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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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