Transcript Slide 1

BEAM INTENSITIES WITH EURISOL
M. Valentina Ricciardi
GSI, Darmstadt, Germany
LAYOUT
"Blocks of knowledge" to be put together to estimate RIB intensities:
1) Set-up
2) Production cross-sections
3) Production rates
4) Efficiencies
5) Possible combination of ISOL + IN-FLIGHT methods
These "blocks of knowledge" are not uncorrelated.
How to proceed?
1. We go through each block and see what we know
2. Provide this information to the user in a simple, accessible way (www)
SET-UP
Primary beam
Standard option: 1 GeV protons: ● on direct target (100 kW)
● on converter target (4-5 MW)
Additional possibilities (compatible with the baseline driver accelerator):
● 2 GeV 3He
● 250 MeV deuterons
● heavier ions with A/Q = 2 up to 125 MeV/u
Target
Direct target
 Protons interact directly with the target material
Indirect target
 Spallation neutron source (most of the heat load)
 Production target (few-MeV neutrons)
PRODUCTION CROSS SECTIONS
Which nuclear reactions are of interest assuming the above set-up?
Direct-target option
Spallation-evaporation with ≤ 1 GeV protons
Spallation-fission with ≤ 1 GeV protons
Fission with secondary neutrons
Indirect-target option
Fission with few-MeV neutrons
PRODUCTION CROSS SECTIONS
Features of spallation reactions
Experimental data taken at the FRS at GSI
Evaporation
residues
Fission fragments
IMF (intermediatemass fragments)
P. Napolitani
J. Taieb, M. Bernas, V. Ricciardi
 Spallation-evaporation produces nuclides reaching from the projectile to about 10 to 15
elements below (a few of them are neutron-rich, most of them are neutron-deficient)
 Spallation-fission (from Th, U) produces neutron-rich nuclides up to Z=65.
PRODUCTION CROSS SECTIONS
Experimental
data taken at the
FRS at GSI
Energy dependence
B. Fernandez
The region on the chart of the
nuclides covered by evaporation
residues extends with increasing
energy available in the system
T. Enqvist
Useful to:
• Fill gaps in target mass
T. Enqvist
• Enhance the production of IMF
PRODUCTION CROSS SECTIONS
Fission. Model Calculation (ABLA)
K. H. Schmidt, A. Kelić
PRODUCTION CROSS SECTIONS
Spallation. Model Calculation (ABRABLA)
IN-TARGET PRODUCTION (production rates)
Additional things enter into the game:
a. Target thickness, material
b. secondary projectiles (mostly neutrons)
c. decay pattern
Important: target material should be feasible!
U. Köster
IN-TARGET PRODUCTION (production rates)
Residue production in thick-spallation targets
(D. Ridikas)
J.-C. David et al, Internal report DAPNIA-07-59, June 2007
30.8 cm natPb
Experiment: at Dubna, Pohorecki et al, NIMA 2006
660 MeV p
Calculations: MCNPX2.5.0 + CINDER'90
Fission residue:
Evaporation residue:
IN-TARGET PRODUCTION (production rates)
Optimization of in-target yields: Direct targets
Courtesy of S. Chabod
Case 183Hg
Optimum target: Pb
Optimum energy: 1 GeV
Optimum target length:
~18 cm?
(extraction efficiency)
EFFICIENCIES
Specific and precise information on the efficiency, nucleus by nucleus
(CERN/ISOLDE)
On progress
In the meantime, profiting of the valuable database(*) of yields at
ISOLDE, a work of Lukić gives an
Overview on the overall extraction efficiency
(GSI)
(*) H.-J. Kluge, Isolde users guide, CERN, Geneva, 1986, web: http://isolde.cern.ch
EFFICIENCIES
Correlation of ISOL yields with isotope half-life
 Comparison of ISOLDESC yields to in-target
production rates
 Ratio yield/produced →
overall extraction efficiency
for the nuclide
S. Lukić et al.
EFFICIENCIES
Same general behavior found in many cases.
  t 1  
 2
s

t
 1 
1  2 
 t0 
 
S. Lukić et al.
EFFICIENCIES
K.H. Schmidt
EFFICIENCIES
K.H. Schmidt
Can we
extract some
general
tendency from
the measured
data?
...work in
progress
TWO-STEP REACTION: ISOL + IN-FLIGHT
J. Benlliure et al
GSI experiment S294 (November 2006)
What is
cold fragmentation
Participating institutes:
Universidad de Santiago de Compostela, Spain
Centre d’Etudes Nucleaires BordeauxGradignan, France
Warsow University, Poland
GSI Darmstadt, Germany
VINCA-Institute Belgrade, Serbia
Institute of Physics, Bratislava, Slovakia
TWO-STEP REACTION: ISOL + IN-FLIGHT
Two-step schemes: fission + cold fragmentation
Production of medium-mass neutron-rich nuclei
2. Use cold
fragmentation
of 132Sn to
produce
medium-A
neutron-rich
nuclei
1. Produce 132Sn
via fission in
uranium target
TWO-STEP REACTION: ISOL + IN-FLIGHT
Experimental setup at FRS
GSI experiment S294 (November 2006)
S0-S2: 238U(950 A MeV) + Be  132Sn
B/~ 3 10-4
ToF ~ 72 ps
L ~ 18 m
Z2 ~ E
A/A ~ 1.3 10-3
e
Z
A
 B 
m0c
 
S2-S4: 124-132Sn + Be  X
B/~ 3 10-4
ToF ~ 100 ps
L ~ 36 m
A/A ~ 1 10-3
TWO-STEP REACTION: ISOL + IN-FLIGHT
Fragmentation of 132Sn (Preliminary results)
Fragmentation of 132Sn on Be
D. Perez and D. Dragosavac
Preliminary cross sections are available
TWO-STEP REACTION: ISOL + IN-FLIGHT
Energy of the post
accelerator
Charge state can cause
impurity
BEAM-INTANSITY DATA-BASE
Courtesy of Wojtek Gawlikowicz, Univ. Warsaw
http://www-w2k.gsi.de/eurisol-t11
http://www.slcj.uw.edu.pl/~wojtek/eurisol_database.php
CONCLUSIONS
• Consistent description of nuclide production
• Calculations of in-target yields in progress
• Study of the extraction efficiencies in progress
• Feasibility of the two-step reaction scheme experimentally proven
• EURISOL beam-intensities data-base in progress
Beam intensities with EURISOL
EURISOL DS Task 11
Task leader: Karl-Heinz Schmidt, GSI-Darmstadt
Participants and contributors: ISOLDE-CERN, CEA/Saclay, University of
Jyväskylä, University of Warsaw, IoP Bratislava, GSI-Darmstadt, University
Santiago de Compostella, Khlopin Radium Institute, VINČA-INS Belgrade