be-kt innovation day octopus temperature mapping system for cavity diagnostics
DESCRIPTION
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 [email protected]. Background Mainstream systems The Octopus T-map Outlook & Summary. Presentation Structure. - PowerPoint PPT PresentationTRANSCRIPT
BE-KT Innovation DayOctopus Temperature Mapping System for
Cavity Diagnostics
Kitty Liao BE-RF-SRF
3 June 2012 BE-KT Innovation Day Prevessin, CERN, Switzerland
BE-KT innovation day Octopus Temperature Mapping System
Presentation Structure
1. Background : Cavity diagnostics for quench2. Mainstream (Existing) systems3. NEW- The Octopus Temp. Mapping system4. Outlook & Summary
Background Mainstream systems The Octopus T-map Outlook & Summary
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Temperature mapping background • 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
HNiobium bulkTc =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)
Superfluid He (2 K)
source: G. Ciovati, et al.,” Temperature mapping system for single cell cavities”, Fermilab, internal report (2005)
Field emission
Quench Loss distribution
Precursor
Background Mainstream systems The Octopus T-map Outlook & Summary
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Background Mainstream systems The Octopus T-map Outlook & Summary
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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
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• 1/3 Octopus flexible polymide (Kapton) PCB - sensor res. 20 (equator) ~ 34 mm - pre carved space for second sound travel - multiplexers IC
Octopus Temperature Mapping SystemPrototype
• Allen-Bradley sensor package - dedicated glass fiber holder - concealed manganin wires in stycast - stable pins on the sides - ~3000 (5 cell)
Background Mainstream systems The Octopus T-map Outlook & Summary
03/06/2013 K.Liao
H. Piel & R. Romijn, CERN/EF/RF 80-2 (1980)
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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
Resistors
MUX µc boards
1 cell 576 144 65 cell 2880 720 30
12 ribbon cables for a single cell
PCTemp maps
Background Mainstream systems The Octopus T-map Outlook & Summary
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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)!
Background Mainstream systems The Octopus T-map Outlook & Summary
03/06/2013 K.Liao