Results from a prototype chicane-based energy spectrometer for a Linear Collider

Abstract

The International Linear Collider (ILC) and other proposed high energy e + e − machines aim to measure with unprecedented precision Standard Model quantities and new, not yet discovered phenomena. One of the main requirements for achieving this goal is a measurement of the incident beam energy with an uncertainty close to 10 −4 . This article presents the analysis of data from a prototype energy spectrometer commissioned in 2006-2007 in SLAC's End Station A beamline. The prototype was a 4-magnet chicane equipped with beam position monitors measuring small changes of the beam orbit through the chicane at different beam energies. A single bunch energy resolution close to 5 · 10 −4 was measured, which is satisfactory for most scenarios. We also report on the operational experience with the chicane-based spectrometer and suggest ways of improving its performance.

The International Linear Collider Technical Design Report - Volume 4: Detectors

“…When combining all the BPM stations to measure the precision of the orbit over the whole ESA-chicane beamline, a resolution of 0.8 µm in x and 1.2 µm in y was achieved [52]. This translates to a relative energy resolution of 5.5 · 10 ≠4 [53].…”

Cavity beam position monitor system for the Accelerator Test Facility 2

“…CBPMs have been successfully tested in numerous experiments, which have consisted of either closely spaced triplets [8,9] or used with specialized optics configurations, like a ballistic beam in the case of [10,11]. Three full production systems have been operating at LCLS [12], FERMI@ELETTRA [13] and XFEL/Spring-8 recently started commissioning [14].…”

Polarisation and beam energy measurement at a linear e+e−collider

“…The setup allowed for stable measurements on O(1 µm) over one hour and a resolution of the beam orbit reconstruction of 0.8 µm/1.2 µm in x/y direction has been reported [20]. In a further study, an energy resolution for a single bunch measurement of ∆E/E = 0.05% has been determined and several issues for further improvement of the setup were identified [21]. Thus, the targeted precision seems to be in reach.…”