Post on 16-Dec-2015
SPL tuning bench: status and results
Kai/Waqas
Setup
• Resonance frequency S11/S21 Measurement
• Field Flatness Bead Pull
Displacement measurements
1 2 3 4 5Strain Gages Input Port Pick-up
Bead
Name Pieces
1-MX840A QuantumX: DAQ module
1
1-WI/10MM-T Mini displacemnt transduc. WI/10mm,probe
4
Sensitivity Analysis
x – under straino - released
• Elastic limits vary from cell to cell due to pre-treatments and increase which each cycle plastic deformation range reduces (at the moment f < 30 kHz for all cells)
Elastic limits
Bead Size• Trade-off between sensitivity and linear
phase error• S21 one measurements for different bead
sizes and a network analyser that gets sick
step Bead size [mm] Lin. phase error*1 7.95 8.68%2 5.72 0.04%3 6.87 5.31%4 6.2 2.90%
*Linear phase error based on a fit with arctan function and compared with linear function
Tuning Procedure• Initial state of the Cavity
• Field flatness of 22 %• Resonance Frequency: 703.106 MHz
1
Bead pull measurement Frequency Correction
• Tuning to 703.2MHz decided due to limited deformation
Tuning Procedure
1
Tuning ProcedureInitial Cell 4 compressed
Cell 1 compressed Cell 2/4 pulled
Summary
• Tuning procedure elaborated and tested• heat treatment of the Cu Cavity (reset elastic
limits)• Further tuning of the test cavity afterwards• End cells should be tuned at the end• Upgrade of tuning bench yes/no?• Maximum frequency shift per cell +-170 kHz