LINAC2012 - List of Authors (Roy, A.)

Paper

Title

Page

Superconducting Low Beta Niobium Resonator for Heavy Ions

588

P.N. Prakash, K.K. Mistri, A. Roy, J. Sacharias, S.S. Sonti
IUAC, New Delhi, India

For the high current injector at Inter-University Accelerator Centre, a new superconducting niobium resonator optimized for β = 0.05 operating at 97 MHz, has been designed and fabricated. This resonator has the highest frequency in its class among the superconducting structures designed for such low velocity particles. The resonator has been carefully modeled using Microwave Studio code to minimize the peak magnetic field in order to achieve high accelerating gradients in it. Even though the resonance frequency is high, the physical dimensions of the resonator are large enough to allow processing of its superconducting surface effectively. The mechanical design of the resonator has been modeled using ANSYS multiphysics to increase the frequency of the lowest mechanical eigenmode of the central co-axial line, and also reduce liquid helium induced pressure fluctuations in the resonator. Bead pull measurements have been performed on the niobium resonator and they match with the design values very well. Cold tests at 4.2 K will be performed in the next few weeks. This paper will briefly present the design of the low beta resonator and details of the results from the cold tests.

TH1A04

Superconducting Linac and Associated Developments at IUAC Delhi

763

A. Roy
IUAC, New Delhi, India

A superconducting linear accelerator system consisting of a series of independently phase locked niobium quarter wave resonators has been developed as a booster of heavy ion beams available from the existing 15UD Pelletron accelerator. Two superconducting linac booster modules having eight niobium quarter wave resonators (QWRs) each have been installed and are fully operational for regular scheduled experiments. The third module is being added to the system. A new high current injector has been planned to couple to the superconducting linac. For this a high temperature superconducting electron cyclotron resonance ion source (HTS-ECRIS) was designed, fabricated and installed successfully. A radio frequency quadrupole (RFQ) accelerator is being developed for accelerating accelerate ions from the ECR (A/Q ~ 6) to an energy to of about 180 keV/A. The beams will then be accelerated further by drift tube linacs (DTL) to the required velocity to inject them to the existing superconducting linac booster. Prototypes of both these have been tested for power and thermal studies. Details of these developments and associated systems will be presented.

Slides TH1A04 [7.830 MB]

TUPB033

Piezoelectric Actuator Based Phase Locking System for IUAC Linac

549

B.K. Sahu, R. Ahuja, G.K. Chowdhury, R.N. Dutt, S. Ghosh, D. Kanjilal, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, A. Pandey, P. Patra, A. Rai, A. Roy, S.K. Suman
IUAC, New Delhi, India

The linac of IUAC consists of three main accelerating modules with each one housing eight superconducting quarter wave resonators. Currently, the phase locking of the resonator is performed by a combination of fast I-Q based electronic tuner and helium gas flow based mechanical tuner. Microphonics measurement on the resonators found the presence of lower frequency vibrations along with main mechanical mode (~60 Hz) of the resonators. Although main mechanical mode of the resonator is damped by using SS balls, the presence of lower frequency vibrations demand more RF power from the amplifier, as the existing mechanical tuner works in time scale of seconds. A combination of piezoelectric actuator based fast tuner along with stepper motor based coarse tuner operating in the time scale of milliseconds is being developed. This scheme is implemented on a few resonators in last linac cryostat. Initial results show that this mechanism can arrest all low frequency vibrations thereby reducing a substantial load from the electronic tuner and improve the dynamics of the phase locking scheme. The implementation scheme along with test results will be presented in detail.

Paper	Title	Page
TUPB049	Superconducting Low Beta Niobium Resonator for Heavy Ions	588
	P.N. Prakash, K.K. Mistri, A. Roy, J. Sacharias, S.S. Sonti IUAC, New Delhi, India
	For the high current injector at Inter-University Accelerator Centre, a new superconducting niobium resonator optimized for β = 0.05 operating at 97 MHz, has been designed and fabricated. This resonator has the highest frequency in its class among the superconducting structures designed for such low velocity particles. The resonator has been carefully modeled using Microwave Studio code to minimize the peak magnetic field in order to achieve high accelerating gradients in it. Even though the resonance frequency is high, the physical dimensions of the resonator are large enough to allow processing of its superconducting surface effectively. The mechanical design of the resonator has been modeled using ANSYS multiphysics to increase the frequency of the lowest mechanical eigenmode of the central co-axial line, and also reduce liquid helium induced pressure fluctuations in the resonator. Bead pull measurements have been performed on the niobium resonator and they match with the design values very well. Cold tests at 4.2 K will be performed in the next few weeks. This paper will briefly present the design of the low beta resonator and details of the results from the cold tests.

TH1A04	Superconducting Linac and Associated Developments at IUAC Delhi	763
	A. Roy IUAC, New Delhi, India
	A superconducting linear accelerator system consisting of a series of independently phase locked niobium quarter wave resonators has been developed as a booster of heavy ion beams available from the existing 15UD Pelletron accelerator. Two superconducting linac booster modules having eight niobium quarter wave resonators (QWRs) each have been installed and are fully operational for regular scheduled experiments. The third module is being added to the system. A new high current injector has been planned to couple to the superconducting linac. For this a high temperature superconducting electron cyclotron resonance ion source (HTS-ECRIS) was designed, fabricated and installed successfully. A radio frequency quadrupole (RFQ) accelerator is being developed for accelerating accelerate ions from the ECR (A/Q ~ 6) to an energy to of about 180 keV/A. The beams will then be accelerated further by drift tube linacs (DTL) to the required velocity to inject them to the existing superconducting linac booster. Prototypes of both these have been tested for power and thermal studies. Details of these developments and associated systems will be presented.
	Slides TH1A04 [7.830 MB]

TUPB033	Piezoelectric Actuator Based Phase Locking System for IUAC Linac	549
	B.K. Sahu, R. Ahuja, G.K. Chowdhury, R.N. Dutt, S. Ghosh, D. Kanjilal, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, A. Pandey, P. Patra, A. Rai, A. Roy, S.K. Suman IUAC, New Delhi, India
	The linac of IUAC consists of three main accelerating modules with each one housing eight superconducting quarter wave resonators. Currently, the phase locking of the resonator is performed by a combination of fast I-Q based electronic tuner and helium gas flow based mechanical tuner. Microphonics measurement on the resonators found the presence of lower frequency vibrations along with main mechanical mode (~60 Hz) of the resonators. Although main mechanical mode of the resonator is damped by using SS balls, the presence of lower frequency vibrations demand more RF power from the amplifier, as the existing mechanical tuner works in time scale of seconds. A combination of piezoelectric actuator based fast tuner along with stepper motor based coarse tuner operating in the time scale of milliseconds is being developed. This scheme is implemented on a few resonators in last linac cryostat. Initial results show that this mechanism can arrest all low frequency vibrations thereby reducing a substantial load from the electronic tuner and improve the dynamics of the phase locking scheme. The implementation scheme along with test results will be presented in detail.