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Cross sections of proton-induced nuclear reactions on enriched $$^{\mathrm {86}}$$ 86 Sr target were measured by the activation technique up to proton energies of 44 MeV. The isomeric cross-section ratios for $$^{\mathrm {86m,g}}$$ 86 m , g Y and $$^{\mathrm {85m,g}}$$ 85 m , g Y as a function of projectile energy were deduced from their measured data. The present experimental data for the nuclear reaction products, namely $$^{\mathrm {86m}}$$ 86 m Y, $$^{\mathrm {86g+xm}}$$ 86 g + xm Y, $$^{\mathrm {85m}}$$ 85 m Y, $$^{\mathrm {85g}}$$ 85 g Y, $$^{\mathrm {84}}$$ 84 Rb and $$^{\mathrm {83}}$$ 83 Rb were compared with the results of nuclear model calculations using the code TALYS, which combines the statistical, precompound, and direct interactions. In general, the experimental cross-section data as well as the isomeric cross-section ratios are reproduced well by the model calculations, provided the input model parameters are properly chosen and the level structure of the product nucleus is thoughtfully considered. The quality of the agreement between experimental data and model calculations was numerically quantified. For products formed via emission of a light complex particle as well as multi-nucleons (e.g., $$\alpha $$ α and 2p2n), the contribution of the latter process starts increasing when its energy threshold is crossed.

Integral cross sections of the reactions 24Mg(n,p)24Na, 27Al(n,p)27Mg, 27Al(n,α)24Na, 58Ni(n,d + np)57Co and 60Ni(n,p)60Co were measured for the first time using the fast neutron spectrum of a TRIGA reactor extending from 0.5 to 20 MeV. The values obtained in this work were comparable with the recommended values for a pure 235U prompt fission spectrum. The measured integral value was utilized for integral test of excitation function of each reaction given in some data libraries, namely ENDF/B-VIII.0, TENDL-2017, IRDFF-1.05 and ROSFOND-2010. The integral measurements are generally consistent with the integrated values within 5 %, except for a few cases, e. g. the reaction 60Ni(n,p)60Co, where the data libraries appear to need improvement.

We have deduced the emission probability of the 447-keV $\ensuremath{\gamma}$ ray from the $\ensuremath{\varepsilon}+{\ensuremath{\beta}}^{+}$ decay of $^{137}\mathrm{Ce}^{g}$ (9.0 h) relative to that of the 254-keV $\ensuremath{\gamma}$ ray from the $^{137}\mathrm{Ce}^{m}$ (34.4 h) decay in transient equilibrium. The time-dependent factor in transient equilibrium was applied following the Bateman equation for a radioactive decay chain. The isotope was produced via the $^{139}\mathrm{La}(p,3n)^{137}\mathrm{Ce}^{m,g}$ reaction by bombarding ${}^{\mathrm{nat}}\mathrm{La}$ with a proton beam from the 88-in. cyclotron at Lawrence Berkeley National Laboratory. $\ensuremath{\gamma}$-ray intensities were measured using an HPGe detector. The emission probability for the 447-keV $\ensuremath{\gamma}$ ray deduced in this work is 1.21(3) (that is 1.21 \ifmmode\pm\else\textpm\fi{} 0.03) per hundred parent decays, which differs significantly from an earlier published value of 2.24(10). We identify the source of this discrepancy to be an incorrect use of the time-dependent factor. Additionally, we have deduced the emission probability of the 504-keV $\ensuremath{\gamma}$ ray from the decay of $^{85}\mathrm{Y}^{g}$ (2.68 h) relative to that of the 232-keV $\ensuremath{\gamma}$ ray from the $^{85}\mathrm{Sr}^{m}$ (1.127 h) decay in transient equilibrium. The isotope was produced via the $^{86}\mathrm{Sr}(p,2n)^{85}\mathrm{Y}^{g}$ reaction by bombarding $^{86}\mathrm{SrCO}_{3}$ with a proton beam at the same facility. The study confirms the assumption of the time-dependent correction for recommending the emission probability of the 504-keV $\ensuremath{\gamma}$ ray in the literature. Our work highlights the importance of explicit description by authors of any time-dependent correction they have made when reporting $\ensuremath{\gamma}$-ray intensities for nuclides in transient equilibrium. The need and significance of accurate and precise decay data of $^{137}\mathrm{Ce}^{g}$ and $^{85}\mathrm{Y}^{g}$ in basic science and medicine is briefly outlined.

89Zr (T1/2 = 3.27 d) is an important β+-emitting radionuclide of zirconium used in immuno PET. The excitation functions of the 89Zr (T1/2 = 3.27 d) is an important β+-emitting radionuclide of zirconium used in 89Y(d,2n)89Zr and 89Y(p,n)89Zr reactions were analyzed to deduce the optimum conditions for the high purity production of 89Zr. The nuclear model codes ALICE-IPPE, EMPIRE 3.2 and TALYS 1.9 were used to check the consistency and reliability of the experimental data. A polynomial fit to the chosen data for each reaction gave the excitation function, which was then used for the integral yield calculation of the product. The amount of the major radioactive impurity 88Zr was precisely analyzed for both the proton and the deuteron induced reactions on the 89Y target.

The excitation functions of the (54)Fe(d,n)(55)Co, (56)Fe(p,2n)(55)Co and (58)Ni(p,α)(55)Co reactions were analyzed with relevance to the production of the β(+)-emitter (55)Co (T½=17.53 h), a promising cobalt radionuclide for PET imaging. The nuclear model codes ALICE-IPPE, EMPIRE and TALYS were used to check the consistency of the experimental data. The statistically fitted excitation function was employed to calculate the integral yield of the product. The amounts of the radioactive impurities (56)Co and (57)Co were assessed. A comparison of the three investigated production routes is given.

The $\Theta_{eff}/\Theta_{rig}$ parameter of the spin distribution of the level density was determined for 61 nuclei covering the mass range of 44 to 200. The experimental isomeric cross-section ratios for 25 isomeric pairs were compared with the model calculation to find the best fit to the experimental data. The model calculations were carried out with the TALYS code using the BSFG model for the level density. The reduced $\chi ^2$ values were calculated to describe the deviation of the experimental data from the model calculation. An $\eta_d $ was introduced calculating the $\Theta_{eff}/\Theta_{rig}$ value from the low energy discrete levels of the nucleus. The $\eta /\eta_d $ values seem to be independent of the mass number, their average value near to one. The $\eta /\eta_d $ values also seem to be independent of the average excitation energy in the continuum, indicating that $\eta $ is independent of the excitation energy. The mass number and (N-Z) dependence of the $\eta $ values were studied. The $\eta $ values for the nuclei with odd mass number show an exponential decrease as a function of A or (N-Z). The $\eta $ values for the odd-odd type of nuclei appear to be constant, near one, up to the mass number 110 or (N-Z) of 13. Above these values, the $\eta $ values show exponential decrease. The $\eta $ values for even-even type nuclei decrease exponentially up to A equal to 142 or (N-Z) equal to 20. The values are lower than those for the nearby odd-odd type nuclei. The $\eta $ values increase for nuclei with A between 142 and 156 and (N-Z) between 20 and 28, and they finally reach the value of odd-odd type systematics., Comment: 67+3 pages, 52+2 figures. Calculations with EMPIRE have been added to Section IV.3

The proton induced nuclear reactions on 86Sr, 88Sr and natZr were investigated for the production of 86Y. The literature data were compared with the results of nuclear model calculations using the codes ALICE-IPPE, TALYS 1.6 and EMPIRE 3.2. The thick target yields of 86Y were calculated from the recommended excitation functions. Analysis of radioyttrium impurities was also performed. A comparison of the various production routes showed that for medical applications of 86Y, the reaction 86Sr(p,n)86Y is the method of choice, which gives efficient yield with minimum impurities.

Cross section data for formation of the medically important radionuclide 61 Cu ( T ½ =3.33 h) in proton and deuteron induced reactions on enriched 64 Zn and in 3 He - and α - particle induced reactions on 59 Co were analyzed by using the nuclear model calculational codes, EMPIRE and TALYS. A well-defined statistical procedure was then employed to derive the recommended excitation functions, and therefrom to obtain integral yields. A comparison of major production routes of 61 Cu was done.

Excitation functions were calculated for the α-particle induced reactions

Neutron activation analysis is generally carried out with reactor neutrons using the (n,γ) reaction. However, for cases where the (n,γ) reaction products have unsuitable decay properties, or if due to low cross-section the process is not very specific, activation with 14 MeV neutrons and identification of the (n,x) reaction products may be of advantage. This is particularly true for the light elements where fast neutron activation is often considerably more specific. Thus, with thermal neutrons only macro amounts of nitrogen and oxygen can be determined via the 15N(n,γ)16N and 18O(n,γ)19O reactions, respectively, whereas use of 14 MeV neutrons enables the detection of parts per million amounts of those two elements via the reactions 14N(n,2n)13N and 16O(n,p)16N, respectively. Similarly, fluorine, sodium, and silicon can be conveniently determined using fast neutron activation via the reactions 19F(n,2n)18F, 23Na(n,α)20F and 28Si(n,p)28Al, respectively. In the medium and heavy mass regions as well, in several specific cases, 14 MeV neutron activation analysis may be advantageous and more convenient than thermal neutron activation analysis. The determination of iron, niobium, and thallium via the reactions 56Fe (n,p)56Mn, 93Nb(n,2n)92Nb, and 203Tl(n,2n)202Tl, respectively, constitute some typical examples.

A novel anion-exchange chromatographic method for separation of radioiodine from an antimony target irradiated with 3He- or α-particles was developed, with separation yield of radioiodine amounting to 90 ± 5 % and its decontamination factor from the Te and Sb radionuclides to ~104. The optimized separation method developed was then applied to the production of 124I via the 121Sb(α,n)124I process using a highly enriched 121Sb target. Quality control tests showed that the separated 124I occurred >99 % as iodide and the longer lived impurities 126I and 125I amounted to 0.16 % and

Excitation function of the reaction $^{60}\mathrm{Ni}(p,\ensuremath{\gamma})^{61}\mathrm{Cu}$ was measured via the activation technique in the energy range of 1.3--16.0 MeV using a low-energy accelerator and a small cyclotron. The results are comparable to those previously obtained via prompt \ensuremath{\gamma} counting. In addition excitation functions of the more common competing $^{60}\mathrm{Ni}(p,n)^{60}\mathrm{Cu}$ and $^{60}\mathrm{Ni}(p,\ensuremath{\alpha})^{57}\mathrm{Co}$ reactions were also measured. Theoretical calculations on proton-induced reactions on $^{60}\mathrm{Ni}$ were performed using the nuclear model code talys. The results suggest that near the threshold of the reaction the compound nucleus mechanism dominates. Thereafter the contribution of direct interactions becomes rather strong, especially between 4 and 6 MeV, i.e., just below the threshold of the $^{60}\mathrm{Ni}(p,n)^{60}\mathrm{Cu}$ reaction. The cross section at the maximum of the excitation function of each of the three reactions, namely, $^{60}\mathrm{Ni}(p,\ensuremath{\gamma})^{61}\mathrm{Cu},^{60}\mathrm{Ni}(p,n)^{60}\mathrm{Cu}$, and $^{60}\mathrm{Ni}(p,\ensuremath{\alpha})^{57}\mathrm{Co}$, amounts to 2, 320, and 85 mb, respectively. The $(p,n)$ reaction is thus the most commonly occurring process, and the $(p,\ensuremath{\gamma})$ reaction is the weakest, possibly due to higher probability of particle emission than \ensuremath{\gamma}-ray emission from the highly excited intermediate nucleus $^{61}\mathrm{Cu}$ formed in the interaction of a proton with the target nucleus $^{60}\mathrm{Ni}$.

Experimentally investigated nuclear reactions for production of no-carrier-added 77Br and 77Kr were critically surveyed. The survey covered nine reactions for the formation of 77Br and six reactions for 77Kr. Both radionuclides are simultaneously produced in many of the studied nuclear processes. The experimental data were compared with the results of nuclear model calculations based on the computer code ALICE-IPPE and the third version of T ALYS-based E valuated N uclear D ata L ibrary, TENDL-2010. Good agreement was found over extended energy regions for the p-, 3He- and α-particle induced reactions on several target materials. In case of d-induced reactions, however, considerable discrepancies were noted between the experimental and theoretical data. The concordant sets of experimental cross section data for each reaction were fitted by a polynomial function to obtain a trend curve. From the thus obtained trend curves the yields of both 77Br and 77Kr were calculated. A discussion of suitable production routes is given.

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 (t 1/2 = 270.8 days), 69Ge (t 1/2 = 39 h) and 67Ga (t 1/2 = 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

Cross section data were evaluated for the production of the medically important positron emitter (124)I (T(1/2)=4.18d) via (3)He- and α-particle induced reactions on Sb isotopes. The consistency in the measured data available in the literature was checked against the cross section calculations of three nuclear model codes (i.e. STAPRE, EMPIRE and TALYS). The recommended excitation functions obtained by a statistical procedure were used to derive the integral yields. An assessment of the (124)I yields and associated radioisotopic impurities suggests that the (123)Sb(α,3n)(124)I process over the energy range of E(α)=45 → 32 MeV could be of potential interest for the production of (124)I.

Excitation functions of the reactions (55)Mn(p,n)(55)Fe, (55)Mn(p,x)(54)Mn and (55)Mn(p,x)(51)Cr were measured from their respective thresholds up to 18 MeV in the first case and up to 45 MeV in the latter two cases, using the conventional stacked-foil technique. The radioactivity of (55)Fe was determined via high resolution X-ray spectrometry and of other radionuclides via high resolution γ-ray spectrometry. Nuclear model calculations were performed using the codes ALICE-IPPE, EMPIRE and TALYS. In some cases, good agreement was found between the experimental and theoretical data while in others considerable deviations were observed. From the experimental data the expected integral yields of the three investigated radionuclides were calculated.

Cross-section data for the production of medically important radionuclide (124)I via five proton and deuteron induced reactions on enriched tellurium isotopes were evaluated. The nuclear model codes, STAPRE, EMPIRE and TALYS, were used for consistency checks of the experimental data. Recommended excitation functions were derived using a well-defined statistical procedure. Therefrom integral yields were calculated. The various production routes of (124)I were compared. Presently the (124)Te(p,n)(124)I reaction is the method of choice; however, the (125)Te(p,2n)(124)I reaction also appears to have great potential.

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

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 Julich. 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 dose distribution in proton therapy is mainly due to primary particles and secondary electrons. The contribution of short-lived β + emitters formed in the interactions of protons with the light mass elements C, N and O has hitherto not been considered. We estimated the formation of 11 C, 13 N and 15 O in irradiation of tissue with 200 MeV protons. The integral yields at 150 MeV were compared with a literature phantom measurement. The results for 11 C and 15 O agreed very well; for 13 N, however, appreciable deviation was observed. The activities were also calculated in the region around the Bragg peak as well as over the path length after entrance of the beam. Dose calculations were then done using the medical internal radiation dose (MIRD) formalism. Furthermore, a dose calculation was simulated for a 150 MeV proton beam (2 nA, 2 min) in a brain tumour. The dose deposited by the positron emitters in the Bragg peak region was found to be about 1.5 mGy, i.e. less than 1% of the dose estimated from the electronic interactions of protons. The absorbed dose in the whole brain amounted to 5.5 mGy.

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.

We present the first measured and interpreted excitation functions for three nuclear reactions on the radioactive target nucleus 99Tc over the energy range from threshold to 20.6 MeV. Excitation functions for the 99Tc( n , n ′ γ )99mTc, 99Tc( n , p )99Mo, and 99Tc( n , α )96Nb reactions were measured using the activation method. High-resolution γ-ray spectroscopy was used requiring special attention to suppress Bremsstrahlung. The irradiated samples consisted of pressed pellets of metallic 99Tc in Al-capsules. Quasi mono-energetic neutrons were produced via the 3H( p , n )3He, 2H( d , n )3He, and 3H( d , n )4He reactions. The neutron fluence was monitored via the well-known 115In( n , n ′ )115mIn, 27Al( n , α )24Na, 27Al( n , p )27Mg, 56Fe( n , p )56Mn, and 93Nb( n , 2 n )92mNb standard reactions. Statistical model calculations incorporating precompound effects were performed for all the measured reaction channels using two different codes, namely TALYS and STAPRE. Good agreement was obtained for the reactions in which a charged particle was emitted and for the excitation of the isomer in inelastic scattering, above 5 MeV.

Excitation functions were determined by the stacked-foil and induced radioactivity measurement technique for the reactions (100)Ru(alpha,n)(103)Pd, (101)Ru(alpha,2n)(103)Pd, (101)Ru((3)He,n)(103)Pd, and (102)Ru((3)He,2n)(103)Pd, producing the therapeutic radionuclide (103)Pd, and for the reactions (101)Ru((3)He,x)(101 m)Rh(Cum) and (102)Ru((3)He,x)(101 m)Rh(Cum), producing the medically interesting radionuclide (101 m)Rh. Data were also measured for the reactions (101)Ru((3)He,pn+d)(102 m,g)Rh, (102)Ru((3)He,p2n+dn+t)(102 m,g)Rh, (101)Ru((3)He,x)(101 g)Rh(Cum), (102)Ru((3)He,x)(101 g)Rh(Cum), (101)Ru((3)He,3n)(101)Pd, (102)Ru((3)He,4n)(101)Pd, (101)Ru((3)He,4n)(100)Pd, and (101)Ru((3)He,p3n+d2n+tn)(100)Rh, producing other palladium and rhodium isotopes/isomers. The energy ranges covered were up to 25 MeV for alpha-particles and up to 34 MeV for (3)He ions. The radioactivity of the radionuclide (103)Pd induced in thin metallic foils of the enriched ruthenium isotopes was measured by high-resolution X-ray spectrometry and the radioactivities of other radionuclides by gamma-ray spectrometry. The integral thick target yields of the radionuclide (103)Pd calculated from the excitation functions of the first four of the above-named reactions amount to 960, 1050, 50, and 725 kBq/microAh, respectively, at the maximum investigated energies of the incident particles. The integral thick target yields of the radionuclide (101 m)Rh amount to 16.1 and 2.9 MBq/microAh for (101)Ru and (102)Ru targets, respectively, at 34 MeV energy of incident (3)He ions. The integral yields of the other observed radionuclides were also deduced from the excitation functions of the above-mentioned respective nuclear reactions. The excitation functions and integral yields of some rare reaction products were also determined. The experimental excitation functions of some reactions are compared with the predictions of nuclear model calculations. In general, good agreement was obtained.

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.

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.

Excitation functions for the formation of the arsenic radionuclides (71)As, (72)As, (73)As and (74)As in the interaction of protons with (nat)Ge were measured from the respective threshold energy up to 100 MeV. The conventional stacked-foil technique was used and the needed thin samples were prepared by sedimentation. Irradiations were done at three cyclotrons: CV 28 and injector of COSY at Forschungszentrum Jülich, and Separate Sector Cyclotron at iThemba LABS, Somerset West. The radioactivity was measured via high-resolution gamma-ray spectrometry. The measured cross section data were compared with the literature data as well as with the nuclear model calculations. In both cases, the results generally agree but there are discrepancies in some areas, the results of nuclear model calculation and some of the literature data being somewhat higher than our data. The integral yields of the four radionuclides were calculated from the measured excitation functions. The beta(+) emitting nuclide (72)As (T(1/2)=26.01 h) can be produced with reasonable radionuclidic purity ((71)As impurity:10%) over the energy range E(p) = 18--8 MeV; the yield of 93 MBq/microAh is, however, low. The radionuclide (73)As (T(1/2)=80.30 d), a potentially useful indicator in environmental studies, could be produced with good radionuclidic purity ((74)As impurity:11%) over the energy range E(p) = 30 --18 MeV, provided, a decay time of about 60 days is allowed. Its yield would then correspond to 2.4 MBq/microAh, and GBq amounts could be produced when using a high current target.

Activation cross sections of deuteron induced nuclear reactions on 169 Tm were measured up to 20 MeV by using the stacked-foil technique. Special emphasis was on production of the internal radiotherapy related radionuclide 169 Yb. No earlier experimental cross-section data on deuteron induced reactions on 169 Tm were found in the literature. The experimental data were compared with the results of the nuclear model codes ALICE-IPPE and EMPIRE-II. The integral yield of the 169 Tm( d , 2n ) 169 Yb reaction was deduced over the optimum energy range E d =20→9 MeV. At 3.8 MBq/μA·h the yield is lower than that available from the commonly used 168 Yb( n , γ ) 169 Yb reactor method but on the other hand, it is higher than the yields from the earlier investigated 169 Tm( p , n ) 169 Yb and nat Er( α , x ) 169 Yb reactions.

Excitation functions and production rates are presented for various Ce radionuclides formed in the bombardment of 141Pr and natLa with protons. Measurements were performed for 141Pr + p up to 100 MeV and for natLa + p up to 20 MeV. The possibility is investigated to utilize tandem targetry for the production of no-carrier-added 139Ce of high radionuclidic purity, having a Pr target in the higher energy slot followed by a La target in a lower energy slot. The results of this work are also compared with previous literature experimental data, where available, as well as with predictions by means of the geometry-dependent hybrid (GDH) model as implemented in the code ALICE-IPPE.

The recently reported cross-section data for the production of 82Sr via the natRb(p,xn) 82Sr process were evaluated. For the natRb(p,xn) 85Sr process, cross-sections were measured experimentally over the proton energy range of 25-45 MeV, a region where very few data existed. An evaluation of the recently published data on the formation of 85Sr was then also performed. From the recommended data curves, the integral yields of the desired radionuclide 82Sr and the impurity 85Sr were calculated. Yields were also determined experimentally over several energy ranges using thick natRbCl targets. The experimental and calculated yields were found to be in agreement within 15%. These integral tests add confidence to the evaluated cross-section data. For the production of 82Sr, an incident proton energy of 60 MeV or above is recommended; the 85Sr impurity then corresponds to

The excitation functions of the (54)Fe(d,n)(55)Co, (56)Fe(p,2n)(55)Co and (58)Ni(p,α)(55)Co reactions were analyzed with relevance to the production of the β(+)-emitter (55)Co (T½=17.53 h), a promising cobalt radionuclide for PET imaging. The nuclear model codes ALICE-IPPE, EMPIRE and TALYS were used to check the consistency of the experimental data. The statistically fitted excitation function was employed to calculate the integral yield of the product. The amounts of the radioactive impurities (56)Co and (57)Co were assessed. A comparison of the three investigated production routes is given.

The proton induced nuclear reactions on (86)Sr, (88)Sr and (nat)Zr were investigated for the production of (86)Y. The literature data were compared with the results of nuclear model calculations using the codes ALICE-IPPE, TALYS 1.6 and EMPIRE 3.2. The thick target yields of (86)Y were calculated from the recommended excitation functions. Analysis of radioyttrium impurities was also performed. A comparison of the various production routes showed that for medical applications of (86)Y, the reaction (86)Sr(p,n)(86)Y is the method of choice, which gives efficient yield with minimum impurities.

The irradiation facility at an old medical cyclotron (Ep=17 MeV; Ed=10 MeV) was upgraded by extending the beam line and incorporation of solid state targetry. Tests performed to check the quality of the available beam are outlined. Results on nuclear data measurements and improvement of radiochemical separations are described. Using solid targets, with the proton beam falling at a slanting angle of 20°, a few radionuclides, e.g. 75Se, 120I, 124I, etc. were produced with medium currents (up to 20 µA) in no-carrier-added form in quantities sufficient for local use. The extended irradiation facility has considerably enhanced the utility of the medical cyclotron.

The non-pure positron-emitting iodine isotope (120)I (T(1/2)=81 min) is a short-lived alternative to (124)I. (120)I has a positron abundance more than twice that of (124)I and a maximum positron energy of 4 MeV. This study was undertaken to evaluate and characterise the qualitative and quantitative PET imaging of (120)I.(120)I was produced via the (120)Te(p,n) reaction on highly enriched (120)Te. The measurements were done with the Siemens scanner HR+ and the 2D PET scanner GE PC4096+. A cylinder containing three cold inserts and a phantom resembling a human brain slice were used to evaluate half-life, positron abundance and background correction. To analyse the image resolution, a -mm tube placed in water was filled with (120)I and (18)F. Comparisons with (18)F, (124)I and (123)I (measured with SPECT) were made using the Hoffman 3D brain phantom.The half-life of 81.1 min was reproduced by the PET measurements. The PET-based positron abundance ranged from 47.9% to 55.0%. The reconstructed image resolution found with the HR+ was 5.4 mm FWHM (12.3 mm FWTM), in contrast to 4.6 mm (8.6 mm) when using (18)F. Erroneous positive and negative numbers of radioactivity found in the cold inserts became nearly zero when the background of gamma-coincidences was corrected for. Images of the Hoffman phantom were inferior to those obtained when (18)F or (124)I was applied but superior to the (123)I-SPECT images.Our data show that (120)I of high radionuclidic purity can be regarded as a suitable nuclide for the PET imaging of radioiodine-labelled pharmaceuticals.

Excitation functions of the reactions (nat)Sb((3)He,xn)(124,123,121)I were measured from their respective thresholds up to 35 MeV, with particular emphasis on data for the production of the medically important radionuclide (124)I. The conventional stacked-foil technique was used. From the experimental data the theoretical yields of the three investigated radionuclides were calculated. The yield of (124)I over the energy range E9(30He) = 35 --> 13 MeV amounts to 0.95 MBq/microA h. The radionuclidic impurities are discussed. A comparison of (3)He- and alpha-particle-induced reactions on antimony for production of (124)I is given. The alpha-particle-induced reaction on enriched (121)Sb and the (3)He-particle-induced reaction on enriched (123)Sb would lead to comparable (124)I yields, but the level of impurities in the latter case would be somewhat higher.

Excitation functions of the reactions (nat)Sb(alpha,xn)(123,124,125,126)I and (121)Sb(alpha,xn)(123,124)I were measured from their respective thresholds up to 26 MeV, with particular emphasis on data for the production of the medically important radionuclide (124)I. The conventional stacked-foil technique was used, and the samples for irradiation were prepared by a sedimentation process. The measured excitation curves were compared with the data available in the literature. From the experimental data the theoretical yields of the investigated radionuclides were calculated as a function of the alpha-particle energy. The calculated yield of (124)I from the (nat)Sb(alpha,xn)(124)I process over the energy range E(alpha) = 22-->13 MeV amounts to 1.02 MBq/microA x h and from the (121)Sb(alpha,n)(124)I reaction over the same energy range to 2.11 MBq/microA x h. The radionuclidic impurity levels are discussed. Use of (nat)Sb as target material would not lead to high-purity (124)I. Using highly enriched (121)Sb as target, production of (124)I of high radionuclidic purity is possible; the batch yield, however, is low.

The potential tumor seeking MRI contrast agent MnTPPS(4) was labelled with the positron emitting nuclide (51)Mn in no-carrier-added (n.c.a.) form. The complex formation kinetics were investigated and the apparent rate constants were determined under pseudo-first-order conditions. The derived bimolecular rate constants gave the Arrhenius parameters E(A)=84 kJ mol(-1) and A=2 x 10(12)s(-1)M(-1). Optimum labelling conditions were derived (radiochemical yields >99% possible, effective yields about 32%). Separation and purification of n.c.a. (51)MnTPPS(4) were performed for potential human use. All impurities were

Excitation functions were measured by the stacked-foil technique for proton induced reactions on carbon, nitrogen and oxygen leading to the formation of the short-lived positron emitters (11)C (T(1/2) = 20.38 min) and (13)N (T(1/2) = 9.96 min). The energy region covered extended up to 200 MeV. The product activity was measured non-destructively via gamma-ray spectrometry. A careful decay curve analysis of the positron annihilation radiation was invariably performed. The experimental results were compared with theoretical data obtained using the modified hybrid nuclear model code ALICE-IPPE for intermediate energies. The agreement was found to be generally satisfactory. The data are of importance in proton therapy.

Excitation functions of the reactions (nat)Se(p,x)(75,76,77,82)Br, (76)Se(p,xn)(75,76)Br, (76)Se(p,x)(75)Se and (77)Se(p,xn)(76,77)Br were measured from their respective thresholds up to 40 MeV, with particular emphasis on data for the production of the medically important radionuclides (76)Br and (77)Br. The conventional stacked-foil technique was used. The samples were prepared by a sedimentation process. Irradiations were performed using the compact cyclotron CV 28 and the injector of COSY, both at the Research Centre Julich. In order to validate the data, nuclear model calculations were performed using the code ALICE-IPPE which is based on the preequilibrium-evaporation model. Good agreement was found between the experimental and theoretical data, except in the high-energy region where the calculated data were somewhat higher. All the measured excitation curves were compared with the data available in the literature. From the experimental data the theoretical yields of all the investigated radionuclides were calculated and plotted as a function of proton energy. The calculated yield of (77)Br from the (nat)Se(p,x)(77)Br process over the energy range E(p)=25-->15 is 72.7 MBq/microAh and from the (77)Se(p,n)(77)Br reaction over E(p)=15-->6 MeV it is 86.2 MBq/microAh. The yield of (76)Br from the (76)Se(p,n)(76)Br reaction for E(p)=15-->8 is 360.1 MBq/microAh and from the (77)Se(p,2n)(76)Br reaction for E(p)=28-->18 MeV it is 879.2 MBq/microAh. The radionuclidic impurity levels are discussed.

The excitation function of the 64 Ni( α ,p) 67 Cu reaction was measured from threshold up to 24 MeV in order to investigate the possibility of production of the β − -emitting therapeutic radioisotope 67 Cu ( T 1/2 =61.9 h). Two stacks of thin metallic self-supporting foils of 64 Ni (enrichment 77.8%) prepared by electrolytic deposition were irradiated by α -particle beams. The radioactivity was determined via HPGe detector γ -ray spectrometry. Some 67 Ga activity (which emits the same γ -rays as 67 Cu), formed via the nat Cu( α , x ) 67 Ga process on trace copper impurity in the Ni foils, was also observed. Corrections were done for 67 Ga activity contribution and for the 67 Cu activity escape fraction from the thin Ni-foil. The maximum cross section of the 64 Ni( α ,p) 67 Cu reaction amounts to 34 mb at 22 MeV. The experimental results were compared with theoretical predictions. The integral yield of 67 Cu at 24 MeV α -particle energy, calculated from the excitation function, amounts to 544 KBq/μAh (48.5 MBq/μA at saturation). It is thus a low-yield reaction.

For production of the medically interesting β +-emitter 55Co (T 1/2=17.6 h) via the 54Fe(d,n)-reaction, 91.6% enriched 54Fe2O3, mixed with Al powder, was pressed to a pellet which could be irradiated with 14 MeV deuterons at 4µA in a water-cooled target system. A separation method was developed which led to >99.9% pure 55Co and allowed a recovery of the enriched target material. For a target thickness of E d=12.6 → 5 MeV, the experimental thick target yield of 55Co after chemical separation amounted to about 13 MBq/µA·h, which is about 60% of the theoretical value. In a 3 h irradiation at 4µA, the batch yield of 55Co achieved was 160 MBq (4.3 mCi). An 8 h irradiation could lead to a batch yield of about 400 MBq. The 54Fe(d,n) reaction leads to the highest purity 55Co but it is essential that the isotopic enrichment of the target is not less than 90%. In addition to the production work, cross sections were measured for the 54Fe(d,t) 53Fe and 54Fe(d,α)52mMn reactions using the standard stacked-foil technique and high-resolution γ-ray spectrometry. The cross section ratio for the isomeric pair 52m,gMn is discussed in terms of the spins of the two states involved and the increasing projectile energy.

Optimisation experiments on the production of the positron emitting radionuclides 124I(T(1/2) = 4.18d) and (120g)I (T(1/2) = 1.35 h) were carried out. The TeO(2)-target technology and dry distillation method of radioiodine separation were used. The removal of radioiodine was studied as a function of time and the loss of TeO(2) from the target as a function of oven temperature and time of distillation. A distillation time of 15 min at 750 degrees C was found to be ideal. Using a very pure source and comparing the intensities of the annihilation and X-ray radiation, a value of 22.0 +/- 0.5% for the beta(+) branching in 124I was obtained. Production of 124I was done using 200 mg/cm(2) targets of 99.8% enriched 124TeO(2) on Pt-backing, 16 MeV proton beam intensities of 10 microA, and irradiation times of about 8 h. The average yield of 124I at EOB was 470 MBq(12.7 mCi). At the time of application (about 70 h after EOB) the radionuclidic impurity 123I (T(1/2) = 13.2 h) was 98% as iodide. The amount of inactive Te found in radioiodine was

The cross section for the nat Mo(n, x ) 94 Nb reaction was measured in the energy range from 14.5 to 20.3 MeV using both conventional γ -rayspectrometry and the ultra low-level γ -ray spectrometry (ULGS) facility in the underground laboratory HADES. The exceptionally long half-life of the activation product 94 Nb of 20300 years required a long irradiation, a large sample and a special irradiation geometry, to allow a simultaneous determination of the three data points. This measurement presents the first data above 14 MeV. The data are well described by model calculations with the STAPRE-H code that include the 94 Mo(n, p) 94 Nb and 95 Mo(n, np) 94 Nb reactions.

Summary The radioisotope 90Nb decays with a positron branching of 53% and a relatively low β+-energy of E mean = 0.66 MeV and E max = 1.5 MeV. Its half-life of 14.6 h makes it especially promising for quantitative investigation of biological processes with slow distribution kinetics using positron emission tomography. To optimise its production, the excitation functions of 90Zr(p, xn)-processes were studied over the proton energy range of 7.5 to 19 MeV via the stacked-foil technique using both natZr and 99.22% enriched 90ZrO2 as targets. Thick target yields of 90Nb were calculated from the measured excitation functions and were verified experimentally. The optimum energy range for the production of 90Nb via the 90Zr(p, n)-process was found to be E p = 17 → 7 MeV, with a yield of 600 MBq 90Nb/µA h. The yield and radionuclidic purity of 90Nb over the energy range of E p = 17.6 → 8.1 MeV were determined experimentally using natZr. At 4 h after EOB the yield of 90Nb was found to be 290 MBq/µA h and its radionuclidic purity ≥ 95%.

An improved aluminium target system for production of elemental fluorine via the 18 O(p,n) 18 F reaction using a two-step irradiation protocol is described. In the first step highly enriched gaseous oxygen-18 is irradiated with protons to form fluorine-18 which gets deposited on the inner target surface. In the second step, after cryogenic recovery of oxygen-18 target gas, a mixture of elemental ‘cold’ fluorine and krypton is introduced and a short proton irradiation is done, whereby an isotopic exchange between the gaseous fluorine and the deposited radiofluorine occurs. The second step leads to the recovery of the radiofluorine as [ 18 F]fluorine. Optimisation studies were performed regarding the yield and specific radioactivity of [ 18 F]fluorine. Furthermore, some irradiation parameters relevant to the recovery step were investigated. It was found that a 15 to 20 min irradiation with a beam current of 20 μA is sufficient for the isotopic exchange between the fluorine-carrier and the 18 F-radioactivity deposited on the inner wall of the target. The distribution of the 18 F-radioactivity deposited on the inner target surface is inhomogeneous, probably due to convection effects. Extensive radioanalytical techniques were applied to characterise the reactivity of [ 18 F]fluorine and to identify undesired nonreactive 18 F-compounds, mainly [ 18 F]tetrafluoromethane and [ 18 F]nitrogentrifluoride. The [ 18 F]fluorine produced in the system used has the distinction of having a negligible contamination from those inert 18 F-compounds. This is a combined effect of the use of highest purity gases and a welded target construction, which avoids any contact of the gases with organic material during irradiations. The target has proved to be very reliable for production of [ 18 F]fluorine in high yields of up to 34 GBq and specific activities of 350–600 GBq/mmol, both at 30 min after end of activation bombardment.

Batch electrodeposition based on very dilute (0.14 M) hexavalent chromium electrolyte (2 mL) was optimized in order to produce thin isotopically enriched (e.g., 50 Cr) hard chromium layers on gold backings for use as targets in charged particle irradiations at accelerators. Deposition parameters were systematically investigated. The enriched chromium layers achieve a thickness of about 6 μm after 10 min of electrolysis. The chromium contents of both the deposit and the electrolyte were determined via UV-photometric Cr VI analysis in acid media. A pH range between I and 4 gives an absorption plateau for the two peaks at 257 and 348 nm of acid chromate, thus allowing a precise chromium determination without an exact pH adjustment. Gravimetrically determined deposition yields, especially for long deposition times, were found to differ significantly from the photometrically determined yields. The kinetics of development of the disturbing Cr II content in the electrolyte was investigated using high performance liquid chromatography-based ion-chromatography. The trivalent species was found to accumulate, reaching an absolute maximum of about 10% after 15 min. A chemical pathway is described to produce and to reprocess the hexavalent electrolyte.