Kitty Liao BE-RF-SRF Kitty.Liao@cern.ch 3 June 2012 BE-KT Innovation Day Prevessin, CERN, Switzerland BE-KT Innovation Day Octopus Temperature Mapping System for Cavity Diagnostics Kitty Liao BE-RF-SRF Kitty.Liao@cern.ch

Presentation Structure Background Mainstream systems The Octopus T-map Outlook & Summary Presentation Structure Background : Cavity diagnostics for quench Mainstream (Existing) systems NEW- The Octopus Temp. Mapping system Outlook & Summary 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System

Temperature mapping background Background Mainstream systems The Octopus T-map Outlook & Summary Temperature mapping background H Superfluid He (2 K) Goal - achieve high accelerating gradient 704 MHz cavities for the SPL @ CERN (244 x 5-cell β =0.6 & β =1 cavities) - quality control Limitation - cavity quench: at a defective (quench spot) - thermal breakdown Solution - the first system: in CERN (1981) for 500 MHz LEP cavities - 120 Ω , ¼ W Allen-Bradley carbon resistors , rotating motor Niobium bulk Tc =9.2 K Field emission Quench Loss distribution Precursor source: Ph. BERNARD, Nuclear Instruments and Methods 190 (1981), ‘Temperature Mapping on a Superconducting RF Cavity in Subcooled Helium by H. Piel & R. Romijn, CERN/EF/RF 80-2 (1980) 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System source: G. Ciovati, et al.,” Temperature mapping system for single cell cavities”, Fermilab, internal report (2005)

BE-KT innovation day Octopus Temperature Mapping System Background Mainstream systems The Octopus T-map Outlook & Summary Mainstream systems Rotating Fixed scan time slow fast sensor few many accuracy - better flexibility x source: D. Reschke et al., THP016, LINAC08 LA-UR-09-02723, PAC09 source: T. Tajima, source: J. Knobloch et. al, Rev. Scientific Instru. 65 (11) β↑ β↓ 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System

Octopus Temperature Mapping System Design Concept & Features For SPL type cavities (=0.6, =1) Octopus inspired Flexibility, time saving  good contact and use on different beta cavities Allen-bradley sensor package (100 Ω, 1/8W, raw resistor ΔR/ΔT≈ 758 Ω/K)  75.8Ω/100 mK Fixed sensor pattern more accurate Multiplexer IC on printed circuit board  reduce cross talk 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System

Octopus Temperature Mapping System Prototype Background Mainstream systems The Octopus T-map Outlook & Summary Octopus Temperature Mapping System Prototype 1/3 Octopus flexible polymide (Kapton) PCB - sensor res. 20 (equator) ~ 34 mm - pre carved space for second sound travel - multiplexers IC H. Piel & R. Romijn, CERN/EF/RF 80-2 (1980) Allen-Bradley sensor package - dedicated glass fiber holder - concealed manganin wires in stycast - stable pins on the sides - ~3000 (5 cell) 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System

Octopus Temperature Mapping System Prototype Background Mainstream systems The Octopus T-map Outlook & Summary Octopus Temperature Mapping System Prototype Acquisition board outside the cryostat - calibration (at 4 K and 2 K) - measure resistance, process data - send to PC, show map - post process (real time) to see quench development PC Temp maps   Resistors MUX µc boards 1 cell 576 144 6 5 cell 2880 720 30 12 ribbon cables for a single cell 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System

BE-KT innovation day Octopus Temperature Mapping System Background Mainstream systems The Octopus T-map Outlook & Summary Outlook & Summary Temperature mapping system is essential for quench localisation & understanding cavity performance. The octopus Tmap is designed with features to solve problems with shape difference and with better performance – now at the prototyping stage. The first 1/3 prototype hoped to be tested by end of July. Further adjustment and modification for full 5 cell SPL structure/ LHC cavities/ Crab cavities Possibilities outside CERN in HEP: replacement for old style non-flexible temperature mapping systems? Man-power needed and manufactures for making the sensors! The needs you! Stephane Rey BE-RF (microprocessor programme and circuits) and me (end of July)! 03/06/2013 K.Liao BE-KT innovation day Octopus Temperature Mapping System