Nuclear orientation

Fig. 9.17. Energy level diagrams for 54Mn and 60Co (slightly simplified). These are the two decay favourite schemes used for nuclear orientation thermometry.

A significant source of error in nuclear orientation thermometers is due to the possible absorption of the radioactive emission in the cryostat, with a temperature increase as a consequence, low-intensity source must be used, with long counting periods to get a good statistics. 

Typical power values released by the radioactive substances used in nuclear orientation thermometers are ... 

An advantage of this technique, instead, is the good thermal contact with the (metallic) radioactive material, and, more important, the good thermal coupling between lattice and nuclear spins. Last, the j ray energy is usually quite high, and no special window in the cryostat is needed. Nuclear orientation thermometer is a primary thermometer. 

Comparisons among various thermometers and the nuclear orientation thermometer can be found in ref. [100-105] Further information may be obtained from ref. [97,106,107],... 

N.J. Stone, H. Postma eds. Low Temperature Nuclear Orientation, North-Holland, Amsterdam (1986)... 

Gamma-ray anisotropy or nuclear orientation thermometry OOl-l Spatial distribution of gamma-ray emission Spatial distribution related to Boltzmann factor for nuclear spin states Useful standard forT < IK... 

The method of alignment of nuclear moments has been used to study radioactive decay as a function of nuclear orientation. The aligning field in this case can be either an externally applied magnetic field or an internal... 

As a technique for measuring nuclear moments and investigating nuclear level structure, low temperature nuclear orientation has long been kept from areas of current activity in low energy nuclear physics by the half life limitation caused by needs of sample preparation and cooling to below 1 K. 

The combination of these three developments has led to the on-line nuclear orientation method (0LN0). A further advance of the technique has been the combination with NMR, which uses resonant rf perturbation of the nuclear polarization, yielding moment values to a few parts in 104. 

Fig. 1. Elements studied by low temperature nuclear orientation (magnetic and electric) and by NMR/ON.

This contribution concentrates on a discussion of some on-line techniques for ground state studies which are now under development and will be applied at ISOLDE in the near future. The plans for a nuclear-orientation set up at ISOLDE are outlined in the contribution to this symposium by N. Stone. 

LUE84] Proceedings of the Intern. Symposium on Nuclear Orientation and Nuclei far from Stability, Leuven 1984, ed. by B.l. Deutsch and L.. Vanneste, Hyperf. Interactions 22 (1985). 

One of the most important and most fascinating questions for a chemist is the one about the position of the superheavy elements in the Periodic Table of the Elements how well accommodates the Periodic Table these elements as transition metals in the seventh period. Do the rules of the Periodic Table still hold for the heaviest elements What is a valid architecture of the Periodic Table at its upper end The main body of information to answer this question from our today s knowledge of the chemistry of superheavy or transactinide elements is embraced between the two mainly "nuclear" oriented chapters at the beginning and at the end. 

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