SURF's up at NBS: A Progress Report

Spontaneous coherent microwave emission and the sawtooth instability in a compact storage ring

“…Later, Carr et al [3] reported the detection of spontaneous coherent synchrotron radiation in the mm wavelength range at the National Synchrotron Light Source VUV ring at Brookhaven National Laboratory. The period of the microwave bursts at SURF coincided strikingly with the period of bunch length relaxation oscillations, the latter first reported by Rakowsky [4,5], strongly suggesting a connection between the two effects. In this paper, we report on detailed measurements of the microwave intensity carried out while simultaneously collecting signals from a capacitive beam monitor electrode (BME) and from a photodiode system after SURF was upgraded to version III [6].…”

“…Relaxation oscillations of the bunch length have long been observed in the SURF ring, first reported by Rakowsky [4,5]. The period of these oscillations is observed to coincide with the period of the microwave bursts [1,2] both in broad and fine temporal detail, strongly suggesting a correlation.…”

Longitudinal instability studies at the SURF II storage ring at NIST.

“…The phase shifter was installed after the papers of Refs. [1] [2]. At specific values of the phase, the instability could be excited with as little as 7 mA of beam, albeit less severely than at higher currents ( Fig.…”

Diffraction and depths-of-field effects in electron beam imaging at SURF III

“…For this reason, the vertical betatron oscillation is excited in SURF to extend the vertical dimension of the beam. At SURF, this is called applying fuzz [13] to the beam because it induces random vertical motion of the electrons. Beam-size results for three different fuzz conditions at 284.4 MeV electron energy are listed in Table 3.…”