Y-spectroscopy

In principle, the same conclusion on the Nilsson orbital of the 9 Sr g.s. as obtained by the above mentioned T-spectroscopic work can already be drawn from a comparison of easily measurable gross 13-decay features (requiring 5 h measuring time for 13- and n-multiscaling, compared to 3 weeks for -y-spectroscopy) to predictions of our RPA shell model. In the... 

App68] Appel H 1968 Numerical tables for angular correlation computation in a-, / - and y-spectroscopy 3j-, 6j-, 9j-symbols, F- and T-coefficients, in Landolt-Bornstein, Numerical Data and Functional Relationships in Science and Technology, New Series, ed. H Schopper, ed in chief K.H Hellwege, Vol. 3 (Springer-Verlag, Berlin). 

Fujita, J. Shimura, Y. Spectroscopy and structures of metal chelate compounds. In Optical Rotary Dispersion and Circular Dichroism Nakamoto, K., McCarthy, P., Eds. Wiley, 1968 pp 156-215. 

In the Rf experiments [35] performed at the PSI Philips Cyclotron, 261Rf was produced in the Cm O, 5n) reaction at 100 MeV. The target contained 10% Gd enriched in 152 Gd to produce simultaneously short-lived Hf isotopes that were used to monitor the behavior of Hf and to perform yield checks by Y spectroscopy. Rf and Hf were transported by a He(KCl) gas jet and were collected for 90s by impaction inside ARCA II [7]. The deposit was dissolved in 200 pL 0.1 M HNO3/X M HF (x variable) and was fed onto the 1.6x8 mm cation-exchange column at a flow rate of 1 mL min 1. The effluent was evaporated to dryness as sample 1. In order to elute remaining Rf and Hf from the column, a second fraction of 200 pL 0.1 M HNO3/O.I M HF was collected to strip all group-4 elements from the column. The fraction was prepared as sample 2. 

Radionuclidic purity is determined by measuring the characteristic radiations emitted by individual radionuclides. Gamma emitters are distinguished from another by identification of their y energies on the spectra obtained from a Nal crystal or a Ge (germanium) detector. This method is called y spectroscopy. 

Apparatus. Ultraviolet, visible and near infrared spectra were recorded with a Cary 17 spectrophotometer, y spectroscopy was carried out with a Ge-Li detector and a Zoomax (Sein) multichannel analyzer. pH measurements were taken with an Aries 10000 (Tacussel) potentiometer, a spectroscopy was carried with a solid state a detector and a (Intertechnique) multichannel analyzer. 

Am (III] azide complexes. Distribution coefficients of Am (III] and Eu (III], present in the same solutions, were determined by Y spectroscopy. In conclusion, it appears that the azide complexes of actinides are more stable. 

The probability of y-interaction is so small in the small depletion depth of the surface barrier detectors that they are not very useful for y-spectroscopy. Large depleted volumes can be created by drifting lithium atoms into a silicon or germanium crystal. Lithium does not occupy a crystal site in the crystal, but is small enough to go into interstitial sites. The ease of ionization of Li to Li makes it a donor impurity. The lithium is drifted from one side of the crystal using an electric field. Its concentration at the "entrance" side becomes high and then decreases towards the other end of the crystal. The amount of lithium in the... 

Several authors have used ion-exchange methods to preconcentrate trace metals for further analysis from geothermal water 410) for x-ray determination 411, 412) for y-spectroscopy (475) and for atomic absorption spectroscopy (474, 475). For x-ray analysis, an attractive method for preconcentration is the use of ion-exchange resin-loaded paper (476-422). Although these methods often need slow filtration of the sample or several passes to obtain quantitative extraction of the metals, the sorbed material is presented in a convenient form for X ray, and low-concentration solutions and large sample volumes can be used. 

Rotational levels populated in the production of nobelium, measured with in-beam y spectroscopy, converted transitions dashed lines (Courtesy P. Reiter)... 

Step 2. After irradiation and appropriate radioactive decay of the sample and standards, these are measured on either a well-t3q)e or a coaxial large volume Ge(Li) y-ray detector system coupled to a PC-based y-spectroscopy system (explained in Sect. 6.3.4) to find out the energies of the y-rays in the observed spectrum (and hence the corresponding isotopes of the elements present in the sample). The distance of the sample fi om the detector (and hence the sohd angle) is adjusted depending on the coimt rate which should be about 100-500 counts per second. 

Fig. 6.3. y-spectroscopy system used in neutron activation analysis... 

After the experiments, the two phases were mechanically separated and weighed. The salt phase was crushed and dissolved in HNO3 (0.5 M). The metallic phase was heated up to its melting point and a sample was used for analysis. Uranium concentration was determined by UV-visible spectrophotometry. Concerning runs El, C and E2, the elements present in both phases were quantified by a and y spectroscopy (quantification of Pu and Am), X-ray fluorescence (quantification of U) and ICP-QMS (quantification ofNd). 

NOES Y spectroscopy has become especially nsefnl in the study of large molecules, such as proteins and polynucleotides. Very large molecules tend to tumble more slowly in solution, which means that nuclear Overhauser effect interactions have more time to develop. Small molecules tumble more quickly in solution the nuclei move past one another too qnickly to allow a significant development of dipolar interactions. The resnlt is that NOESY cross peaks may be too weak to be observed. 

---