Insertion Devices

Latest Installation: REIXS EPU

April 15, 2008
Installation of the REIXS EPU occurred during the December 2007 shutdown, preliminary studies have looked at effects on the stored current and further development of feed forward lookup tables for correction coils is in progress.  Commissioning of beamline is awaiting installation of all beamline components and will begin in summer 2008.

REIXS EPU (right) Installed beside SM EPU (left)

REIXS EPU (right) Installed beside SM EPU (left)

REIXS EPU support structure in place in the magnet measurement lab

REIXS EPU support structure in place in the magnet measurement lab

A special five-magnet chicane will used in one straight to allow for light from two elliptically polarizing undulators to be independently directed towards either or both beamlines to allow for fast polarization switching.

There are nine 5.5 m long straight sections in the CLS storage ring available for insertion devices. The optimum length for an insertion device at the CLS is around 1.5 m. This allows two permanent magnet undulators to be installed in the same straight section. A three magnet chicane is used to create a small angular separation in the beams. X-ray beams share the same front end and are separated outside the tunnel.

5-chicane arrangement of EPUs in Straight 10.

There are nine 5.5 m long straight sections in the CLS storage ring available for insertion devices. The optimum length for an insertion device at the CLS is around 1.5 m. This allows two permanent magnet undulators to be installed in the same straight section. A three magnet chicane is used to create a small angular separation in the beams. X-ray beams share the same front end and are separated outside the tunnel.

SGM and VLS-PGM installed in Straight 11 

SGM and VLS-PGM installed in Straight 11          

Hybrid in-vacuum undulator magnetic structure with flip coil.

Hybrid in-vacuum undulator magnetic structure with flip coil.

Installed devices

Phase 1
In-house built undulators :

Other Devices:

Phase 2
In-house built undulators :

Other Devices:

Upcoming devices

Plans for Phase 3 insertion devices are still under development.

Magnet Mapping Facility

The magnet measurement lab is located between the booster ring and the storage ring. It is used primarily for the assembly, measurement and adjustment of the magnetic structures used in permanent magnet insertion devices. It is also used for the measurement and calibration of other CLS electromagnets.

ecently constructed SM SPU in place in magnet mapping facility.

Recently constructed SM SPU in place in magnet mapping facility. In front is hall probe.

Measurement of magnetic fields is performed with a flip coil and hall probe.

The flip coil is used to measure the first field integrals as well as multipole structure. It consists of two servo-motor driven rotating stages supported by two tables with linear stages controlled by stepper motors. A 20-turn coil of 80 micron-diameter wire strung between two bobbins on the rotating stages, the coil diameter is controlled with ring clamps. The measure the field integrals the coil is rotated in steps from 0 to 360 degrees and back, the induced EMF integrated by a voltmeter gives eight combinations of vertical and horizontal integrals. The standard deviation for such a measurement with a 5 mm coil is about 2 G-cm. The linear stages can be stepped over 300 mm horizontally or vertically to provide the normal and skew magnetic multipoles.

A 3-element hall probe is used to map detailed magnetic structure. The hall probebench is a 6 m long granite block from Anorad Europe, ground to a very high flatness. On this is mounted an (x,y)-table supporting the 3-element hall probe. The measurement length is 4.5 m longitudinally and 30 cm horizontally and vertically. The table is driven by a linear motor with a 0.1 micron resolution optical ruler and the measurements system is triggered with a laser interferometer. Field measurements are taken on the fly with table velocities up to 40 mm/s. The reproducibility of the magnetic measurements is very good. Multiple scans were made and the corresponding electron orbits as calculated from ESRF analysis software B2E showed a spread in the orbits at the end of the undulator structure to be about 0.2 microns.

Hall probe bench at Anorad

Hall probe bench at Anorad

The excellent straightness and small roll, pitch and yaw of the hall probe bench in combination with the good resolution of the optical rulers make it a very good coordinate measuring device. The bench is used, with a dial indicator instead of the hall probe, to precisely place the magnets on the support girders during assembly.

The facility includes a calibration dipole and nuclear magnetic resonance probe capable of producing and measuring fields up to 2.5 T with high precision. This is used to calibrate the hall probe elements.

The four Phase-1 undulators have been successfully assembled and shimmed in-house. The magnetic structures are shimmed to minimize phase-angle error to provide highly coherent photons and to minimize multipole field errors which negatively impact the stored electron beam. Small first and second field integrals are corrected with attached correction coils.