Excitation Function for ¹⁷⁸W Production in the ¹⁸¹Ta(p,4n)¹⁷⁸W Reaction over Proton Energy Range 28.8-71.8 MeV

Abstract

178 Ta (T\¡2 = 9.3 min) is of a certain interest to nuclear medicine. It can be produced from a generator following the reaction 181 Ta(p,4n) 178 W 178 Ta. The excitation function for this reaction was measured over the proton energy range of 28.8 -71.8 MeV. Natural Ta in metallic form was used as target material. The cross sections were measured using a conventional stacked foil technique. Our measurements indicated that the maximum cross section of the excitation function is (495 ± 74) mb at 40 MeV. The error in the absolute cross section data was estimated to be ±15%. The results are compared with previous experimental data and theoretical calculations based on the Hybrid Model of nuclear reactions using the well developed computer code Overlaid Alice.With a natural thick tantalum target and 65 MeV proton beam, yields of 178 W are of the order of (1.3 ±0.20) mCi/μΑΙι.

Recommended Nuclear Data for the Production of Selected Therapeutic Radionuclides

“…Because the yield is increasing with energy at a nearly constant rate throughout the energy range considered, and because no tungsten radioisotopes with long half lives exist to reduce the radioisotopic purity of 178 W, irradiations with higher incident energy deuterons are favored. Proton induced reactions on targets of nat Ta are described by six reported measurements [34][35][36][37][38][39]. Measurements describe an excitation very similar in magnitude and energy to the deuteron induced route described above, shown in Figure 5(a).…”

“…The excitation function's single maximum occurs between 35 and 40 MeV, and the width of the principle peak from the 181 Ta(p,4n) 178 W reaction is approximately 15 MeV FWHM. The data from Zaytseva et al [35] and Titarenko et al [39] are deselected for their obvious energy shifts and as outliers from other data, and no other data are modified. Using the selected 39 data points, a 12 parameter Padé fit achieves a χ 2 =1.89.…”

Activation cross sections of α-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: Production of 178W/178mTa generator

“…181 Ta(p,4n) 178 W route Five experimental cross section data sets were found in the literature (see Fig. 20), reported by (Birattari et al, 1971), (Zaitseva et al, 1994), (Michel et al, 2001) (1 energy point), (Uddin et al, 2004) and (Titarenko et al, 2011) (2 energy points). The data of the high energy irradiations by Zaitseva and Titerenko show an upward energy shift near the maximum, probably due to the energy uncertainty at the end of a long stack.…”