v. zagrebaev for pac meeting, 16 june 2001
DESCRIPTION
Possibility for the production and study of heavy neutron-rich nuclei formed in multi-nucleon transfer reactions proposal for a new project at FLNR. V. Zagrebaev for PAC meeting, 16 June 2001. Unexplored area of heavy neutron rich nuclei. fusion. fission. fragmentation. - PowerPoint PPT PresentationTRANSCRIPT
Possibility for the production and study Possibility for the production and study of heavy neutron-rich nuclei of heavy neutron-rich nuclei
formed in multi-nucleon transfer reactionsformed in multi-nucleon transfer reactions
proposal for a new project at FLNRproposal for a new project at FLNR
V. Zagrebaev for PAC meeting, 16 June 2001
Unexplored area of heavy neutron rich nucleiUnexplored area of heavy neutron rich nuclei
fusion
fission
fragmentation
r-process and heavy neutron rich nucleir-process and heavy neutron rich nuclei
(1) difficult to synthesize(2) difficult to separate
Transfermium elementsTransfermium elements
(1) no more alpha-decays !(2) problem of Z identification
Multi-nucleon transfer reactionsMulti-nucleon transfer reactions as a method for synthesis of heavy neutron rich nucleias a method for synthesis of heavy neutron rich nuclei
andand
Stop in gas with subsequent resonance laser ionizationStop in gas with subsequent resonance laser ionizationas a method for extracting required reaction products (with a given Z value) as a method for extracting required reaction products (with a given Z value)
Production on NEW heavy nuclei in the region of N=126Production on NEW heavy nuclei in the region of N=126
“blank spot”
Production on new heavy nuclei in the Production on new heavy nuclei in the Xe + PbXe + Pb collisions collisions
Simulation of typical experiment in the laboratory frameSimulation of typical experiment in the laboratory frame
Test experiment demonstrated good agreement Test experiment demonstrated good agreement with our expectationswith our expectations
Schematic view of the setup for resonance laser ionization Schematic view of the setup for resonance laser ionization of nuclear reaction products stopped in gasof nuclear reaction products stopped in gas
The setup consists of the following elements (units)The setup consists of the following elements (units)
- front end system including: gas cell, system for extraction of the cooled ion beam, electrostatic system for final formation and acceleration of the ion beam (750 k$)
- laser system (900 k$)
- mass-separator (300 k$)
- system for delivery and cleaning of the buffer gas inside the gas cell,- vacuum system,- high voltage and radio frequency units,- diagnostic and control systems for the ion beam.
Required beams of accelerated ionsRequired beams of accelerated ions(the ion beams available at FLNR are well satisfied our requirements)(the ion beams available at FLNR are well satisfied our requirements)
Ions: 16,18О, 20,22Ne, …48Ca, 54Cr, …,86Kr, 136Xe, 238U (i.e., quite different depending on the problem to be solved).
Beam energies: 4,5 – 9 MeV/nucleon (slightly above the Coulomb barrier)
Beam intensity: not restricted (up to 1013 pps).
Beam spot at the target: 3–10 mm in diameter (not very important).
Beam emittance: 20 mm mrad.
Targets: different, including actinides Th, U, Pu, Am, Cm.
At target thickness 0.3 mg/cm2, ion beam of 0.1 pAand efficiency of the facility of 10% we will detect 1 event per secondat cross section of 1 microbarn
Similar setups at other laboratoriesSimilar setups at other laboratories(Jyväskylä: JYFL and ISOLDE)
Similar setups at other laboratoriesSimilar setups at other laboratories(Louvain-la-Neuve Radioactive Beam FacilityLouvain-la-Neuve Radioactive Beam Facility)
CYCLONE 30CYCLONE 110
CYCLONE 44
LISOL
Laser System
LASER ION SOURCE
Cyclotron beam
Gas CellSPIG
Extraction electrode
Gas from purifier
Front end of the LISOL mass separator
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Excimer lasers
Dye lasers
SHGs
Reference cell
Towards LIS, 15 m
4/20
Max. Rep. Rate – 200 Hz
Laser System
Similar setups at other laboratoriesSimilar setups at other laboratoriesJapan, Tokai, KEK, RNB group of MiyatakeJapan, Tokai, KEK, RNB group of Miyatake(setup for 136Xe + 208Pb experiment)
A-, Z-separation
People already involved into discussion of the projectPeople already involved into discussion of the project
Leuven: M. Huyse, Yu. Kudryavtsev, P. Van Duppen
Jyväskylä : Juha Äystö, Iain Moore, Heikki Penttilä
GSI: Michael Block, Thomas Kühl
Mainz: Klaus Wendt
Manchester: Jonathan Billowes, Paul Campbell
FLNR: V. Zagrebaev, S. Zemlyanoi, E. Kozulin and others
Laser systemLaser system
type output power, (average) main & harmonics:(2nd ), {3rd & 4th}, Wt
pulse frequency, Hz
pulse length, ns
wave length, ns
Dye laser 3, (0.3) 104 10-30 213 - 850
Ti:Sapphire 2, (0.2), {0.04} 104 30-50 210 - 860
Eximer laser
30 400 10-20 308
CVL 30-50 103-104 10-30 510.6 & 578.2
Nd:YAG (80-100) 104 10-50 532
Production cost of the laser system with three-step resonance ionization Production cost of the laser system with three-step resonance ionization (combined with the corresponding optic scheme) is about(combined with the corresponding optic scheme) is about 900 k$. 900 k$.
Gas cell and Ion-guide systemGas cell and Ion-guide system
General requirements to the ion-guide systems look as follows: • pressure in gas cell: 100–500 mbar depending on energy of reaction products and required velocity of their extraction;• working gas is He or Ar (the latter looks preferably because its stopping capacity and effectiveness of neutralization are higher);• gas purity not lower than 99,9999%;• cell volume is about 100–200 sm3;• vacuum in intermediate camera not worse than10-2 mbar;• vacuum in the entrance into the mass separator is 10-6 mbar; Some specific requirements, stipulated by the use of the resonance laser ionization, should be also taken into account:
• gas cell should be two-volume to separate the area of thermalisation and neutralization from the area of resonance laser ionization;• extraction of ions from the cell and driving them into the mass separator have to be provided by the sextopole (quadrupole) radio-frequency system which allows one to increase the effectiveness of the setup and to perform ionization of atoms in the gas jet outside the cell; • the input-output setup must be supplied by the system of optical windows and by the system of explicit positioning (0.3 mm) of the gas cell, guide mirrors and prisms. Production cost of the gas cell and ion output systems is about Production cost of the gas cell and ion output systems is about 750 k$.750 k$.
Mass separatorMass separator
All extracted ions have charge state +1 because only neutral atoms are ionized to this state by the lasers while all “non-resonant” ions are removed by electric field before reaching the area of interaction with laser radiation. In this case the extracted particles can be easily separated by masses in dipole magnet. For low-energy (30–60 keV) beams of +1 charged ions no specific requirements are needed for the dipole magnet. It could be a standard magnet separator similar to ISOLDE II, for example: • turning angle 40о–90о,• turning radius of about 1–1.5 m, • focal length of about 1 m,• rigidity of about 0.5 Т/m. Mass resolution is the only critical parameter which should be not less than 1500 (4000 is theoretically feasible). Camera of the separator must have an optical input if collinear laser ionization is used with the sextupole ion-guide (SPIG). Production cost of such mass separator is about Production cost of such mass separator is about 300 k$.300 k$.