CYCLOTRONS 2010 - List of Keywords (pick-up)

Paper	Title	Other Keywords	Page
MOPCP057	A Compact Solution for DDS-Generator, Turn-on and Protections in RF Accelerator Systems	controls, cyclotron, radio-frequency, resonance	159
	A.C. Caruso, F. Consoli, A. Spartà INFN/LNS, Catania, Italy A. Longhitano ALTEK, San Gregorio (CATANIA), Italy
	A single compact rack that includes a Direct Digital Synthesizer generator, a turn-on and protection system provides the smart solution in RF accelerator systems. It synthesizes a high stable RF signal up to 120 MHz, turns the power on into the RF cavities through a step-ramp modulator, protects the RF system against mismatching, sparks and multipactoring. A preliminary prototype has been designed, assembled and tested on the RF system of the k-800 superconducting cyclotron at Infn-Lns. This solution is part of the new computer-based RF control system. The hardware, software, and first test results will be shown in this paper.

MOPCP065	Closed Loop RF Tuning for Superconducitng Cyclotron at VECC	controls, cyclotron, impedance, coupling	180
	A. Mandal, R.K. Bhandari, S.P. Pal, U. Panda, S. Saha, S. Seth, S.S. Som DAE/VECC, Calcutta, India
	The RF system of Superconducting cyclotron has been operational within 9 - 27 MHz frequency. It has three tunable half-wave coaxial cavities as main resonators and three tunable RF amplifier cavities. A PC-based system takes care of stepper motor driven coarse tuning of cavities with positional accuracy ~20 μm and hydraulically driven three couplers and three trimmers. The couplers, in open loop, match the cavity impedance to 50 Ω in order to feed power from RF amplifier. Trimmers operate in closed loop for fine tuning the cavity, if detuned thermally at high RF power. The control logic has been simulated and finally implemented with Programmable Logic Controller (PLC). Precision control of trimmer (~20 μm) is essential to achieve the accelerating (Dee) voltage stability better than 100 ppm and also minimizing the RF power to maintain it. Phase difference between Dee-in and Dee-pick-off signals and the reflected power signals (from cavity) together act in closed loop for fine tuning of the cavity. The close loop PID control determines the final positioning of the trimmer in each power level and achieved the required voltage stability.

MOPCP068	Stable Operation of RF Systems for RIBF	controls, cyclotron, monitoring, heavy-ion	186
	K. Suda, M. Fujimaki, N. Fukunishi, M. Hemmi, O. Kamigaito, M. Kase, R. Koyama, K. Kumagai, N. Sakamoto, T. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan
	At RIKEN RI-Beam Factory (RIBF), heavy ion beams are accelerated up to 345 MeV/u by using the RIKEN heavy ion linac (RILAC) and four ring cyclotrons. In order to provide high intensity beams up to 1puA, all the RF systems must be stable enough for a long term (a few weeks), within ±0.1% in voltages and ±0.1 degrees in phases. For a stable operation of RIBF, we have started to monitor for the RF voltages and phases for all the RF systems, and beam intensity and phases using lock-in amplifiers. We have investigated a degree of stability of the RF systems. Then, we have performed several improvements. The Automatic Gain Control units for RILAC were replaced for a better stability. It was found that the stability of RF systems was considerably affected by the fluctuation of reference signals. The fluctuation was mainly caused by the temperature dependence of power dividers used for a reference signal distribution. Therefore, we have changed the distribution method. The reference signal is first amplified to 40 dBm and divided by directional couplers, and they are delivered to low level circuits. The present degree of stability of the RF systems will be presented.

MOPCP087	Beamloss Monitoring and Control for High Intensity Beams at the AGOR-Facility	beam-losses, cyclotron, injection, controls	227
	M.A. Hevinga, S. Brandenburg, T.W. Nijboer, J. Vorenholt KVI, Groningen, The Netherlands
	Funding: This work is supported by the European Union through EURONS, contract 506065 and the "Stichting voor Fundamenteel Onderzoek der Materie" (FOM). The experiments at the AGOR facility require intense heavy ion beams with a beam power up to 500 W. Examples are 6 x 10¹² pps of ²⁰Ne at 23 MeV/A and 10¹² pps ²⁰⁶Pb at 8.5 MeV/A. To prevent damage to components by the beam (power density >100 W/mm³ in unfavorable cases) a modular beam loss monitoring and control system has been developed for the cyclotron and high energy beam lines. The architecture of the system will be described and the considerations for the major design choices discussed. The system uses the CAN-bus for communication and verification of system integrity. The injected beam is chopped at 1 kHz with a variable duty factor up to 90 %. The beam intensity at injection and a number of locations in the high energy beam line is measured by inductive pick-ups. Furthermore localized beam losses on slits and diaphragms are directly measured. When beam loss in any section exceeds the predefined maximum value the duty factor of the beam is automatically reduced. Beam diagnostics are protected by switching off the beam when they are inserted at too high intensity.

WEM2CIO01	High Power RF Systems and Resonators for Sector Cyclotrons	cyclotron, proton, simulation, extraction	332
	L. Stingelin, M. Bopp, M. Broennimann, J. Cherix, H. Fitze, M. Schneider, W. Tron PSI, Villigen, Switzerland
	In the framework of the high intensity upgrade of the PSI proton accelerator facility, it is planned to replace two existing 150 MHz resonators of the injector II cyclotron by two new 50 MHz resonators. The first prototype resonator has been manufactured by SDMS and first vacuum- and LLRF-tests were carried out. Tuners, coupler and pickups were mounted and high power RF tests are in progress at the teststand. A new building for the RF installation has been built and is ready to house the power amplifiers and LLRF-systems.
	Slides WEM2CIO01 [3.497 MB]

WEM2CCO02	Operating Experience with the RF System for Superconducting Ring Cyclotron of RIBF	cyclotron, acceleration, vacuum, cryogenics	338
	N. Sakamoto, M. Fujimaki, A. Goto, O. Kamigaito, M. Kase, R. Koyama, K. Suda, K. Yamada, S. Yokouchi RIKEN Nishina Center, Wako, Japan
	Since December 2006, Superconducting Ring Cyclotron (SRC) has been operational. Up to now, the beams of ²³⁸U, ⁴⁸Ca, pol-d, N, ⁴He have been provided for nuclear physics experiments. The SRC consists of 6 superconducting sector magnets, 4 accelerating cavities and one flattop cavity. Designed value of the acceleration voltage is 2 MV/turn. The gap voltage of 600 kV is excited with 130 kW rf power in the accelerating cavity. The cavities have been installed at four valley regions of 6 sector magnets and are exposed to a strong stray field of superconducting magnets. The strength of the magnetic field is as large as a few kilogauss. It is found that the condition of multipactor depends drastically on the strength of the stray field. How to treat the multipactor is one of the most important issues for stable operation of the SRC. This paper will discuss on our efforts to settle the problem concerning the cavities. By improving the vacuum, cooling, surface treatment and so on, we finally succeeded to minimize the break time due to the rf break down of the SRC cavities during experiments.
	Slides WEM2CCO02 [9.291 MB]

WEM2CCO05	Beam Diagnostics for RIBF in RIKEN	cyclotron, ion, monitoring, emittance	351
	T. Watanabe, M. Fujimaki, N. Fukunishi, O. Kamigaito, M. Kase, M. Komiyama, R. Koyama, H. Watanabe RIKEN Nishina Center, Wako, Japan
	In the present work, many varieties of beam diagnostics have been played a tremendous role for the RIBF (RI Beam Factory) in RIKEN. During beam user's experiments, it is essential to keep the beam transmission efficiency as high as possible, because the production of RI beams requires an intense primary beam, and the activation of the beam transport chambers induced by beam loss should be avoided. This presentation will include the overview of the Faraday cups, the transverse beam profile monitors, radial probes and phase probes to tune the accelerators and the beam transport line. To realize the stable operation of the accelerator complex, the nondestructive monitoring system of RF fields and beam-phase by using lock-in amplifies are used. Plastic scintillation monitors have been fabricated to evaluate the energy and longitudinal profiles of heavy-ion beams. Furthermore, a highly sensitive beam current (position) monitor with a high Tc (Critical Temperature) SQUID (Superconducting QUantum Interference Device) monitor, has been developed. We will report the present status of the facility, the details of the beam diagnostics and the results of the beam measurement.
	Slides WEM2CCO05 [6.855 MB]

Paper

Title

Other Keywords

Page

MOPCP057

A Compact Solution for DDS-Generator, Turn-on and Protections in RF Accelerator Systems

controls, cyclotron, radio-frequency, resonance

159

A.C. Caruso, F. Consoli, A. Spartà
INFN/LNS, Catania, Italy
A. Longhitano
ALTEK, San Gregorio (CATANIA), Italy

A single compact rack that includes a Direct Digital Synthesizer generator, a turn-on and protection system provides the smart solution in RF accelerator systems. It synthesizes a high stable RF signal up to 120 MHz, turns the power on into the RF cavities through a step-ramp modulator, protects the RF system against mismatching, sparks and multipactoring. A preliminary prototype has been designed, assembled and tested on the RF system of the k-800 superconducting cyclotron at Infn-Lns. This solution is part of the new computer-based RF control system. The hardware, software, and first test results will be shown in this paper.

MOPCP065

Closed Loop RF Tuning for Superconducitng Cyclotron at VECC

controls, cyclotron, impedance, coupling

180

A. Mandal, R.K. Bhandari, S.P. Pal, U. Panda, S. Saha, S. Seth, S.S. Som
DAE/VECC, Calcutta, India

The RF system of Superconducting cyclotron has been operational within 9 - 27 MHz frequency. It has three tunable half-wave coaxial cavities as main resonators and three tunable RF amplifier cavities. A PC-based system takes care of stepper motor driven coarse tuning of cavities with positional accuracy ~20 μm and hydraulically driven three couplers and three trimmers. The couplers, in open loop, match the cavity impedance to 50 Ω in order to feed power from RF amplifier. Trimmers operate in closed loop for fine tuning the cavity, if detuned thermally at high RF power. The control logic has been simulated and finally implemented with Programmable Logic Controller (PLC). Precision control of trimmer (~20 μm) is essential to achieve the accelerating (Dee) voltage stability better than 100 ppm and also minimizing the RF power to maintain it. Phase difference between Dee-in and Dee-pick-off signals and the reflected power signals (from cavity) together act in closed loop for fine tuning of the cavity. The close loop PID control determines the final positioning of the trimmer in each power level and achieved the required voltage stability.

MOPCP068

Stable Operation of RF Systems for RIBF

controls, cyclotron, monitoring, heavy-ion

186

K. Suda, M. Fujimaki, N. Fukunishi, M. Hemmi, O. Kamigaito, M. Kase, R. Koyama, K. Kumagai, N. Sakamoto, T. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan

At RIKEN RI-Beam Factory (RIBF), heavy ion beams are accelerated up to 345 MeV/u by using the RIKEN heavy ion linac (RILAC) and four ring cyclotrons. In order to provide high intensity beams up to 1puA, all the RF systems must be stable enough for a long term (a few weeks), within ±0.1% in voltages and ±0.1 degrees in phases. For a stable operation of RIBF, we have started to monitor for the RF voltages and phases for all the RF systems, and beam intensity and phases using lock-in amplifiers. We have investigated a degree of stability of the RF systems. Then, we have performed several improvements. The Automatic Gain Control units for RILAC were replaced for a better stability. It was found that the stability of RF systems was considerably affected by the fluctuation of reference signals. The fluctuation was mainly caused by the temperature dependence of power dividers used for a reference signal distribution. Therefore, we have changed the distribution method. The reference signal is first amplified to 40 dBm and divided by directional couplers, and they are delivered to low level circuits. The present degree of stability of the RF systems will be presented.

MOPCP087

Beamloss Monitoring and Control for High Intensity Beams at the AGOR-Facility

beam-losses, cyclotron, injection, controls

227

M.A. Hevinga, S. Brandenburg, T.W. Nijboer, J. Vorenholt
KVI, Groningen, The Netherlands

Funding: This work is supported by the European Union through EURONS, contract 506065 and the "Stichting voor Fundamenteel Onderzoek der Materie" (FOM).
The experiments at the AGOR facility require intense heavy ion beams with a beam power up to 500 W. Examples are 6 x 10¹² pps of ²⁰Ne at 23 MeV/A and 10¹² pps ²⁰⁶Pb at 8.5 MeV/A. To prevent damage to components by the beam (power density >100 W/mm³ in unfavorable cases) a modular beam loss monitoring and control system has been developed for the cyclotron and high energy beam lines. The architecture of the system will be described and the considerations for the major design choices discussed. The system uses the CAN-bus for communication and verification of system integrity. The injected beam is chopped at 1 kHz with a variable duty factor up to 90 %. The beam intensity at injection and a number of locations in the high energy beam line is measured by inductive pick-ups. Furthermore localized beam losses on slits and diaphragms are directly measured. When beam loss in any section exceeds the predefined maximum value the duty factor of the beam is automatically reduced. Beam diagnostics are protected by switching off the beam when they are inserted at too high intensity.

WEM2CIO01

High Power RF Systems and Resonators for Sector Cyclotrons

cyclotron, proton, simulation, extraction

332

L. Stingelin, M. Bopp, M. Broennimann, J. Cherix, H. Fitze, M. Schneider, W. Tron
PSI, Villigen, Switzerland

In the framework of the high intensity upgrade of the PSI proton accelerator facility, it is planned to replace two existing 150 MHz resonators of the injector II cyclotron by two new 50 MHz resonators. The first prototype resonator has been manufactured by SDMS and first vacuum- and LLRF-tests were carried out. Tuners, coupler and pickups were mounted and high power RF tests are in progress at the teststand. A new building for the RF installation has been built and is ready to house the power amplifiers and LLRF-systems.

Slides WEM2CIO01 [3.497 MB]

WEM2CCO02

Operating Experience with the RF System for Superconducting Ring Cyclotron of RIBF

cyclotron, acceleration, vacuum, cryogenics

338

N. Sakamoto, M. Fujimaki, A. Goto, O. Kamigaito, M. Kase, R. Koyama, K. Suda, K. Yamada, S. Yokouchi
RIKEN Nishina Center, Wako, Japan

Since December 2006, Superconducting Ring Cyclotron (SRC) has been operational. Up to now, the beams of ²³⁸U, ⁴⁸Ca, pol-d, N, ⁴He have been provided for nuclear physics experiments. The SRC consists of 6 superconducting sector magnets, 4 accelerating cavities and one flattop cavity. Designed value of the acceleration voltage is 2 MV/turn. The gap voltage of 600 kV is excited with 130 kW rf power in the accelerating cavity. The cavities have been installed at four valley regions of 6 sector magnets and are exposed to a strong stray field of superconducting magnets. The strength of the magnetic field is as large as a few kilogauss. It is found that the condition of multipactor depends drastically on the strength of the stray field. How to treat the multipactor is one of the most important issues for stable operation of the SRC. This paper will discuss on our efforts to settle the problem concerning the cavities. By improving the vacuum, cooling, surface treatment and so on, we finally succeeded to minimize the break time due to the rf break down of the SRC cavities during experiments.

Slides WEM2CCO02 [9.291 MB]

WEM2CCO05

Beam Diagnostics for RIBF in RIKEN

cyclotron, ion, monitoring, emittance

351

T. Watanabe, M. Fujimaki, N. Fukunishi, O. Kamigaito, M. Kase, M. Komiyama, R. Koyama, H. Watanabe
RIKEN Nishina Center, Wako, Japan

In the present work, many varieties of beam diagnostics have been played a tremendous role for the RIBF (RI Beam Factory) in RIKEN. During beam user's experiments, it is essential to keep the beam transmission efficiency as high as possible, because the production of RI beams requires an intense primary beam, and the activation of the beam transport chambers induced by beam loss should be avoided. This presentation will include the overview of the Faraday cups, the transverse beam profile monitors, radial probes and phase probes to tune the accelerators and the beam transport line. To realize the stable operation of the accelerator complex, the nondestructive monitoring system of RF fields and beam-phase by using lock-in amplifies are used. Plastic scintillation monitors have been fabricated to evaluate the energy and longitudinal profiles of heavy-ion beams. Furthermore, a highly sensitive beam current (position) monitor with a high Tc (Critical Temperature) SQUID (Superconducting QUantum Interference Device) monitor, has been developed. We will report the present status of the facility, the details of the beam diagnostics and the results of the beam measurement.

Slides WEM2CCO05 [6.855 MB]