| Paper | Title | Other Keywords | Page |
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| MOP022 | Tuning of CLIC Accelerating Structure Prototypes at CERN | cavity, coupling, target | 97 |
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An RF measurement system has been set up at CERN for use in the X-band accelerating structure development program of the CLIC study. Using the system, S-parameters are measured and the field distribution is obtained automatically by using a bead-pull technique. The corrections for tuning the structure are calculated from the result. Integrated software guides cell-by-cell tuning to obtain the correct phase advance and minimum reflection at the operation frequency. The detailed configuration of the system, as well as the semi-automatic tuning procedure, is presented along with a few examples of measurement and tuning of CLIC accelerating structure prototypes. |
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| MOP048 | Experimental Study of the Surface Resistance of the 141 Mhz Quarter-Wave Resonator at Triumf | cavity, ISAC, vacuum, TRIUMF | 166 |
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The upgrade (Phase II) of the ISAC-II superconducting linac has been completed this spring and has been commissioned. Two spare 141 MHz Quarter-Wave Resonators made of bulk Niobium are available at TRIUMF to lead more specific studies on surface resistance. This opportunity has also been taken to optimize the surface treatment to improve the accelerating field gradient at the operating power level. The aim of the study presented here is to link together several surface treatments (etching depth, 120C baking) and test conditions (Q-disease, 4.2 K and 2K tests) and sequence them in an appropriate order to understand more deeply their dependencies. |
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| MOP108 | Planned Machine Protection System for the Facility for Rare Isotope Beams at Michigan State University | beam-losses, controls, linac, diagnostics | 313 |
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The Facility for Rare Isotope Beams (FRIB) at Michigan State University will utilize a 400 kW, heavy-ion linear accelerator to produce rare isotopes in support of a rich program of fundamental research. In the event of operating failures, it is extremely important to shut off the beam in a prompt manner to control the beam losses that may damage the accelerator components such as superconducting cavities. FRIB has adapted the residual beam loss activation limit at 30 cm to be equivalent to 1W/m of operating beam losses. We are designing FRIB MPS to be flexible but redundant in safety to accommodate both commissioning and operations. It is also dependent upon the operational mode of the accelerator and the beam dump in use. The operational mode is distributed via a finite state machine to all critical devices that have multiple hardware checkpoints and comparators. It is important to note that FRIB is a cw machine and MPS status is continuously being monitored by 'device mode change' and real time data link. In this paper, we present FRIB Machine Protection architecture, plans and implementation. |
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| TUP100 | Measuring the Longitudinal Bunch Profile at CTF3 | pick-up, single-bunch, controls, linac | 647 |
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The CLIC Test Facility 3 (CTF3) is being built and commissioned by an international collaboration in order to test the feasibility of the proposed Compact Linear Collider (CLIC) two-beam acceleration scheme. The monitoring and control of the bunch length throughout the CTF3 complex is important since this affects the efficiency and the stability of the RF power production process. Bunch length diagnostics therefore form an essential component of the beam instrumentation at CTF3. This paper presents and compares longitudinal profile measurements based on transverse RF deflectors, Streak camera and non-destructive microwave spectrometry techniques. |
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| THP064 | Design of the Second-Generation ILC Marx Modulator | controls, klystron, diagnostics, status | 899 |
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The SLAC National Accelerator Laboratory is leading an effort to design a prototype Marx modulator to meet the ILC klystron modulator specifications; a 120 kV (± 0.5%), 140A, 1.6 ms pulse at a 5 Hz prf. A first generation prototype, the P1 Marx, has been developed and is undergoing life testing*. The design of a second-generation Marx, P2, has been completed and most sub-systems have been tested**. The P2 advances the Marx topology demonstrated by the P1; eliminating single-point failures, incorporating advanced diagnostics/prognostics, and optimizing engineering margins to improve system availability. The P2 consists of 32 cells, which are individually regulated at an output of up to 4kV. This is in contrast to the P1 Marx which is collectively regulated by a series "Vernier" Marx. The 30 of 32 cell redundancy allows for up to two cell failures without degrading the modulator output. Failed cells can be quickly replaced and remotely-serviced. This paper presents the design of the P2 Marx. Specific topics discussed include the control architecture, mechanical layout, and power electronics design. Experimental results of both a single and array of cells are presented. * C. Burkhart, et al., "ILC Marx modulator development status," LINAC, 2008. |