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BHABHA ATOMIC RESEARCH CENTRE

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Beam Technology Development Group
Accelerator and Pulse Power Division

Development of Electron Beam Accelerators 

500 Kev, 10 KW DC Accelerator

300Mev, 300kW, DC Accelerator

10Mev, 10kW, RF Linac

Indigenisation of RF Components for Linacs

Electron Beam Centre

Electron Beam Accelerators

Development of technology and its translation into the setting up of Electron Beam Accelerators are entrusted with APPD. Depending upon the applications, beams of different power and energy are required. Curing of adhesives and paint coatings, radiation induced polymerization and increased cross linking to improve the thermal and mechanical properties of materials, sterilization of medical products, improved color and acceptability of gems and stones, food preservation etc are some of the newly emerging applications of EB accelerators.

 
Development of Electron Beam Accelerators

Electron beams have established themselves as potential tools both in basic as well as applied sciences and Industry. Beams with varying power and energy are being extensively employed for radiation processing of materials. Electron beam techniques tremendously improves the quality of the products and gives an everlasting effect. Similarly, the electron beam processing of cables & sheets extends better thermal and mechanical properties. The irradiation of semiconductor devices has brought in a total transformation in the IC and microchip industry. The sterilization of the disposable medical products is another area where electron beams have made a big impact. The usage of electron beams for food preservation have revolutionised the concept of food storage. The art of producing exotic colours in gems and stones and thereby making them value added products in the international market by irradiating them with electron beams has been developed. The field is growing and expanding at a fast pace. 

APPD had chalked out an elaborate indigenous Electron beam technological development programme. Depending upon the product and the type of radiation processing, the requirements of energy and power vary from a few hundred keV to a few MeV and the power from a few hundred watts to a few hundred kilowatts. A single accelerator or one type of accelerator cannot meet such requirements. To cover the diverse areas of applications, it was decided to build 500 keV/10 kW, Cockroft Walton based DC accelerator, 3 MeV /30 kW Dynamitron type DC accelerator and a 10 MeV / 10 kW, RF linac.


500 keV, 10 KW DC Accelerator                    

The work was taken up In the year 1995 and completed by the year 2000, It is a Cockroft Walton based DC accelerator designed to give 20 mA of electron beam at an energy of 500 keV. The accelerator is housed at BRIT complex, Vashi, Navi Mumbai. It is in regular operation at a power level of about 5 kW and energy 450 keV. The Radiation Technology Development Section (RTDS), Food Technology Division (FTD), APPD of BARC, IIT Chennai & Industries like RIL are utilizing this facility for surface application work. It is the only indigenously developed accelerator in the country which is operating at such a high power level. This is the only indigenously developed accelerator in the country which is operating at such a high power level. 



An Inner View of 500 keV Accelerator

500 keV facility along with conveyor mechanism

3MeV, 30kW, DC Accelerator                      

This accelerator is designed to deliver 30 kW of beam at an energy of 3 MeV. The 5 keV beam from the electron gun is accelerated to 3 MeV in the acceleration tube. The beam, after passing through the scan magnet chamber is let out in the air through the scan horn and is used for processing of the materials. The 45 kW, 120 kHz, 300 kV Oscillator, is being designed and built for the first time in the country. The corona guard, RF electrodes and HV dome which will handle such large power, are being developed for the first time. Since these products require a good amount of sophistication and do not fall in the conventional manufacture line, the Indian industry had to be educated about each and every aspect of these accelerators. They had to go through a lot of jigs & fixtures and experimentation to acquire the require degree of confidence. At present almost all its subsystems are in the advanced stage of fabrication.

Schematic of 3 MeV, DC Accelerator

Internal View of the 150 – 0 - 150 kV, 120 kHz RF Oscillator for 3 MeV

High Voltage Dome for 3 MeV Accelerator

10 MVA air core Toroidal Transformer for 3 MeV RF Oscillator

 

                                                                                      10MeV, 10kW, RF Linac.

 It is a coupled cavity linac, capable of giving 10 MeV beam with a power of 10 kW. The 50 keV electron beam from the gun is accelerated to 10 MeV in the linac cavity having a length of about 1 m. After the energy analysis, the beam is passed to the scan horn through the sweep scanner. The cavity is powered by a klystron 

A 3D view of the 10 MeV, 10 kW RF Electron Accelerator

Scan horn for 10 MeV Linac

Electron Gun for 10 MeV Linac

Characterisation of 10 MeV Linac Cavity

based source through a wave guide plumbing line consisting of a circulator, directional coupler, ceramic window etc. The linac technology is the most sophisticated one, primarily, the cavity and the microwave source. The cavity should exhibit highest possible Q and the field uniformity at the operating frequency. The geometrical deviations have to be confined within a few tens of microns. Similarly the microwave source ought to show highest possible stability at the maximum power level. SAMEER Mumbai has taken up the task of making the Microwave source. All the microwave components of this accelerator have to handle very high average power, a task to be attempted for the first time in the country. The linac will exclusively be used for industrial applications. 

The 10 MeV Linac components have been fabricated and installation of the linac is in progress at site. A view of the trial assembly done at Centre for Design & Manufacture (CDM), BARC is shown below.


Trial Assembly of the 10 MeV RF Linac at CDM,BARC

                                                                                   
Indigenisation of RF Components for Linacs

RF Linac technology can be put on sound footing if and only if the indigenously designed and built associated components like circulators, directional couplers, water loads, ceramic windows, power dividers etc are

4 Port Phase Shift Circulator developed BY SAMEER, Mumbai (DAE/BRNS Scheme)

 

 

Characterisation of Dual Directional Coupler built by BARC (DAE/BRNS Scheme)

Klystron built by CEERI Pilani (DAE/BRNS Scheme)

made available. Here DAE-BRNS is playing a commendable role. APPD in collaboration with SAMEER Mumbai, took up the task of developing high power circulator, directional coupler, ceramic window and power divider. All these systems are designed to handle average power of 25 kW at the operating frequency of 2856 MHz. Similarly CEERI Pilani in collaboration with CAT Indore, has developed 5 MW Klystron. Views of some of these indigenously developed Microwave devices are shown above.

                                                                  
Electron Beam Centre (EBC): 

Electron Beam Centre, being established at Kharghar, Navi Mumbai, will house two electron accelerators namely a 3 MeV/30 kW and a 10 MeV/10 kW. A view of the same is shown in the Figure below. The building along with all the utilities is functional. At present the accelerator components are being assembled & tested at EBC.



A view of the Electron Beam Centre (EBC) Building

A view of LCW pumping system and SF6 tanks, installed at EBC

Conveyor Belt for 3 MeV installed at EBC

Installation of power supplies at EBC RF Oscillator room

Plug in Door for 10 MeV Linac installed at EBC

 
Electron Beam Accelarators 
Design & Development of Ion Beam 
Development of High Power Pulsed Electron Accelarators 
Compact Pulse Sources 
Special Programs & Advance Technologies