Measurements are reported for the image noise levels in digital radiographs using 256(2), 256(2)-zoom, 512(2), and 1024(2) storage arrays. The noise was essentially the same with 256(2)-zoom or 512(2) arrays, while it was 25% lower for a 256(2) array, and only 15% larger for a 1024(2) array than for a 512(2) array. Compatibility of these results with different models is evaluated. Also the number of bits/pixel was varied to determine the effect on noise; noise before digitization ranged from 4.3 to 0.13 gray levels. The noise level was found to be increased only if the noise was less than approximately one-half of a gray level.

The high-spin states of $^{117,119,121}\mathrm{I}$ have been investigated by in-beam $\ensuremath{\gamma}$-ray spectroscopy via the $^{A}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{A+3}\mathrm{I}$ reactions to study the collective properties of the odd-mass I isotopes. A similar study of $^{123,\phantom{\rule{0ex}{0ex}}125,\phantom{\rule{0ex}{0ex}}127}\mathrm{I}$ is reported in the preceding paper. Two collective features have been observed: $\ensuremath{\Delta}J=1$ bands built on low-lying ${\frac{9}{2}}^{+}$ proton-hole states and $\ensuremath{\Delta}J=2$ bands built on ${\frac{11}{2}}^{\ensuremath{-}}$, ${\frac{7}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ quasiproton states. The $\ensuremath{\Delta}J=2$ energy spacings for the ${\frac{11}{2}}^{\ensuremath{-}}$ bands decrease significantly relative to those for the ground-state bands of the Te core nuclei as $A$ decreases, but not for the ${\frac{7}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ $\ensuremath{\Delta}J=2$ bands. This unexpected decrease can be explained in a generalized seniority scheme. The systematic properties of the $\ensuremath{\Delta}J=2$ bands for all of the odd-mass I isotopes are summarized. These collective properties are examined in terms of both the microscopic and phenomenological approaches. Pulsed-beam-$\ensuremath{\gamma}$ measurements yielded mean lifetimes of $\ensuremath{\tau}=17.5\ifmmode\pm\else\textpm\fi{}1.0, 41.5\ifmmode\pm\else\textpm\fi{}1.5, 13.5\ifmmode\pm\else\textpm\fi{}0.5$ ns for the ${\frac{9}{2}}^{+}$ proton-hole states in $^{117,\phantom{\rule{0ex}{0ex}}119,\phantom{\rule{0ex}{0ex}}121}\mathrm{I}$, respectively. These values imply hindrances of \ensuremath{\sim} ${10}^{4}$ relative to $M1$ Weisskopf estimates for the transitions to the ${\frac{7}{2}}^{+}$ quasiproton states. A spin rotation measurement yielded a $g$ factor for the ${\frac{9}{2}}^{+}$ isomer in $^{119}\mathrm{I}$ of $g=1.21\ifmmode\pm\else\textpm\fi{}0.08$. Another isomer with a mean life of $\ensuremath{\tau}=13\ifmmode\pm\else\textpm\fi{}2$ \ensuremath{\mu}s was observed at 2377 keV in $^{121}\mathrm{I}$.NUCLEAR REACTIONS $^{114\ensuremath{-}118}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{117\ensuremath{-}121}\mathrm{I}$; measured $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}\ensuremath{-}t$ coincidences, $\ensuremath{\gamma}(E, \ensuremath{\theta}, t)$, spin rotation in $B=13.4$ kG; deduced level schemes in odd-mass $^{117\ensuremath{-}121}\mathrm{I}$, $\ensuremath{\gamma}$ multipolarities, ${J}^{\ensuremath{\pi}}$, ${T}_{\frac{1}{2}}$, $g$ factor. Enriched targets, Ge(Li) detectors.

The high-spin states of $^{123,125,127}\mathrm{I}$ have been investigated via the $^{A}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{A+3}\mathrm{I}$ reactions to study the collective properties of the odd-mass I isotopes. In-beam measurements of $\ensuremath{\gamma}$-ray excitations, $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}$-ray angular distributions, and pulsed beam-$\ensuremath{\gamma}$ timing were performed with Ge detectors to determine level energies, decay schemes, $\ensuremath{\gamma}$-ray multipolarities, ${J}^{\ensuremath{\pi}}$ assignments, and lifetime information. A similar study of the $^{117,119,121}\mathrm{I}$ isotopes is reported in the following paper. Two collective features have been identified in these odd-mass I nuclei. Systematic $\ensuremath{\Delta}J=1$ bands built on low-lying ${\frac{9}{2}}^{+}$ proton-hole (4p-1h) states were observed. The ${\frac{9}{2}}^{+}$ bandheads, that involve the excitation of a $1{g}_{\frac{9}{2}}$ proton across the $Z=50$ shell, drop to very low energies near the middle of the neutron shell. The properties of the ${\frac{9}{2}}^{+}$ proton-hole states for all of the odd-mass I isotopes are presented and related to the systematic information for the proton-hole states in the entire $Z>50$ transition region. Systematic $\ensuremath{\Delta}J=2$ bands built on ${\frac{11}{2}}^{\ensuremath{-}}$ ($1{h}_{\frac{11}{2}}$ quasiproton) states, on ${\frac{7}{2}}^{+}$ ($1{g}_{\frac{7}{2}}$ quasiproton) states, and on ${\frac{5}{2}}^{+}$ ($2{d}_{\frac{5}{2}}$ quasiproton) states were also observed. The $\ensuremath{\Delta}J=2$ band spacings generally follow the spacings of the Te-core ground-state bands with the exception of the ${\frac{11}{2}}^{\ensuremath{-}}$ $\ensuremath{\Delta}J=2$ bands, for which the spacings decrease significantly relative to those for the Te cores as $A$ decreases. These systematic properties are discussed in terms of several theoretical approaches to the onset of collectivity in transitional nuclei. An isomer at 2660 keV in $^{123}\mathrm{I}$ was observed to have a mean lifetime $\ensuremath{\tau}=38\ifmmode\pm\else\textpm\fi{}3$ ns.NUCLEAR REACTIONS $^{120\ensuremath{-}124}\mathrm{Sn}(^{6}\mathrm{Li}, 3n)^{123\ensuremath{-}127}\mathrm{I}$; measured $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}(E, \ensuremath{\theta}, t)$; deduced level schemes in odd-mass $^{123\ensuremath{-}127}\mathrm{I}$, $\ensuremath{\gamma}$ multipolarities, ${J}^{\ensuremath{\pi}}$, ${T}_{\frac{1}{2}}$. Enriched targets, Ge(Li) detectors.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProton activation analysis for the measurement of fluorine in food samplesR. E. Shroy, H. W. Kraner, K. W. Jones, J. S. Jacobson, and L. I. HellerCite this: Anal. Chem. 1982, 54, 3, 407–413Publication Date (Print):March 1, 1982Publication History Published online1 May 2002Published inissue 1 March 1982https://doi.org/10.1021/ac00240a014RIGHTS & PERMISSIONSArticle Views65Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (950 KB) Get e-Alertsclose Get e-Alerts

A proton microprobe with windowless exit port has been used to study zinc distributions in various types of skeletal tissues. The use of an external beam facilitated positioning of the targets for examination of particular points of interest. The proton microprobe is uniquely suited to this work since it combines high sensitivity for zinc determination in thick samples with good spatial resolution. Our measurements on rat and rabbit Achilles tendon showed a significant increase in zinc concentrations as the beam moved from the unmineralized collagen into the mineralized attachment site. Cartilage gave a similar result, with calcified cartilage having a greater zinc level than the articular surface on unmineralized epiphyseal cartilage.

The BNL proton microprobe has been used to study migration of molybdenum through reactor grade graphite for temperatures between 1800 and 3100°C. The proton microprobe, with a resolution between 25 and 150 micrometers, provides a unique tool for investigation of the lower temperature and shorter time heatings along with investigation of the microstructure of the system. With a high sensitivity, on the order of 1 ppm, particular attention was paid to the region governed by pore and grain boundary diffusion. The results obtained with the proton microprobe are compared with results obtained using wet chemical techniques.

H451 graphite was sublimed and impurity migration and sublimation behavior examined with a proton microprobe analyzer. Impurities migrate down thermal gradients during heating and are released at free surfaces. They are deposited on cooler surfaces and may form compounds. Sublimed graphite also deposits in cooler regions forming a hard graphitic mass.

The migration of fission products and other impurities through the graphite core of a High Temperature Gas Cooled Reactor is of prime importance in studies of reactor safety. Work in this area is being carried out in which graphite specimens are heated to temperatures up to ~ 3800°C to induce migration of trace elements whose local concentrations are then measured with a proton microprobe. This in...

Properties of high-spin states in $^{113,115,117,119}\mathrm{Sb}$ have been studied via the $^{A}\mathrm{Cd}(^{6}\mathrm{Li},3n)^{A+3}\mathrm{Sb}$ reactions. Using Ge(Li) and Si(Li) detectors, in-beam measurements of $\ensuremath{\gamma}$-ray excitation functions, $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}$-ray angular distributions, and pulsed beam-$\ensuremath{\gamma}$ timing spectra were made to determine level energies, decay schemes, $\ensuremath{\gamma}$-ray multipolarities, ${J}^{\ensuremath{\pi}}$ assignments, isomeric lifetimes, and a $g$ factor. Systematic $\ensuremath{\Delta}J=1$ bands built on low-lying $\frac{9}{{2}^{+}}$ proton-hole (2p-1h) states were observed in these nuclei. The bandheads that involve the excitation of a $1{g}_{\frac{9}{2}}$ proton across the $Z=50$ shell achieve an energy minimum near the middle of the neutron shell. The observed properties of these bands are consistent with significant prolate deformations; the band spacings imply a deformation asymmetry of $\ensuremath{\gamma}=20$ in a triaxial rotor model. In addition, single-particle and single-particle plus core-excitation states were observed in these Sb nuclei. Two isomers were identified, a $\frac{19}{{2}^{(\ensuremath{-})}}$ state at 2796 keV in $^{115}\mathrm{Sb}$ ($\ensuremath{\tau}=230\ifmmode\pm\else\textpm\fi{}4$ ns and $g=+0.290\ifmmode\pm\else\textpm\fi{}0.005$) and a ($\frac{27}{{2}^{+}}$) state in $^{119}\mathrm{Sb}$ ($\ensuremath{\tau}=1.23\ifmmode\pm\else\textpm\fi{}0.13$ s).NUCLEAR REACTIONS $^{110\ensuremath{-}116}\mathrm{Cd}$ ($^{6}\mathrm{Li}$,$3n$)$^{113\ensuremath{-}119}\mathrm{Sb}$; measured $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidences, $\ensuremath{\gamma}(E,\ensuremath{\theta},t)$, spin rotation in $B=10.3$ kG; deduced level schemes in odd-mass $^{113\ensuremath{-}119}\mathrm{Sb}$, $\ensuremath{\gamma}$ multipolarities, ${J}^{\ensuremath{\pi}}$, ${T}_{\frac{1}{2}}$, $g$-factor. Enriched targets, Ge(Li) detectors.

Determination of fluorine in organic samples by chemical techniques is difficult and prone to error. Therefore, a physical method has been developed and is described here. This method is based on the 19F(p, p′γ)19F reaction. Proton beams with energies from 2.8 to 3.5 MeV bombarded the thick samples, producing characteristic 110 keV and 197 keV fluorine gamma rays, which were detected with a Ge(Li) gamma ray detector. This technique has been applied to several vegetation and food samples; results are compared with results from chemical measurements. Calibration has been carried out by measurement of comparative standards at relatively high fluorine levels, measurement of Teflon and by calculation of gamma ray yields from thick biological targets. Sensitivities, backgrounds, and uncertainties of the (p, p′γ) method are evaluated. It is concluded that the 19F(p, p′γ)19F reaction provides a useful independent analytical method.

Construction and use of a windowless-exit port with a proton microprobe apparatus is described. The use of a differential-pumping system permits bombardment of samples at atmospheric pressure without the problems caused by passing the beam through thin foils. Methods used for fabrication of beam collimators and for measurement of the beam diameter are discussed. The sensitivity for trace element determination by observation of K X-rays is given. Sample spectra obtained are presented and contrasted with results obtained with a scanning electron microscope with energy-dispersive X-ray detection. The localization of Zn in a rat incisor is given to demonstrate the type of data uniquely obtainable with the proton microprobe.