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BL20 - LOREA

ANGLE RESOLVED PHOTOEMISSION SPECTROSCOPY (ARPES)

ALBA BEAMLINES

IM_ExperimentalHall

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DESCRIPTION

LOREA will be a beamline devoted to electronic structure investigation by means of Angle Resolved Photo-Emission Spectroscopy (ARPES). The beamline photon energy range is 10-1000 eV with tunable polarization as produced by an APPLE II helical undulator. Thanks to a wide energy range and a high photon flux, LOREA will be suitable for high resolution VUV ARPES investigation in the range of 10-200 eV, with the possibility to detect the electron spin orientation (SR-ARPES) and to extend the ARPES measurements in the 200-600 eV energy range (soft X-ray ARPES). In addition, core level photoemission, resonant photoemission and X-ray absorption spectroscopies will be accessible in the whole energy range. 

IM_LOREAStaff

LOREA Staff, from left to right: Debora Pierucci (beamline scientist), Federico Bisti (beamline scientist), Massimo Tallarida (beamline responsible).

 

STATUS

LOREA is under construction and will be in operation in 2020. 


The undulator was installed in July 2017, and a first commissioning was done in October 2017 with low ring current (25 mA).

IM_LOREAUndulator1  IM_LOREAUndulator2

Undulator installation, July 2017.


The lead hutch was installed in September 2017. The front end was installed in November 2017.

IM_LOREAFrontEnd1  IM_LOREAFrontEnd2

IM_LOREAFrontEnd3  IM_LOREAFrontEnd4

(Top panels) Front end and (Bottom panels) Lead hutch installations.

 

TECHNICAL SPECIFICATIONS 

Photon energy range 10-1000 eV
Polarization Variable (left- and right-handed circular, linear horizontal and vertical)
Resolving power >  104 in the whole range
Photon flux

   1013 ph/s/0.1%BW @ hν = 10-350 eV 

> 1012 ph/s/0.1%BW @ hν = 350 - 1000 eV

Beam spot size at sample position (V×H)   ̴ 13 × 13 µm@ hν = 30 eV

 

SOURCE

The source is a pure permanent magnet APPLE II helical undulator. It was designed by the ID group of ALBA and produced by Kyma S.r.l. . It is capable of delivering linearly polarized light (vertical and horizontal), as well as circularly-polarized light (left- or right-handed), in the whole photon energy range of the beamline. 

ParameterValue
Period 125 mm
Number of periods 16
Minimum gap

13.0 mm

Max Bx [T]

Linear H: 0.0000

Linear V:1.0594

Circular: 0.7734

Max By [T]

Linear H: 13.3095

Linear V: 0.0000

Circular: 9.0296

 

OPTICS LAYOUT

The first optical element inside the optical hutch is a flat mirror (M1). The following element is in the experimental hall and it is the monochromator (green square), which includes three switchable spherical mirrors (SM) and four varied-line-spacing (VLS) plane gratings. Downstream the monochromator there is a plano-elliptic mirror (M3), which focuses the source horizontally at a plane placed 0.5 m upstream the exit slit. The beam is vertically focused by the monochromator mirrors at the exit slit plane. Finally, a Kirkpatrick-Baez (KB) mirror pair (blue square, configuration of plano-elliptic mirrors one vertically deflecting, VFM, and the other horizontally deflecting, HFM) refocuses the beam on the sample.

IM_LOREAOpticsLayout

Optical scheme of the LOREA beamline.

  

ENDSTATION

The end station will be composed by a central radial distribution chamber to which all other vessels are connected, including chambers for: ARPES investigation; in situ UHV deposition and characterization; high pressure deposition (Chemical Vapor Deposition, CVD, and Atomic Layer Deposition, ALD); organic molecule deposition; sample storage; docking of vacuum suitcases; docking of STM; and fast entry load lock. An upgrade of the system, including a spin detector and an STM, is planned.

IM_LOREAEndstation

Endstation layout.