1. Storage ring optics characterization – the basics
Beam Diagnostics
DCCT
Strip lines
BPMs
Scrapers
Synchrotron light monitors
Loss monitors
Measuring tunes, b, h, chromaticity, a?
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

2. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Photon factory DCCT
T. Honda et al., EPAC98
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

3. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
SPEAR3 DCCT
BEAM DIRECTION
INSULATED BY
CERAMIC BUSHINGS
LOW FREQUENCY COMPONENT
ISOLATED BY .010” GAP
SENSOR ISOLATED
ON ONE END
CERAMIC BREAK PREVENTS
CURRENT FROM FLOWING
THROUGH BELLOWS
.010 GAP
TOROID
image current
TOROID
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

4. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
DCCT (or PCT) circuit
Bergoz PCT
7 kHz
Nonlinear ferrite core
14 kHz
beam
J.A. Hinkson, LBNL
The DC bias current is adjusted to remove the 2nd harmonic (14 kHz) response of toroid. The beam current is proportional to the DC bias current.
Ferrite core Xsection
Simplified circuit, K. Unser, 1992
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

5. Beam position monitors
Electron BPM buttons sample electric fields; striplines couple to electric and magnetic fields.
Examples of photon BPMs:
Copper fluorescence bpm:
Split ion chamber:
Tungsten blade monitor:
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

6. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Loss monitors
Kuske measurements made with scintillator and photo multiplier.
Bergoz
Kuske measurements made with scintillator and photo multiplier.
Kuske et al., PAC01.
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

7. Beam size measurements: Scrapers
Synchrotron light monitors
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

8. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Beam frequencies
Beam frequencies
Importance, global measure of optics.
First measurements made of ring.
Instabilities
If you have a single bunch with charge q in a storage ring with a revolution time T0, the signal on an oscilloscope looks like
where I’m assuming a zero-length bunch. A spectrum analyzer would see the Fourier transform of this, w0 T0
Time
Frequency
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

9. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
frequency (1/sl)
For SPEAR3, c/sl = 67 GHz.
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

10. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Betatron tune
Frequency fb f0
Integer and ½ integer ambiguities
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

11. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Synchrotron tune
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

12. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Measured spectra
HLS tune meas., Sun et al. PAC01
Multibunch spectra, instabilities, Sebek, Friday.
Courtesy J. Byrd
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

13. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
More on spectrum
Turn by turn measurements, FFT, NAFF,
betatron phase (Tuesday)
Nonlinear dynamics (tune vs. amplitude; tune vs. closed orbit; Thursday)
Impedance measurements (Friday)
Beta function measurements
Chromaticity
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

14. Beta function measurement
Dnu=betaKL/4pi
Measurement issues
Keep orbit constant
Hysteresis
Saturation
Sometimes cannot vary individual quadrupoles
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

15. SPEAR b-function correction
before
after
Courtesy Heinz-Dieter Nuhn
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

16. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Other b measurements
Fit response matrix Mij = sqrt(…), Y. Chung et al., PAC’93
Derive from betatron phase measurements (Tuesday lecture)
Beam size measurement
Minty and Spence, PAC’95
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

17. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Dispersion
Dispersion is the change in closed orbit with a change in electron energy.
The energy can be changed by shifting the rf frequency.
(a = momentum compaction)
So the dispersion can be measured by measuring the change in closed orbit with rf frequency.
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

18. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Dispersion
X-Ray Ring h indicates large Kx errors
Dispersion distortion can come from quadrupole or dipole errors.
Vertical dispersion gives a measure of vertical bending errors or skew gradient errors in a storage ring.
PEPII hx and hy measurement
Uli Wienands
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

19. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Chromaticity
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek

20. Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek
Momentum compaction
Beam dynamics in IDs
Beam-based Diagnostics, USPAS, June 23-27, 2003, J. Safranek