PROTON LINAC FOR INDIAN SNS

1
PROTON LINAC FOR INDIAN SNS

• Vinod Bharadwaj, SLAC
• (reporting for the Indian SNS Design Team)

2
CENTRE FOR ADVANCED TECHNOLOGY, INDORE

• DAE lab, SLAC size in people, area
• New lab built 1987 for accelerator laser RD
• Presently has 450 MeV electron ring (INDUS-1) for
  synchrotron light RD, accelerators for
  industrial use RD
• In the process of building 2.5 GeV synchrotron
  radiation facility (INDUS-2), to start operations
  in 2004

3
CENTRE FOR ADVANCED TECHNOLOGY, INDORE

• CAT is the lead 50M collaboration with LHC to
  build superconducting correction magnets
• Has a lot of internal expertise in building
  equipment for accelerators
• Indian Government is interested in accelerator
  facilities and international collaborations
  (meeting in Delhi in Nov 2003, where this was
  emphasized in person by the Secretaries of DST
  and DAE)

4
INDIAN INTEREST IN HIGH INTENSITY PROTONS

• Indian Government is interested in protons
• Accelerator Driven Sub-critical Systems
• burning thorium for energy production
• Accelerator Driven Transmutation of Waste
• Indian Spallation Neutron Source
• Part of long range plan
• Basic research ADS RD
• 100 kW power initially
• Injector is 100 MeV proton linac

5
Accelerator Driven Sub-critical Systems
6
ADSS MOTIVATION
7
CONCEPTUAL ADSS FACILITY
8
ISNS Layout
9
ISNS Parameters
10

• Design Specifications of
• 100 MeV H Linac
• Input energy 4.5MeV 
• Output energy 100MeV     
• Beam current 25mA 
• Particles H- 
• Operating mode Pulsed  
• Pulse duration 500?sec 
• Repetition rate 25Hz 

Linac Design dominated by the need to Reduce
beam losses to reduce heating and activation
Injector needs to be capable CW operation for
injection into future SC linac Injector needs
to be upgradeable to higher current for future
ISNS upgrade
11
ION SOURCE
12
Low Energy Beam Transport
Provides transverse phase space matching between
ion-source and RFQ Chops beam for matching into
RFQ buckets Use codes TRACE3D IGUN for
optimization
13
RFQ Design

• Use design code PARMTEQM for particle
  transmission and SUPERFISH for cavity design
• Two designs ..
• 25 mA, lower vane voltage, lower beam losses ,
  better for higher duty factor/CW operations
• 50 mA for pulsed operations, can use higher vane
  voltages for better beam properties
• Plan is to build 25 mA first to get experience
  and then upgrade to 50 mA when needed
• Calculations show 96.3 transmission efficiency

14
PROTOTYPE RFQ
15
RFQ Design Parameters
16
MEBT Design Consideration

• It is very essential to match the beam from
  one accelerating structure to the next one to
  avoid the formation of beam halo and emittance
  blow up and subsequent beam loss. The MEBT
  provides necessary matching between RFQ and the
  following drift tube linac. The matching in three
  phase planes is studied by TRACE3D. The MEBT
  section uses four quadrupoles, two RF gaps and a
  combination of drift spaces for matching in
  transverse and longitudinal planes. The design
  goal was to obtain the mismatch factors below
  0.01 in all the three phase planes.

17
Drift Tube Linac

• Use DTL structure for accelerating from 4.5 MeV
  output of RFQ to 100MeV injection into the SNS
  proton synchrotron, operating at 350 MHz
• Accelerating gradient ramped from 1.8 MV/m to 2.2
  MV/m from tank 1 to tank 2 and then held at 2.2
  MV/m
• Possibility to use S(eparated function) DTL
  structures for the higher (50 MeV) energies.
  Tradeoff between ease of manufacture and beam
  quality being calculated
• 7 tanks, tanks 3-7 the drift tubes have face
  angle for improved shunt impedance
• Drift bore is 1 cm throughout the linac

18
Drift Tube Linachttp//www.sns.gov/projectinfo/op
erations/training/lectures/DTL_101.pdf
19
DT and Tank details for Tank-1 and Tank-2
20
DT and Quadrupole details for Tanks-3 to 7
21
Beam Transmission through DTL
22
Beam Phase Space at End of DTL
23
High power pulsed klystron

• Frequency of operation 350MHz /- 2.5MHz
• Output peak power 1MW or 2MW
• Output RF pulse duration 700 microsecs
• Gain 43dB
• Maximum drive power 200W
• Efficiency 60
• Output waveguide WR 2300
• Focusing Electromagnet

24
CONCLUSION

• India has ambitious plans for high intensity
  proton beams, for SNS ADSS
• A design for a 100 MeV, 25-50 mA H-minus linac
  exists
• SNS project approved in principle and design
  efforts are underway