Radioactive Ion Beam

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Radioactive Ion Beam Project _at_ VECC,
KOLKATA
Siddhartha Dechoudhury
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SHE
Why to study Exotic Nuclei
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184
p-drip line
p-drip line nuclei
Test of Standard Model NZ nuclei Superallowed
b-decay
Atomic Physics, Material science with RI Beams
rp-process
n-drip line
r-process path Origin of elements, Stellar
Nucleosynthesis
New Magic Numbers Shell Quenching
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RIB facility at VECC Kolkata
1.5 keV/u
98 keV/u
29 keV/u
Dedicated beam-line for material science
experiments
Installation in progress
415 keV/u
286 keV/u
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Thick target RD first few targets
Carbon , Al2O3, ZnO, HfO2, BN, LiF, MgO,
CaCl2, ThC2, UC2, ZrO2
Fibrous Target
Composite Thick Target
Al2O3 fiber
RVCF Al2O3
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• Conceptualization of nano particles
• Problem with grain growth due to sintering

dTM 4.2(D.?1/2)1/2
ZnO
ZnO SiO2
Confirmation of zinc silicate phase from X-ray
data
Grain size 4-5 ?m
Grain size gt limit. grain size (10 ?m)
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Integrated Thick-Target Electron Beam Plasma
Ion-Source
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Two-Ion Source Charge Breeder design
calculations
SIMION

• 1 beam Surface ion-source e10 ?.mm.mrad E
  15 keV

• point-to-point beam transport 1 ion-source to
  end of dipole

TRANSPORT

• deceleration injection of 1 beam into ECR
  ion-source

IGUN
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2-IS charge breeder beam-dynamics simulation

• 1 beam from the Surface ion-source injected
  into 6.4 GHz ECR ion-source for further
  ionization to n
• Gradual deceleration of 1 beam ( 20 eV) soft
  landing inside ECR

Plasma chamber
I 1 mA
Axial magnetic field
Tuner
Center of ECR plasma
Decelerator
Decelerated beam
14 mm
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6.4 GHz On-Line ECR ion-source _at_ VECC
6.4 GHz Microwave
Dipole magnet
Solenoid coils
Injection box
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RADIOFREQUENCY QUADRUPOLE (RFQ) first
post-accelerator

• Acceleration of RIB from 1 to 98 keV/u
• Heavy Ion RFQ ? q/A 1/16 f 37.6 MHz
• Extended rod structure ? Vane Length 3120 mm
  Vane Voltage 49.5 kV
• Transmission 83

RFQ development ? stage 1 ? ½ scale model
stage 2 ? 29 keV/u
RFQ stage 3
? 98 keV/u final RFQ
29 keV/u heavy-ion RFQ _at_ VECC
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29 keV/u heavy-ion RFQ (close-up)

Result of Full power tests 29 keV/u RFQ
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Energy measurement of RFQ output beam
Test Beam Ar 4
Beam line RFQ-Q1-Q2-Dipole
Experimental Results
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Dirtha das expt.
Fe Implantation on ZnO
Fe extracted from ECR
using MIVOC technique
Fe irradiated ZnO sample
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Chemically co-doping 2 at. Fe along with 2 at.
Mn in ZnO J. of Phys. D 41(2008) 135006,
M.Chakrabarti et.al
Beam Parameters

• Beam 56Fe
• Ion energy 29 keV/u i.e., 1.6
  MeV 56Fe after RFQ
• Implantation depth 1 mm
• (Bragg peak width of 0.2 mm (TRIM calculation)
• Total number of ZnO 5 1017 (in 1 cm2 area
  of thickness 0.5 mm)
• Available current 900 nA for 56Fe6
  5 1011 56Fe / sec
• NOTE
• Number of ions required for 2 Fe
  implantation in ZnO 1016

Substantial enhancement in magnetisation in Fe
implanted ZnO
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Result of tests with 98 keV/u RFQ
3.4m RFQ during installation
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RFQ to LINAC BEAM LINE (MEBT)
Re-buncher parameters Frequency 37.6
MHz Max. gap vol. 13.75 kV No. of gaps 4
Drift tubes 140 x 140 sq. mm
50mm dia. hole 48 mm long
Drift tube gaps 9.85 mm
OPTIMISED DESIGN PARAMETERS RFQ-Buncher
distance 2.2 m
Buncher-Linac distance 1.5 m
Buncher Voltage
13.75 kV BEAM PARAMETERS AT INPUT OF LINAC 1
Energy 85.6
keV/u ? ?W
? 7o ??
? 1 RE-BUNCHER CAVITY (?/4 RESONATOR) Drift
tube dimensions 140 mm x
140 mm L48 mm
Beam hole diameter
50 mm Inter drift tube gap
9.85 mm Total length
width of the cavity 232 mm x 232 mm
Height of the short 0.68
m Inner and outer conductors of the TL 60mm
? (O.D) 216mm ? (I.D) Q value
5750 Rp value
173 k?
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Heavy-ion IH LINAC for RIB

• Acceleration of RIBs after RFQ from 98 keV/u to
  415 keV/u
• IH LINAC ? q/A 1/16 f 37.6 MHz E_max
  1.3E_K (10.2 MV/m)
• Transmission 100 Normalised acceptance en
  0.5 p-mm-mrad

LINAC Cavity
D.T. Stem
Drift Tubes
Lower Ridge
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Linac -1 during assembly
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• Status of RIB facility development

• 98 keV/u stable beams available from the facility
  
• beams available Oxygen, Nitrogen, Carbon,
  Argon, Iron,
• 1.5 keV/u (after ECR) 98 keV/u (after RFQ)
• Linac 1 2 presently under installation.
• 280 keV/u beam would be available by July/August
  2008. Linac 3 (415 keV/u) would be ordered soon.
  
• First RI beams planned
• 13N(t1/2 10 mins) graphite
  target
• 19Ne(t1/2 17 sec) ZnO
  target
• Beams December 2008 first proof of principle
  acceleration of RIB

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?- induced fission (photo-fission) GDR peak at
13.5 MeV average photo-fission cross-section
160 mb  
Expected yield of some very neutron-rich exotic
nuclei at target 78Ni 2 x 109 pps
132Sn 2 x 1011 pps 91Kr 1 x 1012 pps
94Kr 3 x 1010 pps
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and e-Linac
TRIUMF
Parameters of e-Linac (nine cell)
50kW
50kW
50kW
50kW
50kW
10kW
13MeV
53MeV
Gun
50kW
50kW
50kW
50kW
50kW
10kW
Injector
Driver
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First horizontal test module proposed to be
jointly developed by VECC and TRIUMF
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Recent publications from RIB project group (in
international journals)

• J. of Phys. D (in press) Experiments (condensed
  matter (CM))
• J. of Phys. C20 (2208) 45217, Experiments (CM)
• J. of Mat. Sciences 43 (2208) 4175, Experiments
  (CM)
• Phys. Lett. A 371 (2007) 482. Experiments (CM)
• Nucl. Instrum. Meth. B261(2007)1018. RIB
  facility status
• Rev Sci Instrum. Vol78 (2007) 043303. RFQ
  results
• J of Phys. Condensed Matter 19, (2007) 236210.
  Experiments
• Ceramics International 34 (2008) 81 Target
• Nucl. Instrum. Meth. VolA560 (2006)182. Linac
  design
• Nucl. Instrum. Meth. VolA562 (2006)41.
  Beam-line
• Nucl. Instrum. Meth. VolA539 (2005)54. Target
• Nucl. Instrum. Meth. VolA547 (2005)270. Charge
  breeder design
• J. of Mat. Sc. 40 (2005) 5265. Experiments (CM)
• Nucl. Instrum. Meth. VolA535 (2004)599. RFQ
  design
• Physica C, Vol416, (2004) 25. Experiments (CM)
• Nanotechnology 15 (2004) 1792. Target
• Nucl. Instrum. Meth. VolA447 (2000)345. Charge
  breeder design
• __________________________________________________
  ____________________________
• Number of Ph. D degree awarded during 2005-07
  Four

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THANK YOU
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238U photo-fission fragments mass distribution
fission yield per electron for 238U as a function
of electron energy