Searching the Stabilizing Effects of Neutron Shell Closure via Fusion Evaporation Residue Studies
Searching the “Island of stability” is a topic of
extreme interest in theoretical as well as experimental modern
physics today. This “island of stability” is spanned by superheavy
elements (SHE's) that are produced in the laboratory. SHE's are
believed to exist primarily due to the “magic” stabilizing effects of
nuclear shell structure. SHE synthesis is extremely difficult due to
their very low production cross section, often of the order of pico
barns or less. Stabilizing effects of shell closures at proton number
Z=82 and neutron number N=126 are predicted theoretically. Though
stabilizing effects of Z=82 have been experimentally verified, no
concluding observations have been made with N=126, so far. We
measured and analyzed the total evaporation residue (ER) cross
sections for a number of systems with neutron number around 126 to
explore possible shell closure effects in ER cross sections, in this
 Yu Ts Oganessian and V K Utyonkov “Super Heavy Element Search”
Rep. Prog. Phys. 78, 036301 (2015).
 Rohit Sandal, B. R. Behera, et al., “Probing nuclear dissipation via
evaporation residue excitation functions for the O16,18+Pt198
reactions” Phys. Rev. C 91, 044621 (2015).
 W. J. Swiatecki, The dynamics of nuclear coalescence or Respiration
Physica scripta” 24, 1B (1981) 113
 J. Tōke, R. Bock, et al., Quasi-fission — The mass-drift mode in heavyion
reactions” , Nuclear Phys. A440 , 327 (1985)
 D. Vermeulen, H.-G. Clerc, C.-C. Sahm… “Cross sections for
evaporation residue production near theN=126 shell closure”, Z. Phys. A
318, 157 (1984).
 N Madhavan, S Nath, et al. “Hybrid recoil mass analyzer at IUAC–First
results using gas-filled mode and future plans” Pramana 75, 317 (2010).
 E. Prasad, et al., “Evaporation residue excitation function measurement
for the 16O+194Pt reaction” Phys. Rev. C 84, 064606 (2011).
 Jhilam Sadhukan, Ph D thesis, Homi Bhabha National, Institute
 N. Bohr and J. A. Wheeler, “The mechanism of Nuclear Fission” Phys.
Rev 56, 426 (1936).
 E. Prasad et al., “Fission fragment angular distribution measurements for
16O +194Pt reaction at energies near the Coulomb barrier” Nucl. Phys.
A 882, 62 (2012).
 P. Frobrich and I. I. Gontchar, “Langevin description of fusion, deepinelastic
collisions and heavy-ion-induced fission” Phys. Rep. 292,
 A. V. Ignatyuk et al., Sov. J. Nucl. Phys. 21, 255 (1975).
 H. A. Kramers “Brownian motion in a field of force and the diffusion
model of chemical reactions” 7, 284 (1940).
 R. J. Charity, J.R. Leigh et al., “Heavy-ion induced fusion-fission
systematics and the effect of the compound-nucleus spin distribution on
fission-barrier determination” Nucl. Phys. A 457, 441 (1986).
 R. Rafeie et al., “Strong evidence for quasifission in asymmetric
reactions forming 222Po” Phys. Rev. C77, 024606 (2008)
 R. N. Sagaidak and A. N. Andreyev “Fission barriers for Po nuclei
produced in complete fusion reactions with heavy ions” Phys. Rev. C
79, 054613 (2009).