摘要:

The possibilities of123I production with small accelerators will be discussed. Among the possible nuclear reactions the122Te(d, n)123I – and the123Te(p, n)123I reaction are of particular interest for those institutions, which do not run a cyclotron with particle energies for protons above 18 … 20 MeV. The use of TeO2as target material is advantaged over Te. The123I preparations contain reasonable amounts of130I and124I. The most “dangerous” impurity is130I due to its high energy gamma radiations. Nevertheless, high quality imagings may be obtained using medium – or high energy collimators loosing some of the advantages of123I. The proposed approach is the only way to make123I available for a number of institutions or countries running a small cyclotron and for which commerical123I is difficult or impossible to obtain for economical or geographical reasons.

ISSN:0021-1915    

DOI:10.1080/10256018808623981

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The current status in radioisotope and radiation application in the GDR is reviewed. Examples of new results are discussed in the most important industrial branches.

ISSN:0021-1915    

DOI:10.1080/10256018808623982

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Simple Rayleigh condensation and Rayleigh evaporation models for evaluating correlation between the isotopic composition of hydrogen and oxygen in meteoric water are analysed in terms of influences of accumulation of conversion products, of mixing of vapour and liquid phases, of extension or contraction of the system and of batch conversion. The effect of simultaneous conversion in both directions can be taken into account by introducing the relative amounts η of condensation and evaporation. The model yields m = 7.82 and q = 8.90 instead of the empirically found values m = 8.08 ± 0.80 and q = 9.57 ± 0.62 in the meteoric water line δD =mδ18O + q and a satisfactory understanding of the corresponding δD – δ18O correlations of the Northern and the Southern hemisphere with their different quantitative proportions of ocean and land masses.

ISSN:0021-1915    

DOI:10.1080/10256018808623983

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A non-contact measuring method on electrostatic potential by using α-ray ionization is proposed. In this method potential of a charged material is estimated from ionic current flowing through an ion collector attached with a small241Am source. As hade electrode surrounding the collector has a function of adjusting sensitivity and potential up to 50 kV was measured with precision of 1 kV.

ISSN:0021-1915    

DOI:10.1080/10256018808623984

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256018808623985

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Several protecting procedures were applied to ensure good operating performances of the universal99mTc generators based on fission produced99Mo. These procedures include the modifications of the adsorbent. Instead of 1 g of pure Al2O3the adsorption of99Mo is carried out on the multicomponent adsorbent containing the mixture of either Al2O3+ SiO2or Al2O3· Cu2++ SiO2. The protection by drying should ensure that the columns contain minimum of moisture during the growth period of99mTc. It was found experimentally that the best results are obtained when the ratio of alumina in the mixture was 15 ± 5 (wt.%) and content of copper 365 μg Cu2+/column. The comparison of efficiency and applicability of the used protecting procedures is also given.

ISSN:0021-1915    

DOI:10.1080/10256018808623986

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A 3-channel pulse counter for residence time measuring has been developed on the basis of the micro-computer KC 85/3. This system is characterized by modern conveniences compared with former residence time measuring devices. The technical parameters are comparable with usual radiation measuring assemblies.

ISSN:0021-1915    

DOI:10.1080/10256018808623987

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Interactions of252Cf fission neutrons at different locations within a buckled-up paraffin wax structure were studied. Some interesting physical parameters were deduced. These comprise, the build up factor, the age flux and the migration area. The diffusion lengths of neutrons in thermal and epithermal regions were also investigated.

ISSN:0021-1915    

DOI:10.1080/10256018808623988

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Experimental measurements have been carried out to determine neutron flux from a compact D-T neutron generator, Philips type, in tissue equivalent mediums (water, sea-water), NaCl as well was used. The measurements were carried out by using neutron activation foils as neutron detectors of successive threshold energies. The flux-dose conversion factors, as well as related quality factors averaged over the selected energy ranges, were used to determine equivalent dose and absorbed dose rates, respectively. The experimental and calculated results were found to be in a good agreement. Besides, dose build-up factors were determined. The contribution of thermal and intermediate neutron dose is relatively lower than that for fast neutrons.

ISSN:0021-1915    

DOI:10.1080/10256018808623989

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The concentrations of radioactive materials in black sand samples along the beach north to the Egyptian Delta were determined using γ-analysis and solid state nuclear track detector (SSNTD) techniques.232Th was found with appreciable concentrations which amounts to 250 ppm in Rosetta mouth sample. In addition, the gamma exposure dose rates were calculated.

ISSN:0021-1915    

DOI:10.1080/10256018808623990

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor