IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 1 of 13 BL 24 – CIRCE Photoelectron spectroscopy and microscopy

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 2 of 13 Outline Brief beamline description Photoelectron spectroscopy PEEM experimental station NAPP experimental station Detectors

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 3 of 13 CIRCE (BL24) is a variable polarization soft x-ray beamline for photoelectron microscopy and near ambient pressure spectroscopy, on two separate branches. The PEEM branch started regular user operation on October 17 th, 2012 The NAPP branch is commissioned but the end station has not been accepted yet. Beamline description NAPP top view PEEM NAPP PEEM side view APPLE II helical undulator vertical collimation plane grating monochromator refocusing branching & focusing

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 4 of 13 Beamline description PEEM branch flux (ph/s) resolution NAPP branch

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 5 of 13 E kin = h – E binding -  h e-e- monochromatic e-e- e-e- known photons energy, polarization, incidence angle + analysis photo-electrons energy, angle, (spin) + conservation rules sample properties composition chemical state depth profile electronic structure magnetic properties surface sensitive Photoelectron spectroscopy

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 6 of 13 Entrance slit into hemisphere Aperture 1 Aperture 2 Differential pumping sections Gap ≤ 1 mm Sample NAPP: Near Ambient Pressure Photoemission

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 7 of 13 NAPP experimental station UHV to 25 mbar Energy resolution < 10 meV Ultrapure gas dosing system Verdaguer et al., Langmuir, 2007

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 8 of 13 PEEM: PhotoEmission Electron Microscopy

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 9 of 13 PEEM experimental station lateral resolution: LEEM & UV-PEEM <10 nm XPEEM ~ 30 nm energy resolution < 0.2 eV diffraction &  -spot modes in situ evaporation & gas exposure Thin films La 2/3 Sr 1/3 MnO 3 /SrTiO 3 mimic substrate self-assembled terminations: La 2/3 Sr 1/3 O, MnO 2 XPEEM images at low energy cutoff: contrast inversion due to different work function J. Fontcuberta, C. Ocal, et al (Oct 2012)

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 10 of 13 NAPP detector MCD-9 9 x extended range Channel Electron Multipliers 10 8 amplification maximum 16.8 Mcps linear up to 10 Mcps Commercial alternatives: Micro Channel Plate + CCD Delay Line Detector (single event counting, 160ps, 3 MHz count rate)

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 11 of 13 PEEM detector MCP + in-air CCD 40 mm diameter PSF ~ 50 um gain 10 7 Pco.2000 (Sensor KAI-4021) Chip size = 15.2 x 15.2 mm2 Pixel = 2048 x 2048 Pixel size= 7.4 x 7.4 um2 560 nm = 45% full well capacity = 40 ke- dynamic range A/D = 14 bit, 73 dB readout noise = 9-14 e- rms 14.7 fps Anti-blooming >300 dark -12C = 0.01 e¯/pix·s UHV air CCD chip

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 12 of 13

IFAE-ALBA Meeting, December 13 th 2012BL24 - CIRCE 13 of 13 CIRCE are Lucía Aballe Virginia Pérez Carlos Escudero Michael Foerster Antonio Milán (controls) but also Josep Nicolás Eric Pellegrin and could not live without support from engineering alignment controls electronics …