A vast knowledge of nuclear data is available and is grouped under three headings, namely, nuclear structure, nuclear decay
and nuclear reaction data. Still newer aspects are under continuous investigation. Data measurements are done using a large
number of techniques, including the radiochemical method, which has been extensively worked out at Jülich. This method entails
preparation of high-quality sample for irradiation, isolation of the desired radioactive product from the strong matrix activity,
and preparation of thin source suitable for accurate measurement of the radioactivity. It is especially useful for fundamental
studies on light complex particle emission reactions and formation of low-lying isomeric states, both of which are rather
difficult to describe by nuclear model calculations. The neutron induced reaction cross section data are of practical application
in fusion reactor technology, particularly for calculations on tritium breeding, gas production in structural materials and
activation of reactor components. The charged particle induced reaction cross section data, on the other hand, are of significance
in medicine, especially for developing new production routes of novel positron emitters and therapeutic radionuclides at a
cyclotron. Both neutron and charged particle data also find application in radiation therapy. A brief overview of advances
made in all those areas is given, with major emphasis on nuclear reaction cross section data.
The separation of radioiodine was investigated using two wet chemical procedures, namely anion-exchange and solvent extraction.
Some factors affecting the separation, such as HCl, NaOH and tetrabutyl ammonium bromide (TBAB) concentrations, used solvents
ethyl acetate, benzene and carbon tetrachloride and different quaternary ammonium salts were studied. For each procedure the
optimum conditions were deduced. The separation of 123I was effected from proton-irradiated 123Te target under the optimized conditions of the two procedures. The yield of 123I obtained using the Dowex 21k anion-exchanger and tetrabutyl ammonium bromide solution as eluting agent was 88±3%; the radionuclidic
purity was high and the time needed was 60 minutes. In solvent extraction process using TBAB in ethyl acetate as the extracting
agent, the yield of 123I was low (47±3%), the radionuclidic purity was not as good as in the anion-exchange method, and the time needed was 150 minutes.
Therefore, the anionexchange method is preferable. A comparison of this wet chemical method of separation of 123I with the commonly used dry distillation method is given. The wet method appears to be more suitable when a 123Te metal target is used.
Nuclear data needs for fusion reactor design are briefly outlined. A summary is given of the radiochemical methods like precipitation,
co-precipitation, liquid-liquid extraction, ion-exchange and high-pressure liquid chromatography which have been applied in
the determination of cross-section data for (n, p), (n, n' p), (n, α), (n, n′p), (n, α), (n, n′ α), (n, t) and (n3He) reactions at 14 MeV, especially on potential wall materials and transmuted species. The measured data are discussed briefly.
A radiochemical method is described for the experimental determination of space dependent tritium production rate in a lithium
model blanket. Tritium was separated from Li by vacuum extraction and was determined quantitatively by gas phase β−-counting. A comparison of the experimental and computational results is given.
Radiochemical separation methods for K, Mn, Cu, Ga, Sr, Y, Nb, Ag, I, Ce, Eu, Lu and Pt, employing precipitation, adsorption,
distillation, solvent extraction or ion-exchange, as used in the investigations of rare nuclear reactions such as (n, t) and
(n,3He) at 14. 6 MeV, are described. For studying the (n, t) reaction at 23 MeV a method for the vacuum extraction and “low-level”
gas-phase counting of tritium is outlined. The measured nuclear reaction cross-section data are discussed briefly.
Authors:S. Kandil, B. Scholten, K. Hassan, H. Hanafi, and S. Qaim
The radiochemical separation of 88Y from proton irradiated natSrCO3 and alpha-particle irradiated natRbCl, of 86Y from proton irradiated 86SrCO3, and of 87Y from alpha-particle irradiated natRbCl were studied at no-carrier-added levels by two techniques, namely, ion-exchange chromatography using Dowex 50W-X8 and
Dowex 21K resins, and solvent extraction using HDEHP. Out of all those methods, the ion-exchange chromatography using Dowex
50W-X8 (cation-exchanger) was found to be the best: the separation yield was high, the chemical impurity in the separated
radioyttrium (inactive Sr or Rb) was low (0.5 μg) and the final product was obtained in the form of citrate. The optimized
separation method using Dowex 50W-X8 was applied in practical production of 86Y and 88Y via proton irradiations of 86SrCO3 and natSrCO3, respectively, at 16 MeV as well as of 87Y and 88Y via α-particle irradiation of natRbCl at 26 MeV. The tangible experimental yields of 86Y and 87Y amounted to 150 and 5.7 MBq/μA·h, respectively. The yields of 88Y obtained were 0.06 MBq/μA·h and 1 MBq/μA·h for alpha-particle and proton irradiations, respectively. Each yield value corresponds
to more than 70% of the respective theoretical value.
Authors:R. Weinreich, S. Qaim, H. Michael, and G. Stöcklin
The advantages of high energy cyclotrons as compared to small compact cyclotrons for the production of special radionuclides
are outlined. The routine production of123I (T=13.3 h) and28Mg (T=21.1 h) by means of high energy nuclear reactions at the Jülich Isochronous Cyclotron is described. The reaction127I(d,6n)123
123I at 78 to 64 MeV is used for the production of123I with thick target yields of 8 mCi/μAh and high radionuclidic purity. The practical experience in the application of this
process, which is well suited for the production of Na123I and for123Xe-exposure labelling techniques, is reported.28Mg is produced by the27Al(α, 3p)28Mg reaction at Eα=140 to 30 MeV with thick target yields of 40 μCi/μAh. The carrier-free28Mg is separated from the matrix activities by coprecipitation and anion exchange with chemical yields of 80%.
Authors:M. Shehata, B. Scholten, I. Spahn, S. Qaim, and H. Coenen
The radiochemical separation of radiogallium from radiogermanium was studied using ion-exchange chromatography (Amberlite
IR-120) and solvent extraction (Aliquat 336 in o-xylene). Both Amberlite IR-120 and Aliquat 336 in o-xylene have been used for the first time in separations involving radiogallium and radiogermanium. For tracer studies the
radionuclides 68Ge (t1/2 = 270.8 days), 69Ge (t1/2 = 39 h) and 67Ga (t1/2 = 78.3 h) were used. They were produced by the nuclear reactions natGa(p,xn)68,69Ge and natZn(p,xn)67Ga, respectively, and separated from their target materials in no-carrier-added form. Several factors affecting the separation
of radiogallium from radiogermanium were studied and for each procedure the optimum conditions were determined. The solvent
extraction using Aliquat 336 was found to be better. The separation yield of radiogallium was >95%, the time of separation
short, the contamination from radiogermanium <0.008% and the final product was obtained in 0.5 M KOH. This method was adapted
to the separation of n.c.a. 68Ga from its parent n.c.a. 68Ge. The quality of the product thus obtained is discussed.
Authors:M. Shehata, B. Scholten, I. Spahn, H. Coenen, and S. Qaim
A method for the separation of no-carrier-added arsenic radionuclides from the bulk amount of proton-irradiated GeO2 targets as well as from coproduced radiogallium was developed. The radionuclides 69Ge and 67Ga produced during irradiation of GeO2 were used as tracers for Ge and Ga in the experiments. After dissolution of the target the ratio of As(III) to As(V) was
determined via thin layer chromatography (TLC). The extraction of radioarsenic by different organic solvents from acid solutions
containing alkali iodide was studied and optimized. The influence of the concentration of various acids (HCl, HClO4, HNO3, HBr, H2SO4) as well as of KI was studied using cyclohexane. The optimum separation of radioarsenic was achieved using cyclohexane with
4.75 M HCl and 0.5 M KI and its back-extraction with a 0.1% H2O2 solution. The separation leads to high purity radioarsenic containing no radiogallium and <0.001% [69Ge]Ge. The overall radiochemical yield is 93 ± 3%. The practical application of the optimized procedure in the production
of 71As and 72As is demonstrated and batch yields achieved were in the range of 75–84% of the theoretical values.
Authors:S. Kandil, B. Scholten, Z. Saleh, A. Youssef, S. Qaim, and H. Coenen
The radiochemical separation of no-carrier-added zirconium from proton irradiated yttrium was studied by two techniques, namely,
ion-exchange chromatography using Dowex 50W-X8 and Dowex 21K resins, and solvent extraction using HDEHP and TPPO, the latter
reagent being employed for the first time for separation of radiozirconium from bulk of yttrium. Out of all those techniques,
the solvent extraction using TPPO was found to be the best: the separation yield of radiozirconium was >97%, the time of separation
was short, the contamination from the long-lived 88Y activity was low (10−4%) and the final product was obtained in the form of oxalate. The production of 89Zr and 88Zr of high radionuclidic and chemical purity via irradiation of yttrium targets with protons of energies 12 and 20 MeV, respectively,
is described. The experimental yields of the two radionuclides were found to be 28 MBq/μA·h and 1.63 MBq/μA·h, respectively.
Each value corresponds to about 80% of the respective theoretical yield.