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Test of a tuning system for Spoke cavity

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Good mechanical behaviour at cryogenic temperatures. Very low ... Ball screw : Stainless steel with MoS2 solid lubricant and ceramic ... hysteresis ... – PowerPoint PPT presentation

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Title: Test of a tuning system for Spoke cavity


1
Test of a tuning system for Spoke cavity
  • Nicolas GANDOLFO

2
Spoke Cavity
Spoke SC cavity
3
Spoke Cold Tuning System
  • Spoke Cavity parameters
  • Resonance 352 MHz
  • Sensitivity 1 MHz/mm
  • Bandwidth 250 Hz
  • CTS parameters
  • Resolution 2 nm
  • Range 4 mm
  • Nominal strength 600 kg
  • Hostile environment
  • Low pressure 10-7 mbar
  • Cold temperature 2K
  • X-Ray emission

3D View of the system on its Spoke cavity
4
Mechanical study
  • Components
  • Main material Stainless Steel 304L
  • Good mechanical behaviour at cryogenic
    temperatures
  • Very low magnetic permeability
  • Easy machining
  • Good ratio quality/price
  • Mechanical joints
  • Ball joint Uniflon lubricant
  • Standard bearings /!\
  • Ball screw Stainless steel with MoS2 solid
    lubricant and ceramic balls
  • Actuators
  • Stepper motor Phytron
  • Piezoelectric actuator type multistack
  • CEA Soleil double lever arm principle

3D View
5
Instrumentation diagram
  • Bipolar stepper motor
  • Driving by an constructor amplifier device
  • Control from a computer
  • Serial communication RS232
  • Motor control software realized on LabView
  • Regulation using a numeric PID and loopback
    information provides by RF electronic stage

f
?f
TCP/IP
PC Computer
LabView Software Control
RS232
Amplifier
M
PID
6
Cryogenic test results
  • Excellent repeatability
  • Sensitivity found 0,95 Hz/pas (calculated
    1,38 Hz/pas)
  • No mechanical hysteresis measurable
  • Successful regulation with a stable frequency
    (variations lt ?f 50 Hz)

Motor control (in motorstep)
Frequency shift error (in Hz)
Curves showing CTS efficiency
7
Piezoelectric actuators study
Noliac Piezoelectric actuators
  • Specifications
  • Dimensions 36x10x10 mm
  • Vacuum compatibility (10-7 mbar)
  • Strength capability 4 kN
  • Stiffness 100 kN/mm
  • Displacement range
  • 36 µm _at_300K
  • 3 µm _at_4K

8
Piezoelectric actuators study
  • Mechanical precautions !
  • No shear, torsion, bending forces
  • Hemispherical supports with high machining
    precision
  • Nominal prestress of 40MPa
  • Active tuning system for each actuator by heating
    an aluminum part which provides controlled
    strength

Next step Test _at_4K scheduled for begin of
2008
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