by MLE still remains: the convergence of the fitting is critically dependent on the selection of initial guesses of the parameters in contrast to the convergence in the LS method. Thus, a hybrid method using the LS method for the determination of the initial guesses is a practical solution to this problem.

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“…New trace element standards employing a polyacrylamide gel matrix have been prepared in Japan (21). Closely allied to standards is analysis of errors; a new statistical technique competing with least squares also comes from Japan (22). Uncertainties associated with presentation of nuclear decay data are discussed by a long time NBS scientist (23 of low-energy /3, y, and X-ray emissions, 63Ni by liquid scintillation counting (24), 14C and 3H by multielement proportional counting (25), and 3H by a source modulation counting technique (26).…”

Section: Standardsmentioning

confidence: 99%

Nucleonics

LYON¹,

ROSS²

1982

Anal. Chem.

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Application of a new method to the analysis of radioactive decays

Cited by 19 publications

References 1 publication

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
View full text Add to dashboard Cite

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
View full text Add to dashboard Cite

Artefacts in the analysis of temporal response functions measured by photon counting

Nucleonics

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Application of a new method to the analysis of radioactive decays

Cited by 19 publications

References 1 publication

Weak Decay ofCΛ12andBGrace1, Barnes2, Eisenstein3 et al. 1985Phys. Rev. Lett.1052230View full textAdd to dashboardCite

Weak Decay ofCΛ12andBGrace1, Barnes2, Eisenstein3 et al. 1985Phys. Rev. Lett.1052230View full textAdd to dashboardCite

Artefacts in the analysis of temporal response functions measured by photon counting

Nucleonics

Contact Info

Product

Resources

About

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
View full text Add to dashboard Cite

Weak Decay ofCΛ12andB
Grace
¹
,
Barnes
²
,
Eisenstein
³

et al. 1985
Phys. Rev. Lett.
105
2
23
0
View full text Add to dashboard Cite