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| TUP77 | Status of RF Control System for ISAC II Superconducting Cavities | feedback, linac, resonance, alignment | 450 | ||||
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The rf control system for ISAC II superconducting cavities is a hybrid analogue/digital system using self-excited feedback loop. It has undergone more than a year of testing and improvements have been made to every aspect of the system, including power up sequencing, phase detection, loop regulation, data acquisition as well as communication with EPICS. With a loaded Q of 100,000, amplitude regulation bandwidth of 20 Hz, phase regulation bandwidth of 5 Hz have been achieved.
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| THP42 | NLC Hybrid Solid State Induction Modulator | klystron, induction, pulsed-power, vacuum | 697 | ||||
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The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed power modulator to drive the X-band klystrons. The original NLC envisions a solid state induction modulator design to drive up to 8 klystrons to 500 kV for 3 μs at 120 PPS with one modulator delivering greater than 1,000 MW pulse, at 500 kW average. A change in RF compression techniques resulted in only two klystrons needed pulsing per modulator at a reduced pulse width of 1.6 μsec or approximately 250 MW of the pulsed power and 80 kW of average powers. A prototype Design for Manufacturability (DFM) 8-pack modulator was under construction at the time of the change, so a redirection of modulator design was in order. To utilities the equipment which had already be fabricated, a hybrid modulator was designed and constructed using the DFM induction modulator parts and a conventional pulse transformer. The construction and performance of this hybrid two klystron Induction modulator will be discussed. In addition the next generation DFM induction modulator utilizing a ten turn secondary and fractional turn primary transformer well be presented.
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| THP44 | The Design and Performance of the Spallation Neutron Source Low-Level RF Control System | linac, feedback, klystron, coupling | 703 | ||||
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The Spallation Neutron Source linear accelerator low-level RF control system has been developed within a collaboration of Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. Three distinct generations of the system, described in a previous publication [1], have been used to support beam commissioning at Oak Ridge. The third generation system went into production in early 2004, with installation in the coupled-cavity and superconducting linacs to span the remainder of the year. The final design of this system will be presented along with results of performance measurements.
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[1] M. Champion, et al, "The Spallation Neutron Source Accelerator Low Level RF Control System", Proceedings of the PAC2003 Conference, Portland, Oregon. |
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| THP50 | The CEBAF RF Separator System Upgrade | power-supply, resonance, cathode, ion | 721 | ||||
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The CEBAF accelerator uses RF deflecting cavities operating at the third sub-harmonic (499 MHz) of the accelerating frequency (1497 MHz) to “kick” the electron beam to the experimental halls. The cavities operate in a TEM dipole mode incorporating mode enhancing rods to increase the cavity’s transverse shunt impedance. As the accelerators energy has increased from 4 GeV to 6 GeV the RF system, specifically the 1 kW solid state amplifiers, have become problematic, operating in saturation because of the increased beam energy demands. Two years ago we began a study to look into replacement for the RF amplifiers and decided to use a commercial broadcast Inductive Output Tube (IOT) capable of 30 kW. The new RF system uses one IOT amplifier on multiple cavities as opposed to one amplifier per cavity originally. In addition the new RF system supports the proposed 12 GeV energy upgrade to CEBAF. Currently we are halfway through the upgrade with two IOTs in operation and two more to be installed. This paper reports on the new RF system and the IOT performance.
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| THP83 | Measurements of High Order Modes in High Phase Advance Damped Detuned Accelerating Structure for NLC | dipole, linear-collider, collider, coupling | 791 | ||||
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The RF Technology Development group at Fermilab is working together with the NLC and JLC groups at SLAC and KEK on developing technology for room temperature X-band accelerating structures for a future linear collider. We have built several series of structures for high gradient tests. We have also built 150° phase advance per cell, 60 cm long, damped and detuned structures (HDDS or FXC series). Some of these structures will be used for the 8-pack test at SLAC by the end of 2004, as part of the JLC/NLC effort to demonstrate the readiness of room temperature RF technology for a linear collider. HDSS structures are very close to the final design for the linear collider, and it was very interesting to study the properties of high order modes in the structures produced by semi-industrial methods. In this study advanced RF technique and methods developed at Fermilab for structure low power testing and tuning have been used. The results of these measurements are presented in this paper.
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| FR201 | Accelerator Control and Global Networks - State of the Art | feedback, linear-collider, collider, linac | 847 | ||||
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As accelerators increase in size and complexity, demands upon their control systems increase correspondingly. Machine complexity is reflected in complexity of control system hardware and software and careful configuration management is essential. Model-based procedures and fast feedback based upon even faster beam instrumentation are often required. Managing machine protection systems with tens of thousands of inputs is another significant challenge. Increased use of commodity hardware and software introduces new issues of security and control. Large new facilities will increasingly be built by national (e.g. SNS) or international (e.g. a linear collider) collaborations. Building an integrated control system for an accelerator whose development is geographically widespread presents particular problems, not all of them technical. Recent discussions of a “Global Accelerator Network” include the possibility of multiple remote control rooms and no more night shifts. Based upon current experience, observable trends and rampant speculation, this paper looks at the issues and solutions-–-some real, some probable, and some pie-in-the-sky.
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*Spallation Neutron Source, ORNL and LANL |
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Transparencies
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