RF Control Electronics for Linacs Overview of activities at Electronics Division, BARC RF control electronics for: 1.Super-conducting Heavy Ion Linacs BARC-TIFR (150 MHz), IUAC (97 MHz), ANU (150 MHz) keV, 1 mA, 350 MHz, RFQ 3. LEHIPA (20 mA, 20 MeV, CW Proton Linac) 4. BARC-TIFR Injector Linac (Super-conducting)

RF sub-systems BARC-TIFR Super-conducting Linac  RF Electronics for the Super-conducting Resonators a) Resonator Controller : Based on Self-excited-Loop architecture, quadrature power for control. b) RF Power Amplifiers : Solid-state, 150 MHz, 150W.  RF Electronics for the Normal-Conducting Resonators a) Dynamic Phase Reference Generation: Built around a phase detector resonator to correct for drifts in the tandem accelerator, provides stable Phase References to all the RF systems of the linac. b) Resonator Controller: Based on Generator Driven Resonator architecture, A-Q control strategy.

Resonator Directional Couplers Limiter Loop Phase Shifter Phase Detector Gain 0 90 Gain Control Element 0 0 Power Amplifier Phase Ref. Amplitude Ref. Field Amplitude Detector Phase Error Amplifiers Amplitude Error Amplifiers Quiescent Power RF Control of super-conducting Resonators: SEL WITH AMPLITUDE & PHASE LOCK + - Ref. Phase Shifter Input Gain Output Gain

Resonator Controller

Instrumentation Racks for One Local Control Station at TIFR

Electronics for the Normal Conducting Resonators RF Control Electronics for - Low Energy Bunchers (F/16 and F/8) and Sweeper and Corrector (F/32) Amplitude and phase jitters are well below 0.1 % and 0.1 degree Can be used for resonators of different frequencies by change of non- critical components Ease of parameter setting of amplitude and phase Large dynamic range for amplitude control

Off-shoots RF control electronics for: IUAC, New Delhi- –97 MHz thin walled bulk niobium Quarter wave resonators ANU, Canberra –150 MHz Split-loop resonators and Quarter wave resonators

RF Control for 400 keV RFQ Single cavity system  Incorporates Amplitude Stabilisation and Frequency Tracking Signal processing in analog domain Complete functionality divided over a number of simple signal processing modules Utilizes extensively the features available in a Signal Generator

New Technology: –Development in stages: 1.Simplified Version 2.Prototype of the final System Simplified version of the final system –Has only one input and one output channel –Incorporates the main feedback algorithm of amplitude and phase control VHDL code targeting a high speed, high density FPGA is complete System working Digital Low Level RF for 20 Mev Linac

single channel system

Functionalities: High speed High Density FPGA Fast ADCs – 14 bits, 4 nos. Fast DACs – 14 bits, 2 nos Slow DACs – Dual, 10 bits, 3 nos. Clock Generation – PLL synthesizer Memory – 1 MB, 6 nos. cPCI Interface Can serve other applications as well ! Digital processing Card: Four Channel system

DLLRF board in Compact PCI chassis

Testing at TIFR – free running Digital SEL Turn-on transientTurn-off transient Operating quality factor: 5x10 5, Low Field Operation Very smooth operation Oscillations initiate from the noise in the circuit

Experimental Set-up at TIFR

Testing at TIFR – Digital SEL under Locks I Q Resonator Pick-up

BPM of the SPIRAL2 LINAC GANIL (Grand Accelerateur National d’Ions Lourds) in Caen, France  BPM VME Board development (25 nos.)  MVME5500, VxWorks6.8, Spiral2 EPICS IOC, EDM GUI

Software Capabilities Operating System Linux QNX6.2 VxWorks6 uc OS-II Board Support Package QNX & VxWorks for home PPC VME Board using Tundra Universe 2 Language Java, C++, C J2ME Packages Rational Rose, EPICS LabView Citect Scada SQL Server, Oracle Embedded LPC2378, 8051, MSP430

BARC-TIFR Linac - Beam Hall Layout

linac control and information system-salient features 1. Distributed Control System with identical nodes, 2. Easy to expand in terms of number of nodes, 3.LINUX as the operating system for each of the nodes, 4. WEB based user Interface for access from any OS platform, 5. Usage of Java for the software (except device drivers) provides for easy portability, 6. CAMAC as front-end for which in-house expertise is available, 7. Diagnostics support in the system (i.e. detection of CAMAC crate failure)

FOTIA CONTROL ROOM, BARC

IIFC Proposals : BPM BPM under development for Our own accelerator programs Development for Ganil, France SO INLINE WITH OUR PROGRAM

IIFC Proposals: RF interlock System This is interesting More details required, especially regarding sensors Hardware and Software can be easily tested with simulators. But sensors design, fabrication, testing issues have to be sorted out.

IIFC Additional Interest :Low Level RF Control Years of Experience in LLRF development For several Indian Linacs and Australian University Linac Tested Digital implementation of LLRF at TIFR successfully.