PCaPAC2012 - List of Keywords (low-level-rf)

Paper	Title	Other Keywords	Page
THPD16	Fast Digital Feedback Control Systems for Accelerator RF System using FPGA	controls, feedback, LLRF, cavity	172
	P.S. Bagduwal, P.R. Hannurkar, M. Lad, D. Sharma, N. Tiwari RRCAT, Indore (M.P.), India
	Funding: RRCAT Indore Feedback control system plays important role for proper injection and acceleration of beam in particle accelerators by providing the required amplitude and phase stability of RF fields in accelerating structures. Advanced digital technologies allow development of control systems for RF applications. Digital LLRF system offers inherent advantages like flexibility, adaptability, good repeatability and low drift errors compared to analog system. For feedback control algorithm, I/Q control scheme is used. Properly sampling of down converted IF generates accurate feedback signal and eliminates the need of separate detector for amplitude and phase. Controller is implemented in Vertex-4 FPGA with proper control algorithm which offers fast correction with good accuracy and also controls the amplitude and phase in all four quadrants. Single I/Q modulator work as common correctors for both amplitude and phase. LO signal is derived from RF signal itself to achieve synchronization between RF, LO and FPGA clock. Control system has been successfully tested in laboratory with phase and amplitude stability better then ± 1% and ±1°. With minor modification same systems can be used at any frequencies.

THPD20	RF Distribution and Control System for Accelerators of the VEC-RIB Facility	controls, LLRF, cavity, feedback	184
	H.K. Pandey, S. Basak, D.P. Dutta, T.K. Mandi VECC, Kolkata, India A. Kumar, K. P. Ray SAMEER, Kolkata, India
	RIB facility at VECC has several heavy ion linear accelerators like RFQ, two IH-LNACs and one buncher cavity operating at 37.8 MHz and two IH-LINACs with one buncher cavity at 75.6 MHz. Some more RF cavities are being designed at the third harmonic of 37.8 MHz and will be added in the RIB beam line. All the cavities have separate RF power amplifiers with proper amplitude, phase and resonance frequency tuning and control system for efficient and stable operation. The LLRF control system has been operational for the power amplifiers of the existing RF cavities and improved design and development is carried out. The main features of the RF control system are phase and amplitude control of the RF input to the amplifiers and tuning of the RF cavity to the desired resonant frequency with automation using feedback control. It will also have various interlocks for the safety of the load as well as the amplifier. A micro-controller based data acquisition and processing system is being used for control and local/remote operation. The RF distribution system as well as the design details of RF control system will be presented in this paper.
	Poster THPD20 [2.163 MB]

THPD50	FPGA Based Amplitude Control System for Accelerating Cavities	cavity, controls, simulation, pick-up	239
	M.S. Dey, S. Ghosh, A. Mandal, S. Seth, A. Singh, S.S. Som VECC, Kolkata, India
	The FPGA (Field Programmable Gate Array) based digital controller has been implemented for Low level RF voltage control of a 650 MHz cavity. The flexibility of implementing any appropriate control strategy and to have a compact single board solution, FPGA is chosen. The superconducting Cavity is designed to be operated at 650 MHz and 30 kW, CW mode. The voltage from pick-up coil has been fed to the controller after down conversion. The signal is digitized using high speed ADCs. The controller has been tested with different set points and gain parameters from a software connected to the board with serial interface. The FPGA signal processing has been verified according to the required strategy of the reference controller. Some experimental results have been presented for different cavity operational conditions.
	Poster THPD50 [0.613 MB]

Paper

Title

Other Keywords

Page

THPD16

Fast Digital Feedback Control Systems for Accelerator RF System using FPGA

controls, feedback, LLRF, cavity

172

P.S. Bagduwal, P.R. Hannurkar, M. Lad, D. Sharma, N. Tiwari
RRCAT, Indore (M.P.), India

Funding: RRCAT Indore
Feedback control system plays important role for proper injection and acceleration of beam in particle accelerators by providing the required amplitude and phase stability of RF fields in accelerating structures. Advanced digital technologies allow development of control systems for RF applications. Digital LLRF system offers inherent advantages like flexibility, adaptability, good repeatability and low drift errors compared to analog system. For feedback control algorithm, I/Q control scheme is used. Properly sampling of down converted IF generates accurate feedback signal and eliminates the need of separate detector for amplitude and phase. Controller is implemented in Vertex-4 FPGA with proper control algorithm which offers fast correction with good accuracy and also controls the amplitude and phase in all four quadrants. Single I/Q modulator work as common correctors for both amplitude and phase. LO signal is derived from RF signal itself to achieve synchronization between RF, LO and FPGA clock. Control system has been successfully tested in laboratory with phase and amplitude stability better then ± 1% and ±1°. With minor modification same systems can be used at any frequencies.

THPD20

RF Distribution and Control System for Accelerators of the VEC-RIB Facility

controls, LLRF, cavity, feedback

184

H.K. Pandey, S. Basak, D.P. Dutta, T.K. Mandi
VECC, Kolkata, India
A. Kumar, K. P. Ray
SAMEER, Kolkata, India

RIB facility at VECC has several heavy ion linear accelerators like RFQ, two IH-LNACs and one buncher cavity operating at 37.8 MHz and two IH-LINACs with one buncher cavity at 75.6 MHz. Some more RF cavities are being designed at the third harmonic of 37.8 MHz and will be added in the RIB beam line. All the cavities have separate RF power amplifiers with proper amplitude, phase and resonance frequency tuning and control system for efficient and stable operation. The LLRF control system has been operational for the power amplifiers of the existing RF cavities and improved design and development is carried out. The main features of the RF control system are phase and amplitude control of the RF input to the amplifiers and tuning of the RF cavity to the desired resonant frequency with automation using feedback control. It will also have various interlocks for the safety of the load as well as the amplifier. A micro-controller based data acquisition and processing system is being used for control and local/remote operation. The RF distribution system as well as the design details of RF control system will be presented in this paper.

Poster THPD20 [2.163 MB]

THPD50

FPGA Based Amplitude Control System for Accelerating Cavities

cavity, controls, simulation, pick-up

239

M.S. Dey, S. Ghosh, A. Mandal, S. Seth, A. Singh, S.S. Som
VECC, Kolkata, India

The FPGA (Field Programmable Gate Array) based digital controller has been implemented for Low level RF voltage control of a 650 MHz cavity. The flexibility of implementing any appropriate control strategy and to have a compact single board solution, FPGA is chosen. The superconducting Cavity is designed to be operated at 650 MHz and 30 kW, CW mode. The voltage from pick-up coil has been fed to the controller after down conversion. The signal is digitized using high speed ADCs. The controller has been tested with different set points and gain parameters from a software connected to the board with serial interface. The FPGA signal processing has been verified according to the required strategy of the reference controller. Some experimental results have been presented for different cavity operational conditions.

Poster THPD50 [0.613 MB]