102 research outputs found
GABRIELA : a new detector array for gamma-ray and conversion electron spectroscopy of transfermium elements
With the aid of the Geant4 Monte Carlo simulation package a new detection
system has been designed for the focal plane of the recoil separator VASSILISSA
situated at the Flerov Laboratory of Nuclear Reactions, JINR, Dubna. GABRIELA
(Gamma Alpha Beta Recoil Investigations with the Electromagnetic Analyser
VASSILISSA) has been optimised to detect the arrival of reaction products and
their subsequent radioactive decays involving the emission of alpha- and
beta-particles, fission fragments, gamma- and X-rays, and conversion electrons.
The new detector system is described and the results of the first commissioning
experiments are presented.Comment: 24 pages, Submitted to NIM
On-line separator for -spectroscopic studies at FLNR JINR
International audienceA JINR — IN2P3 collaboration project named “GABRIELA” aimed at the nuclear spectroscopy of transfermium elements using the recoil separator VASSILISSA was launched in 2004 at JINR in Dubna. In the close future the FLNR cyclotron U400M will go through a major upgrade with the goal to deliver heavy ion beams at the energy close to the Coulomb barrier in a new experimental area. Here we report about R&D of the new separator for spectroscopic studies which we plan to install at the beam of the modernized accelerator and which will allow to realize new possibilities of the GABRIELA project
Separator for Heavy ELement Spectroscopy – velocity filter SHELS
International audienceThe SHELS velocity filter originated upon reconstruction of the VASSILISSA electrostatic separator used for investigations of heavy nuclei produced in complete fusion reactions. The goals of this modernization were to increase the transmission of products of asymmetric reactions and to extend the region of reactions to be investigated up to symmetric combinations. The first tests of the set-up were performed with the beams of accelerated 22 Ne, 40 Ar, 48 Ca, and 50 Ti ions
The emission of prompt neutrons from the spontaneous fission of No-252 and Fm-244
The neutron detector with (3)He -filled counters placed in the focal plane of the VASSILISSA separator is used for measuring the average number and determining the multiplicity distribution of prompt neutrons from the spontaneous fission of heavy short-lived isotopes. The test reaction is used for tuning the separator settings and calibrating the detector system with the spontaneous fission of the (252)No . The average neutron number per (252)No spontaneous fission event is as large as . The short-lived heavy isotope (244)Fm , produced in the complete fusion reaction (40)Ar + (206)Pb , is investigated. The average number of neutrons per spontaneous fission of (244)Fm from the experimental data ( is determined for the first time
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