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New EPU Moves Into Sector 7 Print
Monday, 24 February 2014 11:20


The ALS MAESTRO project has just reached a significant milestone with the installation of a new elliptically polarizing undulator (EPU), representing the return of light to Beamline 7.0. MAESTRO is a new beamline facility comprising two photoemission branchlines and a dedicated custom EPU insertion device. The micro Angle-Resolved Photoemission Spectroscopy (ARPES) branchline is a continuation of the current Electronic Structure Facility and a new nanoARPES branchline will provide angle-resolved photoemission spectroscopy with sub-micron imaging capability. EPUs are magnetic devices that provide synchrotron radiation of tunable, i.e., linear or circular polarization, enabling controlled beamline experiments in the soft x-ray spectrum.

The new EPU will provide photons from 20-1000 eV to the MAESTRO beamline. With endstations for high-resolution ARPES, nanoARPES with an illuminated beam spot of 50 nm, Photoemission Electron Microscopy (PEEM), and a suite of networked sample preparation facilities, MAESTRO will provide an ideal probe of mesoscale electronic structures.

A team of ten ALS technicians and riggers positioned the 4.5-ton MAESTRO EPU in sector 7.0 of the main ring during the February maintenance shutdown. The device was moved into the ALS from Building 15, where the EPU’s magnetic field structure was shimmed. EPU commissioning is planned for March 2014.

The LBNL Engineering Division designed and oversaw production of the MAESTRO EPU. Work developing beamlines represents a lab-wide interdivision collaboration with notable support from Accelerator Fusion and Research Division (AFRD) Accelerator Physics team, the ALS scientific and technical staff. The design and production of an EPU represents technical contributions from roughly 20 scientists and engineers in addition to  industrial manufacturing support.