S. Takács

Evaluation of proton induced reactions on 100Mo: New cross sections for production of 99mTc and 99Mo

The use of the 99Mo→99mTc generator in nuclear medicine is well established world wide. The production of the 99Mo (T1/2 = 66 h) parent as a fission product of 235U is largely based on the use of reactor technology. From the early 1990s accelerator based production methods to provide either direct produced 99mTc or the parent 99Mo, were studied and suggested as potential alternatives to the reactor based production of 99Mo. A possible pathway for the charged particle production of 99mTc and 99Mo is irradiation of molybdenum metal with protons via the reaction 100Mo(p,2n)99mTc and 100Mo(p,pn)99Mo, respectively. The earlier published excitation functions show large differences in their maximum that result in large differences in the calculated yields. We therefore decided to study the excitation function for these proton-induced reactions. In this work the newly measured excitation functions as well as an evaluation of earlier measured data and a discussion of the observed disagreements are presented.

New cross-sections and intercomparison of deuteron monitor reactions on Al, Ti, Fe, Ni and Cu

Abstract The 27Al(d,x)22,24Na reactions are frequently used to monitor deuteron beams above 20 MeV. To extend possible monitoring energy region toward lower energies, new monitor reactions are proposed and experimental cross-sections are measured for the processes 27Al(d,x)22,24Na, natTi(d,x)48V, natFe(d,x)56Co, natNi(d,x)61Cu and natCu(d,x)65Zn. The excitation functions were studied using the activation method on stacks of thin metallic foil targets with natural isotopic composition. The data sets of the six processes were cross-checked with each other to provide reliable numerical cross-sections. Detailed literature compilation and critical comparison were made on the available data sets for the studied reactions. Predictions of model calculations were compared with the new experimental data. After establishing selection criteria, consistent data sets were chosen for each of the processes, which were then fitted with a spline or Pade method to provide recommended cross-sections.

New cross-sections and intercomparison of proton monitor reactions on Ti, Ni and Cu

Abstract The excitation functions of proton induced reactions on Ti, Ni and Cu were studied using activation method on stacks made of thin metallic foil targets with natural isotopic composition. Since titanium, nickel and copper are ideal target material with respect to their availability, physical, mechanical and chemical properties the use of the nat Ti(p,x) 48 V, nat Ni(p,x) 57 Ni, nat Cu(p,x) 62 Zn, nat Cu(p,x) 63 Zn and nat Cu(p,x) 65 Zn processes are suitable for monitoring the intensity and/or energy of charged particle beams. These processes are recommended under 40 MeV bombarding proton energy as monitor reaction. The new data sets of these five processes were cross-checked with each other to provide reliable consistent numerical cross-sections. Results were compared to the recommended cross-section values reported recently by the International Atomic Energy Agency [IAEA TECDOC-1211, 2001].

Excitation functions of deuteron induced nuclear reactions on natural zinc up to 50 MeV

Excitation functions were measured for production of 66,67Ga, 62,65,69mZn, 61,64,67Cu and 58Co radioisotopes in deuteron induced reactions on natural Zn up to 50 MeV by activation using stacked foil techniques. Detailed compilations were made of the earlier reported experimental cross-section and integral yield data. They are compared with the new values and theoretical calculations. The use of the measured formation cross-section for production of practically important radioisotopes of gallium and copper is discussed as well as the application of cross-section data of 65Zn in the field of wear monitoring by the thin layer activation method.

Excitation function of the 18O(p,n)18F nuclear reaction from threshold up to 30 MeV

The available experimental data on the most common route for the production of 18F, viz. 18O(p,n)18F reaction, obtained both via neutron spectral studies and activation measurements, were critically reviewed. In some energy regions the cross section database was found to be rather weak or discrepant. In order to fill the gaps and to clear some of the discrepancies, the excitation function was remeasured from threshold up to 30 MeV using different solid and gas targets containing highly enriched 18O. For this purpose a van de Graaff machine (Ep <4 MeV) and several cyclotrons (Ep = 4-30 MeV) were utilized. The new experimental data help to prepare a recommended data set. At Ep = 14 MeV the integral yield of 18F calculated from the new excitation curve is slightly higher than that from the hitherto accepted data set; at Ep > 14 MeV the yields reported here are new.

Remeasurement and compilation of excitation function of proton induced reactions on iron for activation techniques

Abstract Excitation functions of proton induced reactions on nat Fe(p, xn) 56 Co have been remeasured in the energy region up to 18 MeV using stacked foil technique and standard high resolution gamma-ray spectrometry at the Debrecen MGC-20E cyclotron. Compilation of the available data measured between 1959 and 1993 has been made. The corresponding excitation functions have been reviewed, critical comparison of all the available data was done to obtain the most accurate data set. The feasibility of the evaluated data set was checked by reproducing experimental calibration curves for TLA by calculation.

Excitation function for the natTi(p,x)48V nuclear process: Evaluation and new measurements for practical applications

Abstract In order to supply accurate databases for different practical purposes such as proton beam energy monitoring, 48 V radioisotope production, nuclear analytical applications and nuclear wear measurements, we have evaluated the cross-sections of the nat Ti ( p , x ) 48 V nuclear process up to 50 MeV. Since the preliminary overview of the status of the cross-section data showed that there are discrepancies between the literature results, we performed detailed cross-section measurements up to 18 MeV. The selected literature data and our new experimental values were also compared with the predictions of different model calculations. Recommended cross-sections and thick target yield databases up to 50 MeV were developed for practical applications.

Validation and upgrading of the recommended cross section data of charged particle reactions used for production of PET radioisotopes

A validation test and upgrading of the recommended cross section database for production of PET radioisotopes in charged particle induced reactions, published by the IAEA in 2001, was performed. Experimental microscopic cross section data published earlier or measured recently and not yet included in the evaluation work of IAEA were collected and added to the primary database in order to improve the quality of the recommended data. The newly compiled experimental data supported the previous recommended data in most cases, but in a few cases this influenced the decision made earlier and resulted in new selected cross section data sets. A spline fitting method was applied to the selected data sets and updated recommended data were produced in these cases. The integral thick target yields deduced from the new recommended cross sections were critically compared with experimental yield data available in the literature.

Experimental study of excitation functions for some reactions induced by deuterons (10–50 Mev) on natural Fe and Ti

Stacks containing high purity natural Fe and Ti foils were irradiated in deuteron beams with incident energies of 30 and 50 MeV. Reactions on Al foils were used for monitoring beam energy and intensity. The excitation functions up to 50 MeV for natTi(d, x)44m,46,47,48Sc, natFe(d, x)55,57Co, 52,54Mn, 51Cr are presented and compared with the scarce literature values. No sharp peaks enabling clear identification of contributing reactions on the different naturally occurring isotopes are present. Only for the reactions 56Fe(d, n)57Co (Q=−2.1 MeV), 56Fe(d, α or 2p2n)54Mn (Q values respectively 5.7 and −22.6 MeV), 48Ti(d, α or 2p2n)46Sc (Q values 4 and −24.3 MeV) and 48Ti(d, 2pn)47Sc (Q=−13.7 MeV) on the major natural isotopes of Fe and Ti the cross sections reach values higher than 50 mb in the energy region studied.

Investigation of the production of the therapeutic radioisotope 114mIn through proton and deuteron induced nuclear reactions on cadmium

Summary For production of the therapeutic radionuclide 114mIn, proton and deuteron induced nuclear reactions were investigated using the stacked-foil technique on enriched 114Cd and natCd targets up to Ep = 36 MeV and Ed = 21 MeV. The experimental cross sections of the 114Cd(p, γ)115mIn, 114Cd(p, n)114mIn, 114Cd(p, 2n)113mIn, 114Cd(p, 4n)111m,gIn, 114Cd(p, αn)110mAg, 114Cd(p, α)111m,gAg, 114Cd(d, n)115mIn, 114Cd(d, 2n)114mIn, 114Cd(d, 3n)113mIn, 114Cd(d, p)115gCd, 114Cd(d, α) 112Ag, 114Cd(p, αn)111m,gAg, natCd(p, x)114mIn and natCd(d, x)114mIn reactions are reported. Thick target yields are derived and different routes for production of 114mIn are compared.