T. K. Nayak

Reaction filters. Charged-particle multiplicity and linear momentum transfer

Abstract The relation between charged-particle multiplicity and linear momentum transfer to heavy reaction residues has been investigated with a 4π charged-particle detector for the reactions 36Ar+238U at E A =35 MeV and 14N+238U at E A =50 MeV . The multiplicity of charged particles at backward angles (θ > 35°) incrreases linear momentum transfer while the multiplicity of charged particles in the forward direction is almost independent of the linear momentum transfer.

A position sensitive high resolution hodoscope for particle unstable intermediate mass fragments

Abstract A position sensitive high resolution hodoscope was developed to detect particle unstable intermediate mass fragments and to resolve the individual excited states of these nuclei. The hodoscope consists of 13 telescopes, four of these telescopes were designed to isotopically resolve fragments with 3 ≦ Z ≦ 10 and the other nine to resolve hydrogen and helium isotopes. In order to optimize the excitation energy resolution of the hodoscope, each telescope contains an x − y position sensitive gas proportional counter. A position resolution better than 0.5 mm is obtained for 5.8 MeV α-particles. This position sensitivity also allows compensation for the thickness nonuniformity of the nonplanar silicon detectors incorporated in the nine light particle telescopes. For proton decay channels of the particle unstable nucleus 14 N ∗ produced in 14 N induced reactions on nat Ag at E A = 35 MeV , the hodoscope provides an excitati energy resolution of about 60 keV (FWHM).

Excited state populations for equilibrium and preequilibrium emission

Abstract Populations of excited 5 Li and 6 Li fragments have been measured for the 3 He + Ag reaction at 200 MeV. At forward angles, fragments emitted via preequilibrium mechanisms display population probabilities that are consistent with emission temperatures of about 4 MeV, comparable to other measurements of preequilibrium processes. In contrasts, fragments emitted to backward angles display much smaller population probabilities consistent with emission temperatures of about 1 MeV. Such low temperatures are consistent with residue excitation energies predicted by molecular dynamics calculations.