# Presentation: 143773

## PROTON LINAC FOR INDIAN SNS

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

## CENTRE FOR ADVANCED TECHNOLOGY, INDORE

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

## 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)

## 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 R&D
- 100 kW power initially
- Injector is 100 MeV proton linac

## Accelerator Driven Sub-critical Systems

## ADSS MOTIVATION

## CONCEPTUAL ADSS FACILITY

## ISNS Layout

## ISNS Parameters

## 
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 

- 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**

## ION SOURCE

## 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

## 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

## PROTOTYPE RFQ

**PROTOTYPE RFQ**

## RFQ Design Parameters

## 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.

## 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

## Drift Tube Linachttp://www.sns.gov/projectinfo/operations/training/lectures/DTL_101.pdf

## DT and Tank details for Tank-1 and Tank-2 

## DT and Quadrupole details for Tanks-3 to 7

## Beam Transmission through DTL

## Beam Phase Space at End of DTL

## 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

## 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