Tantalum Target

To avoid interferences of isobaric atomic ions of different elements and polyatomic ions at the same nominal mass, off line separation of matrix elements or analyte separation can be applied and/or enrichment and hyphenated techniques such as HPLC- or CE-ICP-MS. Analytical procedures have been developed in the author s laboratory for the determination of spallation nuclides in an irradiated tantalum target using HPLC and CE coupled on line to ICP-MS after dissolution and separation of the tantalum matrix.12,17 The mass spectra of rare earth elements (REEs)... 

Figure 6.6 Mass spectrum of rare earth elements tREEs) measured by CE-ICP-MS with on line separation of analytes (50 nl solution volume) a) natural isotopic pattern, concentration of each REE - 800ngg b) in an irradiated tantalum target (). S. Becker and H. ]. Dietze, Int. /. Mass Spectrom. Ion Proc. 197, 1-35 (2000). Reproduced by permission of the Royal Society of Chemistry.)...

Table 9.40 Concentration of different spallation nuclides of the lanthanides ((j-g g 1) in an irradiated tantalum target.

Table 9.41 Nuclide abundances of gadolinium (%) produced via spallation reactions in an irradiated tantalum target via spallation reactions.

The experiment on the observation of 7r+7r- atoms was carried out at the 70 GeV proton synchrotron (U-70) at Serpukhov [31,32]. Pionic atoms and 7r+7r pairs ( free pairs) were produced in a 8pm thick tantalum target ( thick target) inserted into the internal proton beam. The atoms can either annihilate into 7r°7r° pairs or break up (ionize) into 7r+7r pairs ( atomic pairs) inside the same target. The free and atomic pairs get into the 40 m long vacuum channel (the acceptance is 3.8 10-5 sr) at 8.4° to the proton beam and are detected by the setup in the 0.8 4- 2.4GeV/c pion momentum interval. 

FIG. 2. Bremsstrahlung photon intensity vs emission angle from a tantalum target with incident electron energies of 5.0 Me V, 7.5 Me V and 10 Me V. 

Becker,. S., Kerl,W., and Dietze, H.-J. (1999). Nuclide analysis of an irradiated tantalum target of a spallation neutron source using high performance ion chromatography and inductively coupled plasma mass spectrometry. Ana/. Chim.Acta 387(2), 145. 

Day, J. A., Caruso, J. A., Becker, J. S., and Dietze, H. J. (2000) Application of capUlary electrophoresis interfaced to double focusing sector field ICP-MS for nuchde abundance determination of lanthanides produced via spallation reactions in an irradiated tantalum target. J. Anal. At. Spectrom., 15, 1343-8. 

---