Resonance Control in SCRF Cavities
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
seminar surveyer
Active In SP
**

Posts: 3,541
Joined: Sep 2010
#1
20-10-2010, 11:08 AM




Resonance Control
in SCRF Cavities

Resonance Control in SCRF Cavities

SCRF cavities are designed with thin walls to maximize heat transfer to liquid He bath
The thin walls lack stiffness making the cavities susceptible to mechanical oscillations
Longitudinal oscillations can change the resonance frequency of the cavity
Oscillations can be excited
Deterministically (Lorentz Force)
Non-Deterministically (Microphonics)
Lorentz Force Detuning

Electromagnetic fields in the cavity cause the cavity wall to distort
Distortion changes the resonance frequency of the cavity
Effect proportional to the square of the field strength

CW-mode operation

Peak power increases with the fourth power of accelerating gradient:
Example: for Eacc=35MV/m up to 100-150% extra RF power:

-Over-sized Klystron

- More difficult control of RF (LLRF)

Lorentz Force Detuning

and RF Power Requirements
(for FlatTop~800us)

Microphonics
Noise sources (.e.g. pumps, cryo-system; seismic waves, etc. ) excite cavity vibrations
Tuners
Slow Tuner
Compensates for
Static Detuning Forces

Fast Tuner
Compensates for
Lorentz Force Detuning & Microphonics

Stepper motor changes length of the cavity to bring it to the desired resonance frequency

Techniques:
a) Piezoelectric actuators

b) Magnitostrictive actuators

c) Electromagnetic (superconductive)

Fast Tuner Technologies

PIEZOELECTRIC ACTUATORS

Commercially available from multiple sources
Typically used at room temperature (stroke~30mm for 40mm long Piezostack at RT)
Work at cryogenic temperatures with reduced stroke (6-10% of RT stroke ~ 4-5mm at 4K)
Deliver high forces ~5000N for 10*10mm2 cross-section
Actuator of main choice at many labs for detuning compensation studies

Double Piezo (DESY)

Single Piezo (FNAL)

DETUNING COMPENSATION

Resonant Excitation Method

Advantage: small piezo stroke amplified by mechanical resonance

Excitation electrical pulse on the piezoactuator

(control of in-advance timing and amplitude)


for more details, please visit
ilc-dms.fnal.gov/Workgroups/CryomoduleDocumentation/AES004/references/Resonance%20Control_for_N_Solyak.ppt

Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  IDENTIFICATION OF CONTROL OF A MAGNETIC LEVITATION SYSTEM PPT seminar flower 0 687 04-09-2012, 03:08 PM
Last Post: seminar flower
  Continuous phase stabilization and active interferometer control using two modes seminar flower 0 516 26-05-2012, 01:28 PM
Last Post: seminar flower
  Sliding-Mode Control of a Nonlinear-Input System: Application to a Magnetically Levit seminar surveyer 0 922 12-10-2010, 04:36 PM
Last Post: seminar surveyer
  Surface plasmon resonance projectsofme 0 649 08-10-2010, 03:21 PM
Last Post: projectsofme
  CONTROL OF NONLINEAR SYSTEMS REPRESENTED IN QUASILINEAR FORM full report seminar topics 0 847 31-03-2010, 07:53 PM
Last Post: seminar topics