BE-KT Innovation Day Octopus Temperature Mapping System for Cavity Diagnostics

1. 3 June 2012 BE-KT Innovation Day Prevessin, CERN, Switzerland BE-KT Innovation DayOctopus Temperature Mapping System for Cavity Diagnostics Kitty Liao BE-RF-SRF Kitty.Liao@cern.ch

2. 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 BE-KT innovation day Octopus Temperature Mapping System

3. 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 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) BE-KT innovation day Octopus Temperature Mapping System source: G. Ciovati, et al.,” Temperature mapping system for single cell cavities”, Fermilab, internal report (2005)

4. Background Mainstream systems The Octopus T-map Outlook & Summary Mainstream systems source: D. Reschke et al., THP016, LINAC08 source: J. Knobloch et. al, Rev. Scientific Instru. 65 (11) source: T. Tajima, LA-UR-09-02723, PAC09 β↑ β↓ BE-KT innovation day Octopus Temperature Mapping System

5. Octopus Temperature Mapping SystemDesign 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 BE-KT innovation day Octopus Temperature Mapping System

6. Background Mainstream systems The Octopus T-map Outlook & Summary Octopus Temperature Mapping SystemPrototype • 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) BE-KT innovation day Octopus Temperature Mapping System

7. Background Mainstream systems The Octopus T-map Outlook & Summary Octopus Temperature Mapping SystemPrototype • 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 12 ribbon cables for a single cell BE-KT innovation day Octopus Temperature Mapping System

8. 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)! BE-KT innovation day Octopus Temperature Mapping System