Author: Brunner, O.
Paper Title Page
WEPPC029 Design and Development of an Octopus Thermometric System for the 704 MHz Single-cell SPL Cavity at CERN 2266
 
  • K.C. Liao, L. Arnaudon, O. Brunner, E. Ciapala, D.C. Glenat, W. Weingarten
    CERN, Geneva, Switzerland
 
  The octopus thermometric system is designed for the 704 MHz superconducting proton linac (SPL) cavity to detect hot spots and X-rays caused by normal conducting defects and the impact of emission electrons. This system features an octopus body and tentacle structure for good contact with the cavity and easy assembly, a multiplexing circuit with integrated microprocessor for efficient readout and a high density temperature sensor arrangement in order to complete a high resolution temperature and X-ray map. The first prototype is being manufactured and investigations are undergoing for further development.  
poster icon Poster WEPPC029 [1.715 MB]  
 
WEPPC030 Second Sound Measurement Using SMD Resistors to Simulate Quench Locations on the 704 MHz Single-cell Cavity at CERN 2269
 
  • K.C. Liao, O. Brunner, E. Ciapala, T. Junginger, W. Weingarten
    CERN, Geneva, Switzerland
 
  Oscillating superleak transducers (OSTs) containing a flexible porous membrane are widely used to detect the so-called second sound temperature wave when a quench event occurs in a superconducting RF cavity. In principle, from the measured speed of this wave and the travel time between the quench event and several OSTs, the location of the quench sites can be derived by triangulation. Second sound behavior has been simulated though different surface mount (SMD) resistors setups on a Superconducting Proton Linac (SPL) test cavity, to help understand the underlying physics and improve quench localisation. Experiments are described that have been conducted to search for explanation of heat transfer mechanism during cavity quench that causes contradictory triangulation results.  
poster icon Poster WEPPC030 [1.473 MB]  
 
THPPD056 Performance of the Crowbar of the LHC High Power RF System 3641
 
  • G. Ravida, O. Brunner, D. Valuch
    CERN, Geneva, Switzerland
 
  During operation, the LHC high power RF equipment such as klystrons, circulators, waveguides and couplers have to be protected from damage caused by electromagnetic discharges. Once ignited, these arcs grow over the full height of the waveguide and travel towards the RF source. The burning plasma can cause serious damage to the metal surfaces or ferrite materials. The "crowbar" protection system consists of an arc current detector coupled with a fast high voltage switch in order to rapidly discharge the main high voltage components such as cables and capacitors and to shut down the high voltage source. The existing protection system, which uses a thyratron for grounding the high voltage circuit, has been installed in the LHC about 20 years ago. The problem of "faulty shots" appears due to the higher energy of LHC compared to LEP, which may lead to unnecessary stops of the LHC due to the crowbar system. This paper presents two approaches under consideration to improve the thyratron’s performance and to use a solid state thyristor in high energy environment. The main objectives will be dissipate as little energy as possible in the arc and avoid "faulty shots".  
poster icon Poster THPPD056 [0.703 MB]