Jishnu Dwivedi – On behalf of RRCAT team

jishnu@rrcat.gov.in

Development of 10 MeV, 6 kW Linacs and

Radiation Processing Facility at Indore

1. Objectives

2. Details of Radiation Processing Facility (ARPF),

3. Beam, accelerator and process requirements,

4. Overall current status

5. Plans to be pursued

These points will be presented in this talk.

Outline

Introduction

1. Develop 10 MeV rugged indigenous accelerators for societal application

2. Develop beam delivery systems for various applications

3. Develop associated systems for bulk radiation processing (process interrupt handling, energy filter,…)

4. Demonstrate technical suitability of the indigenous accelerators for various societal applications

5. Demonstrate economic viability of indigenous accelerator technology for Indian societal applications

Objectives

RRCAT has developed two 10 MeV, 5 kW electron linacs for electron beam radiation

processing. The linacs have been endurance tested for several hundred hours of operation.

RRCAT is developing a Radiation Processing Facility at Indore Fruits & Vegetable Market using

these linacs. Beam trials with the first linac are in process. Second linac is planned to be

installed later this year (2018).

The facility has a product handling system, dosimetry system, and all the necessary

infrastructure for demonstrating radiation processing using the electron linacs.

Several applications of the electron beam will be demonstrated.

Medical

sterilization

Microbial

hygienation

Phytosanitary

irradiation

Mutation

breeding

10 MeV Electron Linac based Radiation Processing Facility at Indore

1. The ability to double break DNA strands in living organisms such as cells, bacteria and insects making them sterile. • Radiotherapy for treatment of cancer,

• Disposable medical product sterilisation and antiseptic packaging

• Live insect elimination in food,

• Disinfection of the spices and herbs without fumigation,

• Quarantine for fruit flies /weevil in fruit,

• Fungus treatment in food – Salmonella, Listeria,

• E-coli elimination in foods.

2. Ability to penetrate with precisely determinable scattering • X-ray imaging for NDT, Cargo scanning, Medical imaging

3. Ability to form free radicals and form new bonds • Cross linking of polymers, curing, breakdown cellulose

• Waste water treatment and Dye elimination

• Flue gas treatment

4. Ability to produce mutation for mutation breeding of crop varieties

Properties of electron beam/x-rays which make them usable

However, an appropriate radiological shielding is required for protection

Targeted Radiation Processing Applications at the Facility

Radioactive source

like Cobalt-60

Electron Accelerator

applications

Imaging Radiotherapy Surface processing < 3 MeV Bulk processing

10 MeV

Food cans Medical sterilization Quarantine - Fresh

fruit Insect

Disinfestation

pulses, dried food

Municipal waste

treatment

microbial

decontamination

Spices, herbs

Delay ripening

1. Beam parameters. • Adjustable beam energy 7 MeV / 9.5 MeV

• Low energy spread

• High beam power (viability begins at ~ 50 kW)

2. Linac requirements • High stability, efficiency, reliability, robust

• Energy filter to eliminate particles higher than regulatory limits

• Low O&M costs and quick recovery after maintenance

3. Process requirements • Ability to handle process interrupt without discarding the product,

• Log the process data and store process data for long time.

• Qualification and routine dosimetry,

• Develop process compatible product packaging.

• Incoming and outgoing product testing and certification.

Important requirements for bulk radiation processing

1. Accelerators is operated within the stipulated limits and with high stability,

reliability and data logging.

2. The “packed” product is loaded onto the conveyor in the product hall and it is

automatically moved to the accelerator vault.

3. The product passes with controlled speed in front of the beam.

4. A “process-interrupt handling system” is used to handle accelerator trips without

discarding the product.

5. Processing of one box typically takes 1 to 5 minutes. The packaging or the box

need not be opened.

6. No radioactivity is involved.

How Radiation Processing is done with Accelerator

Linac-B1

Linac-B Linac-C

Type, Frequency 2π/3, Traveling Wave, 2856 MHz

Beam energy (max.), MeV 10 and 7.5

Beam Pulse Current, mA 200 350 / 475

Energy spread 10% 7% (for 90% particles)

Beam Pulse Duration, s 10 10

Pulse Repetition Rate, Hz 300 300

Average Beam Power, kW 5 10

Current Status Developed In-process (Dec-2018)

Electron linac specifications

18 cell SUPERFISH

simulation - 5 MeV, 3 kW

9.5 / 7 MeV 10 kW

Cavities -

1 – prebuncher

5 – buncher

45 - regular

2D-Electromagnetic

design of Pre-buncher

cavity

Physics Design: 10 / 7.5 MeV Dual Energy 10 kW Electron Linac

Learning: Engineering designs and experiments

Numerous component performance tests and

beam experiments Conceptual and engineering designs

100

150

0 10 20 30 40 50

Ph

ase

ad

van

ce

Cavity number

Phase advance per cell measured using Bead-Pull method

The linac assembly consists of vacuum brazed ultra precision machined cells

Cell inspection dimensional and surface High precision machining

Leak testing Brazed RF coupler

Development of accelerating structure

Control rack Gun PS Klystron Gun Modulator

Linac-B1 with its subsystems under testing at RRCAT

Operating Parameters

Beam Power : 5 kW

Beam Energy : 9 MeV

Beam current : 270 mA

Pulse Width : 10 µs

Endurance test: 30 – 8 hr shifts

Shifted to ARPF after endurance testing at RRCAT

Linac-B1: 8-hour shift operation test

Linac-B1: Endurance test - 90 Hours non-stop operation

Linac-B2

Electron Gun Solenoids

Beam Monitor Electron window and target

Linac-B2 under qualification at RRCAT

• As per regulations, maximum electron energy < 10 MeV (< 7.5 MeV in x-ray).

BPM

Chromatic

magnet

BPM

PSM

BPM

MESUREMENT SLIT FARADAY

CUP SLIT

CT CT

Beam Diagnostics

Typical result of Beam Profile Measurement

Endurance test at 6 kW and short duration test at 9 kW

22 7/7/2018

Date of operation: 20-21, Dec 2017, Uninterruptedly for 32 Hrs.

10 AM Dec 20, 2017

6 PM Dec 20, 2017

2 AM Dec 21, 2017

10 AM Dec 21, 2017

6 AM Dec 20, 2017

Beam ON Time (Hrs.)

Endurance test Linac-B2: Nonstop 32 hrs. operation

Dosimetry

Dosimetry System

Alanine EPR Dosimetry

System

Dose Range:

0.05 to 50 kGy

Radiochromic

film dosimetry

systems

GaFchromic films

Dose range: 0.05-1 kGy

B3 films Dose range:

1 - 80 kGy

Alanine EPR dosimetry system Radiochromic film dosimetry system

Dosimetry Laboratory

Facility Commissioning – Expected 2018

ARPF Layout

Equipment room

Linac-B1 during installation

Electron beam Irradiation

Radiation Field Characterization

Energy measurement using RISO Al

wedge as per ASTM 51649

Surface dose uniformity along scan direction

Beam Parameters

Energy 9 MeV

SSD 20 cm

Conveyor

speed

0.5 m/min.

Scanning

parameters

8.0 A @

400msec.

±3% over the full box height = 43 cm

Do

se U

nif

orm

ity

stri

p

Experimental radiation processing Petri Dishes using 9 MeV e-beam

Volumetric DUR achieved in

sterilization of petri dishes

irradiated with electron

beam

Volumetric Dose Measurement as per AERB/RF-RPF/SG-1 (with LINAC-1)

Mutant breeding experiments done using Electron Beam

Mutation breeding in Groundnut seeds Mutation breeding in Rice

Conclusion

1. The dosimetric measurements indicate suitability of the developed linacs for medical sterilization (with process interrupt handling).

2. Beam trials with Linac-B1 at ARPF: Beam power of 4. 5 kW reached.

3. Linac-B2 will be installed in April-May 2018.

4. Testing of the overall integrated system as radiation processing facility to be conducted in coming months.

5. Approvals of the regulatory bodies to be obtained for radiation processing using Linac-B.

6. Using add-on components beam power and beam delivery systems of the two linacs will be improved.

33

1. Accelerator & Beam Physics Section – Physics design

2. Accelerator Control Systems Division – Control system development

3. Accelerator Magnet Technology Division – Magnetic elements and collinear load development

4. Beam Diagnostics & Coolant Sys Division – Beam diagnostics and precision cooling system

5. Construction & Services Division – Radiological shielding and infrastructure systems

6. Design & Mfg Technology Division – Vacuum brazing and component manufacturing

7. Indus Operations & Alignment Section – Magnet Fiducialization and alignment

8. Industrial Accelerators Division – Facility design, Accel structure, beam experiments, dosimetry, processing

9. Laser Controls & Instrumentation Division – Search, secure & safety system; process interrupt

10. Power Converters Division – Scanning and magnetic supplies, HV measurements

11. Precision Power Supplies Division – Fire alarm and safety system.

12. Pulsed High Power Microwave Division – Electron gun and microwave system

13. Ultra High Vacuum Technology Section – Vacuum system

14. Health Physics Team – Radiation survey and Radiation Safety Duties.

15. RF Systems Division and Accelerator Physics Section for consultation on several technical matters

16. Indian Industries – for a large number of components for iterative developments

Acknowledgement