THOAA —  Beam Instrumentation and Feedback   (08-Sep-11   09:30—10:30)
Chair: K. Wittenburg, DESY, Hamburg, Germany
Paper Title Page
THOAA01 Beam Diagnostics Commissioning at CNAO 2848
 
  • H. Caracciolo, G. Balbinot, G. Bazzano, J. Bosser, M. Caldara, A. Parravicini, M. Pullia, C. Viviani
    CNAO Foundation, Milan, Italy
 
  The National Centre for Oncological Hadrontherapy (CNAO) is the first Italian facility for the treatment of deep located tumors with proton and carbon ion beams using active scanning. The commissioning with proton beams is concluded and CNAO is going to start treating patients with protons; in the meantime the machine commissioning with carbon ions beam is going on. Beam diagnostics instrumentation is fundamental to measure beam properties along the lines from sources to patients. Some significant measurements performed during proton beam commissioning and the performances achieved with the CNAO beam diagnostic systems are presented in this paper.  
slides icon Slides THOAA01 [4.827 MB]  
 
THOAA02 Implementation of an Intensity Feedback-loop for an Ion-therapy Synchrotron 2851
 
  • C. Schömers, E. Feldmeier, Th. Haberer, J. Naumann, R.E. Panse, A. Peters
    HIT, Heidelberg, Germany
 
  The Heidelberg Ion Therapy-Centre (HIT) started treatment of tumour patients in 2009. Its main acceleration stage is a synchrotron, where particles are extracted slowly, in the time frame of some seconds, to support the raster-scanning method. The slow extraction is driven by the transverse "RF-nockout-exciter". So far, this device has a variable but predefined amplitude curve. As the phase-space distribution of particles is not homogeneous and varies slightly from pulse to pulse, intensity-fluctuations of the extracted beam appear. Moreover, changing accelerator-settings requires a time-consuming re-adjustment of the exciter to achieve adequate beam-properties again. To keep the intensity on a predefined level, a feedback loop will be implemented. The actual-value of the intensity is provided by an ionization chamber in front of the patient. The feedback loop controls the amplitude of the Exciter, to adapt the number of extracted particles. Beside a rectangular spill with constant intensity, a dynamic intensity-adaptation during one spill with respect to the particular treatment-plan will be investigated. First tests for flat spill and variable intensity showed promising results.  
slides icon Slides THOAA02 [2.284 MB]  
 
THOAA03 Overview of LHC Beam Loss Measurements 2854
 
  • B. Dehning, A.E. Dabrowski, M. Dabrowski, E. Effinger, J. Emery, E. Fadakis, V. Grishin, E.B. Holzer, S. Jackson, G. Kruk, C. Kurfuerst, A. Marsili, M. Misiowiec, E. Nebot Del Busto, A. Nordt, A. Priebe, C. Roderick, M. Sapinski, C. Zamantzas
    CERN, Geneva, Switzerland
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
 
  The LHC beam loss monitoring system based on ionization chambers is used for machine protection, quench prevention and accelerator optimization. After one full year of operation it can be stated that its main functionality, that of the protection of equipment, has proven to be very robust with no issues observed for hundreds of critical beam loss events and the number of false beam aborts well below expectation. In addition the injection, dump and collimation system make regular use of the published loss measurements for system analysis and optimisation, such as the determination of collimation efficiency in order to identify possible intensity limitations as early as possible. Intentional magnet quenches have been performed to verify both the calibration accuracy of the system and the accuracy of the loss pattern predictions from simulations. Tests have also been performed with fast loss detectors based on single- and polycrystalline CVD diamond, which are capable of providing nanosecond resolution time loss structure. This presentation will cover all of these aspects and give an outlook on future performance.  
slides icon Slides THOAA03 [1.972 MB]