1. Vibration Measurement Standards of Optical Components
Paw Kristiansen, FMB Oxford
Tuesday 21st October 2014
We make beamlines…

2. A vibrational number is meaningless without a frequency range
Temperature C vs F
It is not a community standard to specify frequency range (not in specifying requirements and not when (verbally) reporting vibrations)
My optical element vibrates at 100nrad – whel what Hz. When I told a headline number…

3. Motorized DCM motions 𝐑 𝒀,𝑿 Backplate 𝐑 𝑿 𝐁𝐫𝐚𝐠𝐠 𝐑 𝒀 Z Y
Energy range: 2.4 – 103 keV
Crystal pairs: Si 111 & Si 311
𝐑 𝒀,𝑿
Backplate Z
2nd crystal Y
Beam out
𝐑 𝑿 𝐁𝐫𝐚𝐠𝐠
Fixed offset, direct drive. Not a simple one it has all the motions…
Most channangeing DCM (except from a bend 2nd crystal)
Cryocooled
Beam in
1st crystal
𝐑 𝒀 Z Y

4. Relative pitch vibrations Absolute pitch vibrations
Red dot is pivot points
Dotted line is the back plate
Ad: 300 nrad-> 2 meV at 4 keV

5. 0-2.5kHz relative, 0-1.6kHz encoder
Roll
Backplate
Encoder ring
Pitch
Goniometer
Roll Z
Air actuated brake release 750 Nm (1400 Nm)
Defying the nature of a direct drive motor. Also mention Brake.
A braked group and a servoing group.
Ferromagnetic seal X
0-2.5kHz relative, 0-1.6kHz encoder

6. Less under 120 Hz
PID settings for the 50Hz vibration

7. About a factor of 3…
Headline number

8. 0-25kHz absolute, 0-1.6kHz encoder

9. Torsion spring effect 0-25kHz absolute, 0-1.6kHz encoder BackplateX Z
Backplate
Ferromagnetic seal
Encoder ring
Goniometer
Roll
Pitch
The interferometer is itself also vibrating…
0-25kHz absolute, 0-1.6kHz encoder

11. Almost a factor of 2

12. Relevant frequency range…?
2-100 Hz: 29 nrad RMS ≈> 1300 km
0-2.5 kHz: 100 nrad RMS ≈> 400 km
Laser aiming…
I’m not say that the frequency range always should be max…
E.g. (differs between beamlines!)
XAFS: 1 Hz – 1 kHz
Crystallography: 0.1 – 200 Hz
RIXS: Hz

13. New vibrational unit? brilliance= photons s × mrad 2 × mm 2 ×0.1%BW
Vert generic terme
′vibton′= 𝑓(RMS) 𝑓(s) ×𝑓 Hz max ) × 𝑓(Hz min ×𝑓 cooling power

14. Thanks for your attention-
Questions..?
The shown results are being published…
If you have qustions or you want to build a beamline…
stand 8