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Abstract  

The reduction of99mTc by SnCl2 in the presence of 1,7-bis (2-pyridyl)-2,6-diazaheptane (DPTN) has been investigated in borate buffer solutions with pHs ranging from 6.7 to 9.5. The resulting cationic, neutral and anionic complexes, in addition to TcO2 and TcO 4 impurities, were separated by high voltage paper electrophoresis. The cationic complex turned into neutral and then into an anionic form via hydrolysis. These three species were also separated by gel filtration on a Bio-Gel P-2 column; their formation yields, stability, and the rate of their hydrolysis are presented as a function of the pH, and the results are discussed.

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Abstract  

A novel procedure for measuring the concentration of trace beryllium in different samples has been studied using11B heavy ion activation analysis. The specific reaction,9Be/11B, 2n/18F, is sensitive and selective when using a 10 MeV11Be3+ bombardment energy. The detection limit for a nondestructive analysis is 0.1 ng for a 2 h irradiation in a A cm–2 beam current. A precision of 12% was achieved at the 50 g g–1 level. Beryllium has been determined in a standard beryllium-copper alloy NBS-SRM C1123. Glass samples containing up to 61 trace elements were also analyzed nondestructively. When using a clean vacuum irradiation chamber, the technique might allow ultra-trace determinations, dealing with solid samples of a few milligrams.

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Studies in heavy ion activation analysis

XI. Trace determination possibilities with15N ion bombardment

Journal of Radioanalytical and Nuclear Chemistry
Authors: C. Friedli, M. Colin, and P. Lerch

Abstract  

15N induced radioactivation was used to study the possible trace determination of light elements with 1Z17. 55 nuclear reactions were investigated with ion beam energies ranging from E1ab=10 MeV to E1ab=30 MeV. Three elements were found to be determinable non-destructively, selectively and sensitively: Li, Be and Mg. Nuclear interferences have also been defined and quantified. The technique has been tested by analyzing NBS standards. Finally, Li and Be have been determined in glass samples and Mg in various types of alumina.

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Studies in heavy ion activation analysis

VI. Trace determination possibilities with7Li ion bombardment

Journal of Radioanalytical and Nuclear Chemistry
Authors: C. Friedli, E. Schweikert, and P. Lerch

Abstract  

7Li induced radioactivation was used for the trace determination of hydrogen via the1H(7Li, n)7 Be reaction. At 21 MeV7Li, only boron and magnesium present small nuclear interferences. An activation curve has been established by bombarding a stack of thin mylar foils. The comparison of this curve with the excitation function for the forward reaction, namely7Li(p, n)7 Be, shows that the recoil range from the superficial hydrogen atoms is only 1.7 mg·cm–2, allowing post-irradiation etching. Hydrogen has been determined in titanium and lead bronze at the 100 ppm level with a relative precision of 6 to 10%. Studies of 32 potential interfering elements suggest the extension of Li activation to the trace determination of Na[23Na(7Li,6Li)24Na] and K[39K(7Li, d)44m,44Sc].

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Studies in heavy ion activation analysis

VII. Trace determination possibilities with10B ion bombardment

Journal of Radioanalytical and Nuclear Chemistry
Authors: C. Friedli, E. Schweikert, and P. Lerch

Abstract  

10B induced radioactivation was used for the trace determination of hydrogen via the1H(10B )7Be reaction. At 27 MeV10B++, only boron and magnesium present small nuclear interferences. An activation curve has been established by bombarding stacks of thin mylar foils. The comparison of this curve with the excitation function for the forward reaction, namely10B(p, )7Be, shows that the recoil range from superficial hydrogen atoms is small. Hydrogen has been determined in titanium and lead bronze at the 100 ppm level. Studies of 21 potential interfering elements suggest that10B activation might be suitable for the trace determination of lithium [6Li(10b,n)15O and7Li(10B, 2n)15O] and oxygen [18O(10B,)24Na].

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Abstract  

9Be induced radioactivation was used to study the trace determination of 19 elements at 3 different ion beam energies (Elab=14, 32 and 63 MeV9Be2+). Nine nuclear reactions, yielding radionuclides with half-lives longer than 2.5 m, present potential analytical features. Beside the very sensitive detection of B and N, the multielemental determination of Na, Si, Ca, Sc, and Zn is possible with a9Be ion beam of appropriate incident energy. Nuclear interferences have also been investigated and quantified.

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Studies in heavy ion activation analysis

VIII. Hydrogen trace determination

Journal of Radioanalytical and Nuclear Chemistry
Authors: C. Friedli, E. Schweikert, and P. Lerch

Abstract  

Both7Li and10B induced radioactivation were applied to trace determination of hydrogen via the1H(7Li,n)7Be and1H(10B, )7Be reactions. In both cases, boron and magnesium present nuclear interferences, but their extent does not exceed 0.5%. At the bombarding energies used, 21 MeV7Li++ and 27 MeV10B++ the detection limits are respectively 2 and 0.5 ppm for an iron matrix irradiated for two hours. Due to the recoil of7Be, the samples were carefully prepared to avoid superficial hydrogen contamination. A series of samples which hydrogen content ranges from 15 to 120 ppm was examined, and the results obtained with the two beams were compared.

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Abstract  

A novel procedure for measuring the concentrations of lithium and beryllium in different inorganic and biological samples has been studied using18O heavy-ion activation analysis. The specific reactions,7Li(18O,n)2cF and9Be(180,2)19O, are sensitive and selective if the bombardment energy is 25-MeV18O4+. The detection limits for non-destructive analyses are 10 ng Li and 2 ng Be for a 100-second cyclic irradiation. The technique has been tested by analyzing NBS reference materials. It can be applied to a large range of solid samples.

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Abstract  

The Si(11B, x)34mCl and Si(19F, x)44mSc reactions have been studied in order to work out their capabilities in determining traces of silicon. The first one has been tested with beam energies ranging from 19 to 27 MeV11B; only Mg and Al have shown nuclear interferences and a 30-min 27 MeV11B irradiation yields a 14 ng detection limit. The second reaction, investigated in between 35 and 46 MeV19F, yields a 16 ng detection limit with a 2 hrs 46 MeV19F irradiation; at that energy only Al and P present nuclear interferences.

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Abstract  

The photochemical aquation of K2 TcBr6 in 2M HRr, 1M HClO4 and 1M H2SO4 has been studied. The absorption spectra of the various Tc(IV) species were measured after the electrophoretic separation. The spectrophotometric changes and the yield of each species as a function of the UV irradiation time were determined. After 25 hours of irradiation of HBr and HClO4 solutions the main species were the cationic ones (80%) but in H2SO4 solution the neutral species reached a yield of 90%. The oxidation of Tc(IV) species to TcO 4 proceeded more rapidly and extensively in HClO4 than in HBr and H2SO4.

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