共查询到20条相似文献,搜索用时 31 毫秒
1.
In order to apply the stable-isotope dilution method to charged-particle activation analysis, determination of strontium in biological materials has been studied by proton activation using isotopically enriched86Sr as a spike. To avoid thermal decomposition of biological materials due to the low penetrating power of proton beam, and to eliminate interfering nuclear reactions due to the matrix elements, strontium in the sample and/or isotopic mixture as a comparator was separated chemically together with most of calcium before bombardment, and the fraction isolated was converted to a silica-gel pellet as a most suitable physical and chemical form for bombardment. By processing as above, it was demonstrated that the strontium contents in the biological materials can be determined accurately, precisely and easily. Through a series of experiments, the method was also proved to be applicable for charged-particle activation analysis. 相似文献
2.
J. P. Thomas J. Engerran J. Tousset 《Journal of Radioanalytical and Nuclear Chemistry》1975,25(1):163-177
Ion-beam surface analysis of light elements such as oxygen and carbon in light matrices (boron in our case) is mainly subject
to matrix interferences. Using a telescope detection system we show that (d, p) reaction for carbon and proton backscattering
for oxygen are able to lead to concentration profiles on the first microns of bulk boron samples. Data processing is described
and analytical results are shown, making evidence of the purification obtained using electronic bombardment furnace. Comparing
with other phhsical methods of analysis, limitation and improvements of this procedure are discussed.
相似文献
3.
K. Masumoto M. Hara D. Hasegawa E. Iino M. Yagi 《Journal of Radioanalytical and Nuclear Chemistry》1997,217(2):247-253
The internal standard method coupled with the standard addition method has been applied to photon activation analysis and proton activation analysis of minor elements and trace impurities in various types of iron and steel samples issued by the Iron and Steel Institute of Japan (ISIJ). Samples and standard addition samples were once dissolved to mix homogeneously, an internal standard and elements to be determined and solidified as a silica-gel to make a similar matrix composition and geometry. Cerium and yttrium were used as an internal standard in photon and proton activation, respectively. In photon activation, 20 MeV electron beam was used for bremsstrahlung irradiation to reduce matrix activity and nuclear interference reactions, and the results were compared with those of 30 MeV irradiation. In proton activation, iron was removed by the MIBK extraction method after dissolving samples to reduce the radioactivity of56Co from iron via56Fe(p,n)56Co reaction. The results of proton and photon activation analysis were in good agreement with the standard values of ISIJ. 相似文献
4.
G. Demortier 《Journal of Radioanalytical and Nuclear Chemistry》1978,45(2):459-496
Gamma-ray yields from bombardment with protons of thick targets of Ti, V, Mn, Cr, Fe, Co, Ni, Cu and Zn are tabulated for
proton energies ranging between 0.6 and 3.2 MeV. The applications of these reactions for quantitative analysis of these chemical
elements are discussed. The sensitivity of this technique of analysis is poorer than the PIXE method for these transition
elements, but is sufficient for rapid and accurate quantitative analysis of alloys when elements are present in concentrations
down to 1%. The knowledge of the γ-ray energies and intensities produced by the bombardment of these elements with protons
is also necessary for solving interferences with several γ-rays induced in light elements, for which the proton induced γ-ray
technique is sensitive, without any correction for photon attenuation. 相似文献
5.
A rapid method for the determination of Al, V and Ti has been developed and is used for the analysis of these elements in different ores and alloys. An isotopic neutron source252Cf having a thermal neutron flux of the order of 8.5×107 n·cm–2 sec–1 has been used for thermal neutron bombardment. Activity measurements were performed on a HPGe detector coupled to a PC based MCA unit. Depending on the half-life of the (n, ) product, different irradiation and cooling times were employed and thus the elements of interest were analyzed sequentially. 相似文献
6.
An accurate and simple method has been developed for the determination of Pt, Ru, Ir and other elements employing instrumental neutron activation analysis (INAA). Nondestructive analysis has been carried out for the determination of these elements in different rock samples such as Dolerite, Dyke Dolerite, Country Basalt, Hyaloclastite, Trachyte, Ijolite, Spillite, Diorite and Lamprophyre from various locations like Daman, Tapti, Murud, Talasari, Ranala and Bassein in Maharashtra state. High flux provided by the CIRUS reactor (1×1013 n cm–2s–1) has been used for thermal neutron bombardment followed by radioassaying of the (n,) products on a HPGe detector coupled to a PC-based MCA unit. 相似文献
7.
O. Bonnet-Masimbert M. F. Prenat 《Journal of Radioanalytical and Nuclear Chemistry》1972,12(2):151-155
A method was developed for assay of iron based on its radioactivation by means of a 26 MeV proton bombardment. The technique
was sensitive to 20 to 100 ppm of iron diluted by large excesses of extraneous proteins and major or trace mineral elements.
It could be shown that the incorporation of iron in one blastodisc, from the stage of 1 somite to that of 16 somites, is strictly
parallel with the weight increase of its ashes. 相似文献
8.
In order to demonstrate the usefulness of alpha-particle activation analysis, simultaneous determination of P, Cl, K and Ca in commercially available control serums has been studied fundamentally. After thick target yield curves of radionuclides produced from the element to be determined were measured as a function of alpha energy together with those of the interferences, an optimum working standard for the present experiments was provided by applying the internal standard method to a human serum under the most suitable bombardment conditions. Then, the concentrations of the above four elements in several control serums were determined efficiently and reasonably by ordinary alpha-particle activation analysis. 相似文献
9.
D Bongiorno L Ceraulo A Mele W Panzeri A Selva V T Liveri 《Journal of mass spectrometry : JMS》2001,36(11):1189-1194
Ionspray (IS) and fast atom bombardment (FAB) positive ionization mass spectrometry (MS) of 1 : 1 beta-cyclodextrin (beta-CD)-melatonin (MLT) host-guest complex allowed the detection of gaseous protonated 1 : 1 beta-CD-MLT. Tandem MS collision-induced dissociation (CID) of such protonated 1 : 1 beta-CD-MLT species showed the proton (charge) to be retained to a significant extent by the host and by its cage fragmentation products, in spite of the higher proton affinity of MLT with respect to that of beta-CD. This requires an endothermic guest-to-host proton transfer to occur within the gaseous association. Collisional activation could be accounted for by the promotion of such an endothermic process; however, the proton affinity decrease of the guest determined by the loss of the elements of acetamide, which is a dominant MS dissociation reaction of pure protonated MLT, could also provide a rationale for such an endothermic guest-to-host proton transfer. This proposal parallels the reaction scheme we had previously formulated for the analogous MS and tandem MS behaviour of 1 : 1 beta-CD-5-methoxytryptamine inclusion complex with the protonated 5-methoxytryptamine guest undergoing deamination. 相似文献
10.
J. A. Cookson A. T. G. Ferguson F. D. Pilling 《Journal of Radioanalytical and Nuclear Chemistry》1972,12(2):39-52
Well focused beams of protons and other ions provide a very powerful means of determining how the elemental composition of
a sample varies over its surface. Observation of the X-rays from proton bombardment can provide great sensitivity in most
cases, while detection of nuclear effects has special applicability for elements of low atomic weight. A focusing system using
high precision magnetic quadrupoles was designed and built for use with the IBIS 3 MeV Van de Graaff generator. Measurements
of the first order focusing and aberrations agreed satisfactorily with theoretical predictions. The focused beam of 3 MeV
protons was measured to have a diameter of less than 4 μm. The target chamber, deflection system and display system are described
and examples given of use of the system. Backgrounds in X-ray detection are discussed and limits of detection are given. 相似文献
11.
Irradiation effects of 35 MeV proton beam bombardment on polyaniline (PAn) have been studied. PAn was made by standard MacDiarmid method, and the irradiation was performed at ambient temperature lower than 20°C. A 511 keV γ photon was detected by γ spectrum analysis, and a nuclear reaction 14N(p,α)11C in collaboration of 12C(p,pn)11C took place. By means of chemical ionization, mass spectra of samples before and after ion bombardment were recorded. Experimental results showed that products such as
and cyclic compounds like
and
were produced. IR spectra and SEM micrographs gave results of vibrational frequency shifts and morphology consistent with mass spectrometry. Finally we conclude that high energy proton beam bombardment resulted in main-chain scission and carbonization of PAn. Although the electrical conductivity reduced from 0.72 to 0.62 S cm-1, it retained at the same level. This implies that PAn might be used under the influence of high energy radiation. 相似文献
Full-size image (1K)
Full-size image (1K)
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12.
An accurate and simple method has been developed for the determination of Pt, Ru, Ir and other elements employing instrumental neutron activation analysis (INAA). Nondestructive analysis has been carried out for the determination of these elements in different rock samples such as Dolerite, Dyke Dolerite, Country Basalt, Hyaloclastite, Trachyte, Ijolite, Spillite, Diorite and Lamprophyre from various locations like Daman, Tapti, Murud, Talasari, Ranala and Bassein in Maharashtra state. High flux provided by the CIRUS reactor (1×1013 n cm?2s?1) has been used for thermal neutron bombardment followed by radioassaying of the (n,γ) products on a HPGe detector coupled to a PC-based MCA unit. 相似文献
13.
Proton-induced thick-target gamma-ray yields for the elemental analysis of the Z=3–9, 11–21 elements
A. Anttila R. Hänninen J. Räisänen 《Journal of Radioanalytical and Nuclear Chemistry》1981,62(1-2):293-306
A systematic study of the relative thick-target yields of prompt γ-rays following proton bombardment has been carried out at Ep=1, 1.7 and 2.4 MeV for the elements Z=3–9, 11–21. The relevant spectra for each element are depicted and a table of the most suitable γ-rays for elemental analysis are given. Depending on the strength of the reaction cross section, the sensitivity limits of the detection vary from ppm to a few percent under practical measuring arrangements. Particular aspects of the measuring techniques are discussed. 相似文献
14.
M. C. Cantone N. Molho L. Pirola 《Journal of Radioanalytical and Nuclear Chemistry》1985,91(1):197-203
An investigation of the quantitative content of Cd and Ti in human serum samples by proton nuclear activation (PNA) has been performed and the results are presented. The activation has been induced by a 13.5 MeV proton beam of the AVF cyclotron of the University of Milan, via a (p, n) reaction on the nuclei of the target. For the quantitative determination a known amount of a reference element has been added to the samples and comparison has been made with a standard sample containing also known quantities of the elements studied. Response linearity, reproducibility and possible contaminations have been tested. 相似文献
15.
M. A. Rizzutto N. Added M. H. Tabacniks F. Falla-Sotelo J. F. Curado C. Francci R. A. Markarian A. Quinelato F. Youssef M. Mori M. Youssef 《Journal of Radioanalytical and Nuclear Chemistry》2006,269(3):683-687
Summary A collaboration project between the School of Dentistry and the Institute of Physics of the University of S?o Paulo has been
established to measure elemental concentrations in teeth by proton induced X-ray emission (PIXE) and heavy ion elastic recoil
detection analysis (HI-ERDA) techniques. Data on trace elements in human, bovine and swine teeth, analyzed by PIXE with a
2.4 MeV proton beam, were compared and concentrations for several elements were obtained with tens of mg/g sensitivity. HI-ERDA
measurements employing a 52 MeV Cl beam were done to evaluate changes in elementary concentration in dental enamel after bleaching
treatment with different products in 25 bovine incisors teeth. This non-destructive technique allowed the measurements of
Ca, P, O and C concentrations above the limit of 100 mg/g. 相似文献
16.
17.
G. J. Stock J. B. Cross E. A. Schweikert 《Journal of Radioanalytical and Nuclear Chemistry》1979,54(1-2):191-203
Characteristic K, L and M X-ray and background production trends from high energy heavy ion bombardment were investigated
on a series of target elements (14≤Z≤92) using 0.5 MeV/amu and 1 MeV/amu Nn+, On+, Cun+, Krn+ and Xen+ beams. X-ray production for K and L shell X-rays roughly followed the same trends, i.e. increased yield with projectile size
and energy and decreased yield with increasing X-ray energy. Broad simultaneous multielement coverage can be achieved using
K, L and M Lines. Experimental detection limits of 0.8 to 10 ppm were obtained for elements between Mn and Se with K X-ray
detection, between Sm and Pb using L X-ray detection, and for Th and U via M X-ray detection in biological samples with a
1MeV/amu Kr7+ beam of 70 nA for 1000 s. These detection limits are better for many elements than those obtained with a 1.65 MeV proton
beam. 相似文献
18.
The sensitivities for the determination of 19 elements from Z = 44 to Z = 82, by means of 10-MeV proton activation, have been calculated from experimentally measured yields for 51 radioisotopes obtained mainly via (p,n) reactions. For an irradiation of 1 h at a beam current of 1 μA, the sensitivities established experimentally are about 0.02–2 p.p.m. for Ru, Pd, Ag, Cd, Sn, Sb, Te and I, 0.5–100 p.p.m. for In, W, Re, Ir, Pt, Au, Hg, Tl and Pb, and 15–900 p.p m- for Rh and Ba. Experimental results for the non-destructive analysis of these 19 elements in Al, Ag, Au, Co, Dy, Ho, Ir, Nb, Pr, Rh, Si, Ta and Tb, are presented. 相似文献
19.
W. Arshed O. A. Akanle N. M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》1994,179(2):349-355
Proton induced gamma-ray emission (PIGE) and proton induced X-ray emission (PIXE) analysis was employed to investigate the distribution of the concentration of fluorine and ten other elements along sections of teeth samples, extracted from eight individuals. These sections which included the bulk of dentine and enamel were scanned using a proton beam of 250 m diameter. Rutberford backscattering spectra were also collected in order to obtain information about the concentration of major elements and to correct for matrix inhomogeneities. 相似文献
20.
I. F. Shaimukhametova S. R. Allayarov S. A. Bogdanova G. P. Belov K. D. Semavin S. V. Demidov D. A. Dixon 《High Energy Chemistry》2018,52(5):407-413
Energy characteristics of the irradiated surface of a polytetrafluoroethylene film depend on the energy and fluence of bombarding MeV protons. Irradiation with 2–4 MeV protons leads to an increase in the surface free energy; 4 MeV protons at a fluence of 1015 proton/cm2 increase the polarity of the polymer surface by 40 times due to the appearance of functional groups, the polarity enhancement being manifested in an increase in the acid–base component of the surface energy by more than a factor of 50. There is a correlation between the dispersion component of the surface energy and the degree of crystallinity of the near-surface layer of the polymer a period. They both grow symbatically in the case of bombardment with 1–2 MeV protons and decrease upon irradiation with 4 MeV protons. It has been found that dehydrofluorination results in carbonization of the irradiated surface, a decrease in the fluorine content, and an increase in the proportion of oxygen due to oxidation of the radicals generated by proton bombardment. 相似文献