Tritium-containing targets

Production-Scale Processing. The tritium produced by neutron irradiation of Li must be recovered and purified after target elements are discharged from nuclear reactors. The targets contain tritium and He as direct products of the nuclear reaction, a small amount of He from decay of the tritium and a small amount of other hydrogen isotopes present as surface or metal contaminants. 

It should be noted that commercial neutron generators are also easily adopted to the generation of 2.8 MeV neutrons produced by the 2H(2H,w)3He reaction. In most cases it is merely necessary to replace the tritium target with one containing occluded deuterium. The neutron yield from this reaction is much less than for the D—T reaction and the useful flux is often not much greater than could be obtained by use of isotopic sources. About 35 elements have been found to possess reasonably high (n,n y) or (n,y) cross sections for 2.8 MeV neutrons 41>. Since the 8 most common elements in the earth s crust are not among those readily activated, there is some potential application of 2.8 MeV neutrons in analyses for certain elements in minerals and ores, where major element interferences via 14 MeV activation may be a problem. 

Scheme 3 Affinity-based probes targeting MMPs, from studies by Dive et al. [54]. (a) Photoreactive A/BP containing a tritium label. ZBG zinc binding group, (b) Possible constructs formed between hMMP-12 and 21 after photolysis proposed by Dive et al. [55]. (c) Structures of A/BPs with or without a photophore for pull-down of active MMPs...

Nuclear fusion provides the energy of our sun and other stars. Development of controlled fusion as a practical source of energy requires methods to initiate and contain the fusion process. Here a very powerful laser beam has initiated a fusion reaction in a 1-mm target capsule that contained deuterium and tritium. In a 0.5-picosecond burst, 10 neutrons were... 

As we noted in Section 21.6, energy can be obtained by combining light nuclei into a heavier nucleus by nuclear fusion. Such fusion reactions have been observed in the laboratory by means of bombardment using particle accelerators. Deuterons (iH nuclei), for example, can be accelerated toward targets containing deuterium (iH atoms) or tritium (iH atoms). The reactions are... 

The pulsed-neutron generator consists principally of an ion source for the production of deuterons in a pulsed beam, and focusing and accelerating electrodes to focus and accelerate this beam to strike the target. The target contains deuterium or tritium, so we obtain neutrons from the reaction - He + n + 3.3 MeV or - He + n + 17.6 MeV. 

The amount of tritium taken up in a target containing over 4 mg of zirconium is determined within 10%, by standard gas techniques checked against ion chamber measurements. The amount in a target containing less than 4 mg of zirconium is measured within 20% by the ion chamber method only. 

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