Visible-light beam size monitors using synchrotron radiation at CESR

Abstract

A beam profile monitor utilizing visible synchrotron radiation (SR) from a bending magnet has been designed and installed in Cornell Electron-Positron Storage Ring (CESR). The monitor employs a double-slit interferometer to measure both the horizontal and vertical beam sizes over a wide range of beam currents. By varying the separation of the slits, beam sizes ranging from 50 to 500 um can be measured with a resolution of approximately 5 um. To measure larger beam size (> 500 um), direct imaging can be employed by rotating the double slits away from SR beam path. By imaging the pi-polarized component of SR, a small vertical beam size (~70 um) was measured during an undulator test run in CESR, which was consistent with the interferometer measurement. To measure the bunch length, a beam splitter is inserted to direct a fraction of light into a streak camera setup. This beam size monitor measures the transverse and longitudinal beam sizes simultaneously, which is successfully used for intrabeam scattering studies. Detailed error analysis is discussed.Comment: 26 pages, 13 figure

Intrabeam scattering studies at the Cornell Electron Storage Ring Test Accelerator

“…The horizontal beam size monitor also undergoes direct calibration with a source of known size [17].…”

Source size measurement options for low-emittance light sources

“…The use of double-slit interferometry to measure the beam size in particle accelerators was first developed by Mitsuhashi at KEK in Japan [9]. Since then, this system has been used at many synchrotron facilities as a way to measure the electron beam sizes [10,11,[21][22][23][24][25][26]. This system is mostly implemented in the visible light regime (wavelength of 400-600 nm) at third-generation light sources because of (i) the availability of high-quality visible light optics and (ii) a relatively large coherence length of the visible light.…”

Measurement and compensation of horizontal crabbing at the Cornell Electron Storage Ring Test Accelerator

“…The uncertainty in the location of the source point, given by the depth of field, is 0.35 m [12]. This contributes an additional AE3.2 μm systematic uncertainty to the "Base" lattice simulation results.…”

“…Horizontal beam size is measured using an interferometer which images synchrotron radiation from a soft bend [12]. Bunch length measurements are made with a streak camera using synchrotron radiation from the same bend [13].…”