Mass and charge release by the evaporation of particles from compound nuclei around mass 60

Abstract

Reaction product cross sections have been measured for reactions of 4He projectile with 54'5617e, 58Ni and 59C0 targets in the bombarding energy range 14-27 MeV. The cross-section-weighted average charge A Z and mass AA removed from the compound system were deduced and compared with results reported for heavy-ion induced reactions. Variation ofA A with E* N is independent of the initial angular momentum of compound nucleus in the A = 60 mass region in contrary to the rare-earth region. This would suggest a strong angular momentum removal from the compound nucleus by evaporation of particles for A ,~ 60 nuclei. The average evaporated charge AZ depends on both the CN excitation energy E~N and the compound nucleus N and Z numbers. The AA and AZ dependence on excitation energy and the projectile-target combination can be understood in terms of the statistical model calculations.

Nuclear model analysis of excitation functions of proton and deuteron induced reactions on 64 Zn and 3 He- and α-particle induced reactions on 59 Co leading to the formation of copper-61: Comparison of major production routes

“…11. The data of McGowan et al (1964) exist near the threshold region and appear consistent with the measurements by Stelson and McGowan (1964) Skulski et al (1992) and Szelecsényi et al (2002) show fairly good concurrence within their uncertainties. The results of the nuclear model calculations by the EMPIRE and TALYS codes are also shown in Fig.…”

“…The cross section values by Homma and Murakami (1976) are discrepant near the reaction threshold and are lower in the region of the maximum of the reaction. The measured data points of Michel and Brinkmann (1980) are in good agreement with other measurements, including Gadioli et al (1984); Levkovskij (1991); Skulski et al (1992); Singh et al (1993) and Szelecsényi et al (2002). Two data points by Skulski et al (1992) at 14.5 MeV and 26 MeV appear to be very inconsistent and were therefore discarded.…”

“…Hermanne at al. (1999) reported cross Cohen et al, 1954;Barrandon et al, 1975;Levkovskij, 1991;Hermanne et al, 1999;Szelecsényi et al, 2005;Uddin et al, 2007 64 Zn(d,αn) 61 Cu À 1.38 Baron and Cohen, 1963;Williams and Irvine, 1963;Bissem et al, 1980;Bonardi et al, 2003;Tárkányi et al, 2004;Daraban et al, 2008 59 Co( 3 He,n) 61 Cu 6.61 Homma and Murakami, 1976;Michel and Galas, 1983;Jastrzebski, et al, 1986;Nagame et al, 1988;Szelecsényi et al, 2004;Fenyvesi et al, 2004;Pichard et al, 2011 59 Co(α,2n) 61 Cu À 13.9 Sterns, 1962;Budzanowski et al, 1967;Zhukova et al, 1972;Homma and Murakami, 1976;Michel and Brinkmann, 1980;Gadioli et al, 1984;Jastrzebski, et al, 1986;Levkovskij, 1991;Skulski et al, 1992;Singh et al, 1993;Szelecsényi et al, 2002;Ansari et al, 2004 sections only above 32 MeV on nat Zn target, so those data were not considered in the evaluation. Szelecsényi et al (2005) performed extensive cross section measurements up to 100 MeV; however, in Fig.…”

“…59 Co(α,2n) 61 Cu A number of groups measured the cross sections for production of 61 Cu through this reaction (Sterns, 1962;Budzanowski et al, 1967;Zhukova et al, 1972;Homma and Murakami, 1976;Michel and Brinkmann, 1980;Gadioli et al, 1984;Jastrzebski, et al, 1986;Levkovskij, 1991;Skulski et al, 1992;Singh et al, 1993;Szelecsényi et al, 2002;Ansari et al, 2004; see Table 1). All the experimental data are shown in Fig.…”

Interaction of stopped antiprotons with copper

“…Assuming now that, on the average, the evaporation of 1 mass unit in this mass region decreases the excitation energy of the thermalized reaction product by 9.7 MeV [33], the above (b, A ) value gives an upper limit of the average excitation energy (E'), of about 120 MeV. In order to get a value rather than a limit, the number of nucleons emitted in the fast reaction phase has to be estimated.…”