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Beamline 4.0.2

Magnetic and biochemical spectroscopy

Operational	Now
Source characteristics	5.0-cm-period elliptical polarization undulator (EPU5)
Energy range	80–1900 eV
Monochromator	Variable-included-angle PGM
Calculated flux (1.9 GeV, 400 mA)	1 x 10¹³ photons/s/0.1%BW at 800 eV [Value reported is the merit function, flux = total flux x (degree of circular polarization)².]
Resolving power (E/ΔE)	5,000-10,000 (at source-size limit; energy-dependent) >25,000 (64 eV, 10-mm entrance/exit slits)
Special notes	Polarization is user selectable; linear polarization continuously variable from horizontal to vertical; left and right elliptical (or circular) polarization.
Endstations	Advanced photoelectron spectrometer/diffractometer L-edge chamber with superconducting spectrometer XMCD chamber (6T, 2K) Eight-pole electromagnet
Local contact	Name: Elke Arenholz Advanced Light Source Phone: (510) 486-4834 Fax: (510) 486-7588
Spokesperson	Name: Stephen P. Cramer University of California, Davis/Berkeley Lab Phone: (510) 486-4720 Fax: (510) 486-5664
Beamline phone number	(510) 495-2041

Endstation	Advanced photoelectron spectrometer/diffractometer
Characteristics	Rotatable analysis chamber, two-axis variable-temperature sample goniometer with 3-D translation operating between 150 and 2000 K; new goniometer extending to 10 K in mid-2002
Detectors	Scienta ES 200 electron spectrometer with micro-Mott spin detector (now) and Scienta XES 300 x-ray emission spectrometer (early 2002)
Spot size at sample	1 mm (h) x 0.1 mm (v), larger if defocused
Samples
Format	UHV-compatible solids up to 10 mm in diameter and 1-2 mm thick
Preparation	Knudsen-cell thin-film evaporation, ion sputtering, annealing, LEED, loadlock sample insertion, in-situ cleaving and magnetization
Sample environment	UHV, approximately 1 to 2 x 10^-10 Torr
Scientific applications	Electronic and magnetic properties at surfaces and interfaces, atomic and magnetic structures near surfaces and at buried interfaces, structural and magnetic phase transitions
Experimental techniques	High-resolution, angle-resolved photoelectron spectroscopy, diffraction and holography; x-ray absorption and x-ray emission spectroscopy
Local contact/ Spokesperson	Name: Charles Fadley Affiliation: Univ. of California, Davis/Berkeley Lab Phone: (510) 486-5774 Fax: (510) 486-5530

Endstation	L-edge chamber with superconducting spectrometer
Detectors	Array superconducting tunnel junction fluorescence detector; sample current
Spot size at sample	1 mm (h) x 0.1 mm (v), larger if defocused
Samples
Format	Dried protein films, powders, thin films
Preparation	Proteins dried on Al₂O₃ disks, often in inert atmosphere; model compounds usually as powder on carbon tape
Sample environment	UHV, (10^-8 to 10^-9 Torr), cooling down to ~15 K possible
Special notes	Also analysis of wet and/or air-sensitive samples
Scientific applications	Active sites in metalloproteins, enzymatic mechanisms
Experimental techniques	Fluorescence-detected absorption spectroscopy
Local contact	Name: Stephan Friedrich Phone: (510) 486-7319 Fax: (510) 486-5664
Spokesperson	Name: Stephen P. Cramer Affiliation: Univ. of California, Davis/Berkeley Lab Phone: (510) 486-4720 Fax: (510) 486-5664

Endstation	XMCD chamber (6T, 2K)
Characteristics	6-Tesla superconducting magnet, 2 K sample temperature
Detectors	30-element germanium fluorescence detector; sample current
Spot size at sample	1 mm (h) x 0.1 mm (v), larger if defocused
Samples
Format	Solids, powders, dried liquid films up to 5 x 5 mm
Sample environment	UHV
Scientific applications	Spectroscopy on proteins and model compounds
Experimental techniques	XMCD, L-edge spectroscopy
Local contact	Name: Simon George Phone: (510) 486-6094 Fax: (510) 486-5664
Spokesperson	Name: Stephen P. Cramer Affiliation: Univ. of California, Davis/Berkeley Lab Phone: (510) 486-4720 Fax: (510) 486-5664

Endstation	Eight-pole electromagnet
Characteristics	Magnetic fields up to 0.9 T can be applied in any direction relative to the incoming x-ray beam
Detectors	Total electron yield, total fluorescence yield, transmission
Spot size at sample	0.8 (h) x 0.1 (v) mm , larger if defocused
Samples	Solid samples
Sample environment	10-6 to 10-9 Torr, 15 to 450 K
Scientific applications	Spectroscopy on ferro- and antiferromagnetic materials
Experimental techniques	XAS, XMCD, XMLD measurements
Local contact/spokesperson	Name: Elke Arenholz Affiliation: Advanced Light Source Phone: (510) 486-4834 Fax: (510) 486-7588 Email: earenholz @lbl.gov

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