Comparison of efficiency functions for Ge gamma-ray detectors in a wide energy range

Kis, Zoltán; Fazekas, B.; Östör, J.; Révay, Zs.; Belgya, T.; Molnár, Gábor; Koltay, László

doi:10.1016/s0168-9002(98)00778-5

Cited by 61 publications

(24 citation statements)

References 12 publications

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“…This is a common problem when using tantalum backings, since fluorine is part of the extraction process of tantalum, making it very hard to obtain tantalum with sufficiently low fluorine contamination levels. Heating of the tantalum backing in a high vacuum chamber did not decrease the 19 • at 8 cm distance from the center of the target (Fig. 3a).…”

Section: Experimental Setup and Proceduresmentioning

confidence: 91%

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Proton capture on17O and its astrophysical implications

et al. 2012

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Background: The reaction17 O(p, γ) 18 F influences hydrogen-burning nucleosynthesis in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars and classical novae. In the relevant temperature range for these environments (T9 = 0.01-0.4), the main contributions to the rate of this reaction are the direct capture process, two low lying narrow resonances (Er = 65.1 and 183 keV) and the low-energy tails of two broad resonances (Er = 557 and 677 keV).Purpose: Previous measurements and calculations give contradictory results for the direct capture contribution which in turn increases the uncertainty of the reaction rate. In addition, very few published cross section data exist for the high energy region that might affect the interpretation of the direct capture and the contributions of the broad resonances in the lower energy range. This work aims to address these issues.Method: The reaction cross section was measured in a wide proton energy range (Ec.m. = 345 -1700 keV) and at several angles (θ lab = 0• , 45The observed primary γ-transitions were used as input in an R-matrix code in order to obtain the contribution of the direct capture and the two broad resonances to the low-energy region.Results: The extrapolated S-factor from the present data is in good agreement with the existing literature data in the low-energy region. A new reaction rate was calculated from the combined results of this work and literature S-factor determinations. Resonance strengths and branchings are reported for several 18 F states. Conclusions:We were able to extrapolate the astrophysical S-factor of the reaction 17 O(p, γ) 18 F at low energies from cross section data taken at higher energies. No significant changes in the nucleosynthesis are expected from the newly calculated reaction rate.

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Section: Experimental Setup and Proceduresmentioning

confidence: 91%

“…Figure 5 shows an example of a full energy peak, a single escape peak and a double escape peak efficiency curve. The peak efficiency curve was fitted with the function [19] …”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Proton capture on17O and its astrophysical implications

et al. 2012

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“…The number of parameters, I , was chosen by Lin et al [8] to be 6, for the energy range 300-9700 keV. Kis et al [9] used up to 9 parameters for the range 50-11000 keV. Such a large number is not needed for a narrower energy range, and may be impractical when the number of measured efficiencies is limited, because the number of parameters must always be fewer than the number of measurements, ideally many fewer.…”

Section: Previous Workmentioning

confidence: 99%

“…Functions which do not sufficiently constrain the values in between the fitted points are useless for this purpose. The criterion stated in [9] for determining the number of needed parameters is as follows: "In order to justify the introduction of the (n+1)th parameter in the fitting the difference between the chi-squares for n parameters and n+1 parameters has to be greater than 3.841, which comes from the tabulated values of the chi-square distribution with one parameter." The functions of the class (4) were built into the code Hypermet-PC [10], and are also now commonly used in commercially available software sold with gamma spectrometry systems.…”

Section: Previous Workmentioning

confidence: 99%

“…This represents the situation when counting statistic are negligible., Very strong correlations are present between activities measured for different activation detectors for all gamma lines from 658 keV and up. The correlations between the two pairs of gamma lines for Y-88 and Co-60 cause highly correlated results above 900 keV Figure 3 shows the standard deviations and correlation matrix for efficiencies calculated using equation (9) when the statistical counting errors from the calibration, shown in row 5 of Table 1, are included together with the source strength uncertainties. The counting errors dilute the correlation between the pairs of gamma lines for Y-88 and Co-60, and have a remarkable effect on the correlations for the high energy part of the matrix (compare with Fig.…”

Section: -P4mentioning

confidence: 99%

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Covariances for Gamma Spectrometer Efficiency Calibrations

Williams

2016

EPJ Web of Conferences

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Abstract. An essential part of the efficiency calibration of gamma spectrometers is the determination of uncertainties on the results. Although this is routinely done, it often does not include the correlations between efficiencies at different energies. These can be important in the subsequent use of the detectors to obtain activities for a set of dosimetry reactions. If those values are not mutually independent, then obviously that fact could impact the validity of adjustments or of other conclusions resulting from the analysis. Examples are given of detector calibrations in which the correlations are calculated and propagated through an analysis of measured activities.

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In‐Beam Prompt γ‐Activation Analysis

Révay

2009

Encyclopedia of Analytical Chemistry

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Prompt γ‐activation analysis (PGAA) is a rapidly developing nuclear analytical technique for the determination of elemental and isotopic composition. The largest neutron research centers and many smaller research reactors operate in‐beam PGAA instruments for the purpose of a wide variety of analyses. PGAA is a nondestructive analytical technique and is suitable for the analysis of light elements, especially hydrogen and boron, as well as some trace elements (e.g. rare earths and cadmium). Because of the deep penetration of both neutrons and γ‐rays, PGAA is suitable for the analysis of samples in closed containers. As the technique is nondestructive and does not require any sample preparation, it is especially useful for the investigation of precious objects (e.g. archaeological artifacts) or hazardous materials. The basic principles of the method, the instrumentation, and some basic issues of the installation, and operation of the in‐beam PGAA technique are all described in this article. A few typical applications are also introduced.

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Comparison of efficiency functions for Ge gamma-ray detectors in a wide energy range

Cited by 61 publications

References 12 publications

Proton capture on17O and its astrophysical implications

Proton capture on17O and its astrophysical implications

Covariances for Gamma Spectrometer Efficiency Calibrations

In‐Beam Prompt γ‐Activation Analysis

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