mechanical properties of spoke cavities - cornell · pdf filejuly 12, 2005 2 collaborators anl...
TRANSCRIPT
![Page 1: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/1.jpg)
A U.S. Department of Energy Office of Science LaboratoryManaged by The University of Chicago
Argonne National Laboratory
Mechanical Properties of Spoke Cavities
Zachary ConwayPhysics Division
UIUC/ANLJuly 12, 2005
![Page 2: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/2.jpg)
2July 12, 2005
Collaborators
ANL- Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann
AES- John Rathke, Tom Schultheiss
Energen- Chad Joshi, Chiu-Ying Tai
![Page 3: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/3.jpg)
3July 12, 2005
Spoke Cavity Mechanical Properties
SC cavities typically have both a small loaded and a small intrinsic bandwidth. This makes them very sensitive to mechanical deformations which result in frequency variations.
Mechanical Properties:- cw operation => microphonic induced noise.- pulsed operation => Lorentz Detuning.
![Page 4: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/4.jpg)
4July 12, 2005
Spoke Cavity Mechanical Properties
Methods of controlling amplitude and phase errors:- Overcoupling- Reactive Tuners- Fast Mechanical Tuners
- Piezoelectric actuated- Magnetostrictive actuated
![Page 5: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/5.jpg)
5July 12, 2005
Outline
Cavity mechanical properties. Fast mechanical tuners.
![Page 6: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/6.jpg)
6July 12, 2005
β = 0.4 Double Spoke Microphonics
Results of first cold test of a production model double spoke cavity with an integral stainless steel housing holding the liquid helium bath.∆f/∆P = -76 Hz/torr
σrms=5.3Hz
![Page 7: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/7.jpg)
7July 12, 2005
β = 0.5 Triple Spoke Cavity
β=0.5 triple spoke cavity designed* to minimize ∆f/∆P.Designed to balance the electric and magnetic field contributions to frequency shifts due to uniform external pressure.* Modeling performed by AES.
![Page 8: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/8.jpg)
8July 12, 2005
β = 0.5 Triple Spoke Microphonics
Cavity tested in a realistic accelerator environment. ∆f/∆P = -12.4 Hz/torr
σrms=1.04Hz
![Page 9: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/9.jpg)
9July 12, 2005
β = 0.5 Triple Spoke Cavity
measured ∆f/∆P(predicted) = -12.4(-8.7) Hz/torr ∆f/∆P = -6.3(-4.7) Hz/torr
∆f/∆P = -2.5(-0.3) Hz/torr ∆f/∆P = -0.5(+5.4) Hz/torr
![Page 10: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/10.jpg)
10July 12, 2005
Changing Gears
Finished talking about microphonics.
I am now going to talk about Lorentz detuning.
![Page 11: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/11.jpg)
11July 12, 2005
β = 0.4 Double Spoke Lorentz Transfer Function
KL=-1.9 Hz/(MV/m)2
![Page 12: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/12.jpg)
12July 12, 2005
β = 0.5 Triple Spoke Lorentz Transfer Function
KL=-6.5 Hz/(MV/m)2
![Page 13: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/13.jpg)
13July 12, 2005
Frequency Variation Due to Pulsed FieldsPrediction
( ) ωωω ω de ti−∞
∞−∫ ∗= )(Input)(FunctionTransfer )Response(t
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14July 12, 2005
Spoke Cavity Fast Mechanical Tuning
![Page 15: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/15.jpg)
15July 12, 2005
Piezoelectric Actuated Fast Tuner
Response time <1ms.
Layered piezo-ceramic material electrically connected in parallel operating at ~20K with a resolution of 2nm purchased from Physik Instrumente.
Not designed for high frequency operation.
11”
![Page 16: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/16.jpg)
16July 12, 2005
β = 0.4 Double Spoke Piezo Transfer Function
![Page 17: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/17.jpg)
17July 12, 2005
β = 0.5 Triple Spoke Piezo Transfer Function
![Page 18: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/18.jpg)
18July 12, 2005
Magnetostrictive Actuated Fast Tuner
Magnetostrictive actuator designed and built by Energen, Inc and slated to be tested at ANL.
Response time <6ms.
Magnetostrictive rod coaxial with an external solenoid operating at 4K.
4.6”
9”
![Page 19: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/19.jpg)
19July 12, 2005
Future Work
Measure microphonic induced noise spectrum of β = 0.5 triple spoke cavity to measure the effect of modifying the support ribs.
Pulse a spoke cavity and measure the frequency variation.
Use fast mechanical tuners to reduce frequency variations due to microphonics and the Lorentz force.
![Page 20: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/20.jpg)
20July 12, 2005
Lorentz Transfer Function
Amplitude modulated RF fields are be expressed as:
tifii
iexHtAtxH π2)()(),( rrrr=
∑=i
ii xttxu )()(),( rrrr ξη
tifii
iexEtAtxE π2)()(),( rrrr=
• The local displacement of a cavity surface can be expressed as:
![Page 21: Mechanical Properties of Spoke Cavities - Cornell · PDF fileJuly 12, 2005 2 Collaborators ANL - Ken Shepard, Mike Kelly, Joel Fuerst, Mark Kedzie, Gary Zinkann AES - John Rathke,](https://reader031.vdocuments.site/reader031/viewer/2022030506/5ab3e03b7f8b9a156d8b5b71/html5/thumbnails/21.jpg)
21July 12, 2005
Frequency Shift
∑∫
∫
⎥⎦
⎤⎢⎣
⎡+
⎟⎟⎠
⎞⎜⎜⎝
⎛ Ω−−Ω
=∆
∞
∞−
i
V
MECHi
ii
iwt
ii xdxHxEc
dw
Qwiw
e
MtAftf
)()(12)()(
32
00
2
00
222
0rrrr
εµ
π
22
00
2
00 )()()( ⎟⎟⎠
⎞⎜⎜⎝
⎛⋅⎥⎦
⎤⎢⎣⎡ −∫
∆
adxxExH iV
rrrrvrrξεµx