Post on 08-Nov-2018
Radioactive Beam Proposal for iThemba LABS
Robert BarkiThemba LABS
Outline of Talk
• Need for a new accelerator
• Ideas for a RIB facility
Rf-system
Sector Magnet
Rf-system
Low Energy In
High Energy Out
Separated-Sector Cyclotron (SSC)
Most Powerful Accelerator in Southern Hemisphere
Separated-Sector Cyclotron FacilitySeparated-Sector Cyclotron Facility
0 10 20 m
beambeamswingerswinger
SSCSSC
SPC1SPC1SPC2 SPC2
Polarized ion sourcePolarized ion source
ECR ion sourceECR ion source
RadioisotopeRadioisotope production production
Neutron therapyNeutron therapy
SpectrometerSpectrometerTarget vaultsTarget vaults
electronicselectronics electronicselectronics
Proton therapyProton therapy
Multi-User Facility
•Proton Therapy: 200 MeV p•Neutron Therapy: 66 MeV p, ~ 40µA•Isotope Production: 66 MeV p, up to 350µA•Nuclear Physics: various beams
◊ Nuclear Physics◊ Nuclear PhysicsNuclear Physics
© Neutron Therapy© Neutron Therapy
© Proton Therapy©© Proton TherapyProton Therapy
© Energy Change©© Energy ChangeEnergy Change
© Isotope Production© Isotope Production
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Proton Therapy
•Paediatric tumours•Tumours close to critical structures•Brain tumours•Gastro-intestinal tumours (rectum, liver, pancreas)•Prostate tumours•Lung tumours•Recurrent tumours
Proton Therapy
Present Schedule Restricted to 2 “Fractions” / week
•Brain tumours
If schedule allowed 5 “Fractions” / week
iThemba LABSRadionuclide Distribution Network
Africa 3
Australia 2
Asia 19
Canada 2
Europe 31
USA 12
Nuclear Physics Research
• Nuclear Structure– Pairing Isomers– Pairing Vibrations– Tetrahedral Shapes– Hyperdeformation– Chirality– Giant Resonances
• Nuclear Reactions– Fusion Barrier Distributions– Incomplete Fusion– Astrophysical reactions– Production of intermediate mass fragments– Reaction Mechanisms
K600 Spectrometer
AFRODITE at iThemba LABSγ-ray spectroscopy
9 Compton Suppressed Clover detectors
8 LEPS detectors
Insufficient beamtime for
HumanResource Development
A Nuclear Future
• Cabinet approved 20-year Integrated Resource Plan
• 9.6 GW Nuclear Power
• ~ 6 ×1600MW Pressurized Water Reactors
• ~ R350 000 000 000
The Future : A New Cyclotron at iThemba LABS
•Isotope Production off SSC (uses 66 MeV p beam) (neutron therapy to be terminated?)•Free SSC for use by Physics and proton therapy only (PT to get 230 MeV machine?)•More than doubles physics beamtime•Two accelerators allow the production of radioactive beams using the ISOL method
C70 GENERAL DESCRIPTION• Diameter < 4m • Weight > 120t• Magnetic Gap: 30mm• Magnetic field: 1.55T• Extraction Radius: 1.2m• 2 exit ports
SPES SPES designdesign
• Particles: H‐ / D‐ / He2+/ HH+
• Variable Energy : 15 MeV 70 MeV
• extraction Systems: Stripper H‐ / D‐
Deflector He2+/ HH+
• Performances:750µA H‐ 70MeV Current upgrade up to 1.5mA35µA He2+ 70MeV
12 weeks
20 weeks
4 weeks
2 weeks
Nuclear Physics: Why Radioactive ion beams ?
Materials Analysis with Radioactive Beams: Hyperfine Structure
Mössbauer Spectroscopy
57Mn implanted into diamonddecays to 57Fe
Spectral components correspondto Fe atoms occupying substitutionaland interstitial sites
K. Bharuth-Ram et al
Electron Emission Channeling
Solid State Physics at ISOLDE
Lattice location of Fe in Diamond
K. Bharuth-Ram et al
59Mn (t1/2 = 4.6s) implanted into Diamond, decays to 59Fe whichβ-decays with t1/2 = 45 days
Electron emission channelingMeasurements indicate that65% of Fe atoms lie within 0.2 ÅFrom a substitutional site
HOW? - Isotope Separation Online (ISOL)
Formation of RIB “group”
•Myself•2 MSc students
•Zipho Ncobo (MCNPX calculations)•Lucky Makhathini (Laser Ionization in collaboration with University of Stellenbosch)
•Dr John Cornell on part-time basis
Floor Plan Version 19
Low-energybeamlines
Mass analyser
Beam cooler
Target / ion-source maintenance Target storage
Robot
RIB productionstations
Location for future injector
Charge breeder
RIB production Performance
OR
OR
MRCyclotron 80.00Facilities for radioisotope productionTwo vaults with four production stations and one experimental station 180.12Beam lines and power supplies 22.93Diagnostic equipment 4.03Vacuum systems 1.95Control system 1.75Radiation detection and interlocking 0.75UPS and power distribution 15.07Water cooling and airconditioning 11.50Buildings and shielding 74.29Site 0.66Contingency 50.00
Total 443.04
Phase I Costs – latest estimates
MRRIB target vaults 45.8Beam Transport(including ECR,cooler,mass separator, vacuum) 85.5Buildings & Infrastructure 20Safety & Control 50Contingency 50
TOTAL 251.3MR
+New Injector? 100
Phase 2 Costs – latest estimates (RIB production only)
Latest cost estimate
Probably can be done for: R450M Phase I (pink)
+R250M Phase II (RIBS) (yellow)+R100M for experiments (?)
Possibly Phase I will become a commercial venture: NECSA/NTP partnership ?
TASKS 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Laser Ion Source Mini Proposal
Construct Mini Laser Ion Source
LIS beam develop./low en. Beams
Total Facility Proposal
Design Process
Approval Process
Upgrade SSC
Construct New Cyclotron
Construct New Isotope Prod. Facility
24/7 SSC Physics Programme
Construction Target/Beam Transport
RIB delivery/physics
iThemba Timeline – Phased Approach
Preliminaries Phase I Phase II
While Phase II is under construction
Increased beam time for stable beam nuclear physics. Talks by:
Andy BufflerRetief NevelingJohn Carter
Which radioactive beams?
•Beams for material sciences•7Be, 22Na, 28Mg, 31Si, 38Cl, 47V, 42K, 43K,• 65Ni, 67Cu, 67Ga, 69Ge, 71As, 73Ga, 110Sn,• 111Ag, 113Ag, 117Cd, 119Sb
•6,8He Paul Papka•Proton Rich ? Nico Orce•Neutron Rich: Fission Target
Proton –rich ⇒different target per beamNeutron-rich ⇒ one 238U target; 100 beams
FISSION URANIUM
Reaching the neutron rich: FISSION URANIUM
SPES target
direct fission at SPES
p-induced fission vs ν-induced fission
HRIHRIBF Calculations
two-step fission vs one-step fission
HRIHRIBF Calculations
best neutron converters
Deuterons on a Carbon converter at GANIL
Can we do better at iThemba?BeO converter (safe, good thermal conductivity)
H Calculations by Deon Steyn
Temp vs time, 2000 rpm wheelTemperature distribution in rotating BeO target 28kW (400µA 70 MeV)
Headache: diffusion & effusion
ionization to 1+ laser-ionization
•Highly Selective•Highly efficient
•~10%•Essential for fission targets
Two-step laser ionization of Sr being demonstrated atStellenbosch University– MSc project of Lucky Makhathini
Charge breeding with 14 GHz ECR source
Limit due to chargebreeding time10ms/Q
Limit due to target diffusion/effusionTime ~ 1.2s
Neutron rich intensities ultimately limited by half lives and diffusion/effusion times
Use IGISOL (gas transport) ?
RIB Production 70 MeV protons 350µA
Sn isotopes
120 122 124 126 128 130 132 134 136 138
Acce
lera
ted
Beam
Inte
nsity
pps
1e+0
1e+1
1e+2
1e+3
1e+4
1e+5
1e+6
1e+7
1e+8
1e+9
1e+10
SPES baseline scaled up 1.4sGas 165 gm U 0.2sSPIRALII (d beam) 5 kg 3.2sBe Conv or SPIRAL II500gm U 3.2sORNL Direct Calc 1.4s
Stable
0.53s
0.25s
1.1s
40s
Accelerated Beam Intensities
0.19s
Neutron-rich post-accelerated yields from 238U(p,f) at 180 µA 70 MeV p (5 x 1.1 cm 6.6g/cm2 UC target at HRIBF).
Refractory elementsIGISOL?
International Comparison ISOL Facilities
FACILITY 132Sn intensity pps(accelerated beam on target)
SPES (Italy) 108
SPIRAL II (France) 109
HRIBF (USA) 108 ?
HIE ISOLDE (CERN) 108
ITHEMBA LABS 108 ?
BRIF (China) 107
KORIA (Korea) 109
Other Beams
Cross – Sections typically more than an order of magnitude higher than for a particular fission fragment.
Implies RIB intensities of up to 1 pnA possible
Separated-Sector Cyclotron FacilitySeparated-Sector Cyclotron Facility
0 10 20 m
beambeamswingerswinger
SSCSSC
SPC1SPC1SPC2 SPC2
Polarized ion sourcePolarized ion source
ECR ion sourceECR ion source
RadioisotopeRadioisotope production production
Neutron therapyNeutron therapy
SpectrometerSpectrometerTarget vaultsTarget vaults
electronicselectronics electronicselectronics
Proton therapyProton therapy
Possible location of RIB test ion-source
RIB ion-source Test Station + β-decay + Materials
Demonstrator with “Unaccelerated” RIBs
The Parallel discussion will divide into Materials and Nuclear groupswith the exception of a discussion around the RIB demonstrator.
Suggested topics for the Nuclear session are:
Light n-rich RIBsAn active TargetCoulex and Proton-rich beamsLarge Acceptance Spectrometer/n-rich beams Desired Beams
Suggested topics for the Materials session are:
Mössbauer SpectroscopyElectron Emission ChannelingDesired Beams
Parallel Discussion
Thank You