Elettra
BL 08.2 - BACH

The BACH beamline (Beamline for Advanced diCHroism) is an undulator beamline of the Istituto Officina dei Materiali-Consiglio Nazionale delle Ricerche, which operates at Elettra, in close collaboration with Elettra-Sincrotrone Trieste S.C.p.A.. The beamline offers a multi-spectroscopy approach for the investigation of the electronic, chemical, structural, magnetic and dynamical properties of solid surfaces, interfaces, thin films and solid samples in the UV-soft x-ray photon energy range (44-1650 eV) with selectable light polarization (linear horizontal and vertical, circular), high resolving power (20000-6000) and time resolution (70 psec). Each UHV endstation has a UHV connected preparation chamber for sample growth and surface preparations (sputtering, annealing, evaporators for organics and metals, LEED, mass analyser, leak valves for gas exposures...) and a quick UHV connected sample transfer load lock. In the load lock, exposures up to 100 torr of selected gas and sample heating up to 1000 K can be performed.

The experimental setup of the BRANCHcan also combine Laser and Synchrotron Radiation (SR) in order to study the dynamics of the photo-induced excited states of electronic and magnetic systems with pump-probe time-resolved XAS. Elettra Synchrotron radiation source provide radiation pulse widths sufficiently short to investigate dynamic processes in the time between 70 ps up to 0.5 μs. Typically, optical excitation of the sample is done by laser pulses (synchronized to either hybrid or multi bunch SR pulses), and probing is performed by time-delayed synchrotron radiation pulses.

An hemispherical analyser with vertical entrance slit and 2D detector offers the possibility to perform polarisation dependent soft-x ray ARPES and VUV ARPES in the full range of the beamline (44-1650 eV) on in situ prepared samples.

Sample holders for UHV compatible fluorescence yield XAS in liquid environment are available upon preliminary request.

Recently an in-operando soft-x-ray XAS set up has been implemented at BACH to bridge the “pressure gap” between UHV and ambient pressure, based on the confinement of liquids in a cell with a window separating the fluid from the UHV. One of the end-stations has been dedicated to experiments based on electron transfer processes at the solid/liquid interfaces and during photocatalytic or electrochemical reactions. Suitable cells to perform soft x-ray spectroscopy in the presence of liquids were developed: static cells to study the solid/liquid interface of catalysts in the presence of an electrolyte both in total electron yield (TEY) and fluorescence yield (TFY), and an electrochemical flow cell which allows to carry out in situ cyclic voltammetry, electrodeposition on a working electrode (WE) and to study chemical reactions in-operando conditions and under selected applied voltages.

Endstations and experimental techniques

ENDSTATION A:XPS/UPS,VUV and soft x-ray ARPES,RESPES, RES-ARPES, CIS, Photoelectron Diffraction, fast XPS (ms), XAS (TEY,PEY,TFY,PFY),XLD, in remanence XMCD, XES, Time resolved laser pump-probe XAS (ps) 50-100 K to 800 K + UHV Preparation Chamber

ENDSTATION B: in-operando soft-x-ray XAS set up (at the solid/liquid interfaces and during photocatalytic or electrochemical reactions)

BRANCHLINE C: available for user endstations

 

 

Beamline Energy Resolution
0.006 [eV] @ 44 [eV]
0.35 [eV] @ 1650 [eV]
0.025 [eV] @ 500 [eV]
Beamline Resolving Power
6.6 * 103 [E/deltaE] @ 870 [eV]
1.5 * 104 [E/deltaE] @ 530 [eV]
1.2 * 104 [E/deltaE] @ 400 [eV]
1.2 * 104 [E/deltaE] @ 90 [eV]
1.6 * 104 [E/deltaE] @ 50 [eV]
5.5 * 103 [E/deltaE] @ 1650 [eV]
Beamline Energy Range
44 - 1650 [eV]
Max Flux On Sample
5 * 1012 [ph/s] @ 125 [eV]
2 * 1011 [ph/s] @ 1000 [eV]
6 * 1011 [ph/s] @ 1500 [eV]
Spot Size On Sample Hor
250 - 350 [um]
Spot Size On Sample Vert
10 - 350 [um]
25 - 350 [um]
Divergence Hor
0.5 [urad]
Divergence Vert
0.1 [urad]
Angle Of Incidence Light On Sample Value
5 - 90 [degrees]
Photon Sources

High Energy Undulator

Type
Undulator
Available Polarization
Linear horizontal, Linear vertical, Elliptical, Circular
Variable Polarization
Yes
Source Divergence Sigma
X = 0.5 [urad], Y = 0.1 [urad]
Source Size Sigma
X = 240 [um], Y = 50 [um]
Energy Range
175 - 1650 [eV]
Number Of Periods
44
Period
48.36 [mm]

Low Energy Undulator

Type
Undulator
Available Polarization
Linear horizontal, Linear vertical, Elliptical, Circular
Variable Polarization
Yes
Source Divergence Sigma
X = 0.5 [urad], Y = 0.1 [urad]
Source Size Sigma
X = 240 [um], Y = 50 [um]
Energy Range
22 - 600 [eV]
Total Power
200 [W]
Number Of Periods
27
Period
77.36 [mm]
Monochromators

Monochromator BACH

Energy Range
44 - 1650 [eV]
Type
VASGM
Resolving Power
12000 [E/deltaE] @ 90 [eV]
6600 [E/deltaE] @ 867 [eV]
Number Of Gratings
4
Grating Type
spherical gratings
Pre-focusing Mirror Type
plane mirror
Endstations or Setup

Cryomagnet 6T XMCD

Description
Currently NOT AVAILABLE to users. If interested for a long-term project please contact us.
XAS (X-ray Absorption Spectroscopy) in total eletron yield (drain current) and total fluorescence yield (photodiode), XMCD (X-ray Magnetic Circular Dichroism) and X(M)LD [X-ray (Magnetic) Linear Dichroism] under high magnetic fields (superconducting magnet) and at variable temperature 1.8 K-340 K. Optical ports for laser in-laser out. A surface preparation and sample growth facility is in preparation. UHV environment.
Spectrometer
Total electron yield drain current
-6.5 to +6.5 Tesla superconducting magnet
1.8 K-340 K cryostat
Base Pressure
5 * 10-10 [mbar]

Sample

Sample Type
Crystal, Amorphous

Manipulator or Sample stage

Multispectroscopy XPS/ARPES/XAS/XES

Description
PES (Photoelectron Spectroscopy), automatic ResPES (Resonant Photoemission Spectroscopy), VUV and soft x ray ARPES (Angle Resolved Photoemission Spectroscopy), Temperature-programmed PES, XAS (X-ray Absorption Spectroscopy) in total electron yield (both drain current and a channeltron are available), partial electron yield (using the electron analyzer), total fluorescence yield (MCP), partial fluorescence yield (using the fluorescence grating spectrometer), XMCD (X-ray Magnetic Circular Dichroism) in remanence, X(M)LD [X-ray (Magnetic) Linear Dichroism] in remanence, SXES (Soft X-ray Emission Spectroscopy) and inelastic scattering spectroscopy RXES (Resonant X-ray Emission Spectroscopy), Low Energy Electron diffraction (LEED), Surface preparation and sample growth facilities. Variable sample temperature 120 K - 1300 K (sample
temperature down to 50 K possible with LHe cooling). Optical ports for laser in-laser out. UHV environment. Currently used also for pump-probe time resolved XAS in total fluorescence yield. Sample cell for fluoresce yield measurements in liquid environment.
Microscopes
Not available at the beamline. However an ex situ microscope facilities are available upon request.
Spectrometer
1) Scienta3000 hemispherical electron energy analyzer for angle-resolved photoemission spectroscopy (energy resolution better that 3 meV and angular resolution better than 0.5°, quick acquisition mode to perform fast photoemission with 300 msec total acquisition time per spectrum. The same instrument can be used to acquire core levels, work function, VUV to soft x ray ARPES, automatic energy dependent ARPES, Partial Yield XAS (secondary or Auger electrons), together with the drain current from the sample (TEY), automatic resonant photoemission and temperature-programmed photoemission

2) ComIXS fluorescence spectrometer with grating for x-ray emission spectroscopy and partial fluorescence yield spectroscopy and medium resolution (~1 eV at 800 eV)- (ask if operative)

3) Channeltron and MCP (ask if available/installed)

4) Keithleys (428 and 6430) for drain current x-ray absorption spectroscopy

5) Ultrafast MCP for total fluorescence yield time-resolved x-ray absorption spectroscopy
Base Pressure
2 * 10-10 [mbar]
Detectors Available
fast MCP
Drain Current
Endstation Operative
Yes

Sample

Sample Type
Crystal, Amorphous
Other Sample Type
liquid (after contacting beamline scientist about feasibility)
Mounting Type
clamps, epoxy glue, silver paint, carbon tape...
Required Sample Size
X = 5000 [um], Y = 2000 [um], Z = 1000 [um]

Techniques usage

Absorption / NEXAFS
TEY (drain current),PEY (secondary electrons measured by the Scienta analyser) , AEY (Auger electrons measured by the Scienta analyser), TFY (photon out measured by the MCP) ,PFY (energy resolved photon out by the ComIXS-currently not available to users)
Absorption / Time-resolved studies
Optical excitation of the sample is done by laser pulses (synchronized to either hybrid or multi bunch SR pulses), and probing is performed by time-delayed synchrotron radiation pulses.
Absorption / XMCD
In Remanenece after in situ magnetization with a permanent magnet of 0.5-1T or a variable magnetic field from 0 to 1 kGauss
Emission or Reflection / X-ray fluorescence (XRF)
ComiX spectromenter
http://www.elettra.trieste.it/lightsources/elettra/elettra-beamlines/bach/bach-endstations/page-8.html?showall=
Photoelectron emission / Angular Resolved PES
VUV and SOFT-X RAY ARPES from 44eV to 1650 eV.
Energy dependent ARPES with automatic control of the energy in the sequence
Energy resolution better that 3 meV and angular resolution better than 0.5°, quick acquisition mode to perform fast photoemission with 300 msec total acquisition time per spectrum
http://www.elettra.trieste.it/lightsources/elettra/elettra-beamlines/bach/scienta3000.html
Photoelectron emission / Photoelectron diffraction
Energy dependent PhD with automatic control of the energy in the sequence or Polar angle scans
Photoelectron emission / UPS
Shallow core levels and angle resolved valence band.
Energy dependent measurements with automatic control of the energy in the sequence
Work function measurements.
Photoelectron emission / XPS
Core levels.
Resonant photoemission or energy dependent measurements with automatic control of the energy in the sequence.
Temperature-programmed XPS.
Quick acquisition mode to perform fast photoemission with 300 msec total acquisition time per spectrum
Scattering / Inelastic scattering
Medium-resolution soft x-ray RIXS. Currently not available to users.

Manipulator or Sample stage

Description
In the Main chamber , the sample manipulator is mounted vertically on top of the experimental chamber. In the Main chamber two manipulators are available.
One is a LHe cryostat with 4 degrees of freedom. Its main features are the following:
X-Y (horizontal) travel = ±25 mm; Z (vertical) travel = 200 mm; Angular rotation (polar) = ±180°
Temperature range: 50 K (LHe) or 110 K (LN2)÷1300 K; The minimum temperature depends on the sample holder which is used. For instance using the new VG XL25HC sample holder with PBN and thermoucouple we have reached -4.3 mV on the sample (~100 K).
The temperature range is 250÷1500 K with home-made sample holders, for Si, SiC and Ge.

The other manipulator is a 5-degrees of freedom Omniax manipulator made by VG. This manipulator is currently offline without azimuth. We recommend prospective users to contact the beamline staff if they are interested to use the 5-axis Omniax instead of the Createc on the branch line A. Its main features are the following:
X-Y (horizontal) travel = ±25 mm; Z (vertical) travel = 200 mm; Angular rotation (polar and azimuthal) = ±180°;IMPORTANT NOTICE: Azimuthal rotation is not available at BACH now
Temperature range of the 5-degrees of freedom Omniax: 130÷1000 K (with XL25HC sample holder);
Degrees Of Freedom
4
Translator Stages
3

Sample Environment

Description
UHV conditions. A special cell for fluorescence yield measurements of samples in liquid environment is available.
Pressure (min)
2 * 10-10 [mbar]
Pressure (Max)
1 * 10-6 [mbar]
Temperature
50 - 1300 [K]
Description
For gas exposure at high partial pressure (>10-4 mbar) at temperatures between 300 K and 750 K, a dedicated chamber in vacuum connected to the preparation chamber can be used.
Pressure (min)
5 * 10-11 [mbar]
Pressure (Max)
1 * 10-5 [mbar]
Temperature
300 - 1300 [K]

Sample Holders

Description
suitable for annealing in UHV of silicon, germanium, SiC
Description
This sample holder can be used in combination with a vacuum suitcase. Please contact BACH beamline scientists for details.
Description
PBN annealing up to 1100K. Cooling down to ~130K with LN2.
Large area (~3 cm) to host several samples at the same time.
Transferable from different chambers.
Quick sample transfer from air to UHV
Thermoucouple can be fixed in contact with the sample
It can be used for temperature programmed XPS
Type
heating/cooling
Description
PBN annealing up to 1100K. Cooling down to ~130K with LN2 and ~50K with LHe.
Large area (~3 cm) to host several samples at the same time.
Transferable from different chambers.
Quick sample transfer from air to UHV
Thermocouple can be fixed in contact with the sample
It can be used for temperature programmed XPS

Preparation Chamber

Description
crystal cleaver
Scraper - diamond file / cleaver
Ar+/Ne+ ion sputtering system
1 Leak Valve
2-degree-of-freedom (theta, z) manipulator (continuous annealing up to 700 K, flash up to 1400 K)
Electro Magnet for in-plane magnetization at room temperature from 0 to 1 kGauss
Ports for user evaporators, including a retractable port with gate valve for fast mounting
Pressure gauge and Residual Gas Analyser . p<3x10-10 mbar
Spectrometer
RGA
Base Pressure
2 * 10-10 [mbar]
Endstation Operative
Yes

Sample

Sample Type
Crystal, Amorphous

Time-resolved XAS

Description
The experimental setup of the BRANCH A can also combine Laser and Synchrotron Radiation (SR) in order to study the dynamics of the photo-induced excited states of electronic and magnetic systems with pump-probe time-resolved x-ray absorption spectroscopy. Elettra Synchrotron radiation source provide radiation pulse widths sufficiently short to investigate dynamic processes in the time between 70 ps up to 0.5 μs. Typically, optical excitation of the sample is done by laser pulses (synchronized to either hybrid or multi bunch SR pulses), and probing is performed by time-delayed synchrotron radiation pulses.
Spectrometer
Fluorescence yield ultrafast MCP Hamamatsu, response time =100 ps
Base Pressure
1 * 10-10 [mbar]
Detectors Available
ComIXS Fluorescence Spectrometer
Scienta3000 Electron Analyser
fast MCP
Drain Current

Sample

Sample Type
Crystal, Amorphous, Liquid
Detectors

ComIXS Fluorescence Spectrometer

Type
Fluorescence CCD spectrometer with grating
Pixel Size
X = 12.5 [um], Y = 12.5 [um]
Array Size
X = 2048 [pixel], Y = 2048 [pixel]
Passive or Active (Electronics)
Active

Detection

Detected Particle
Electron

Drain Current

Type
Total Electron Yield Drain Current for NEXAFS
Description
Measurement of the drain current is performed by a 428 Keithley electrometer (from pA to nA)
Passive or Active (Electronics)
Active

Detection

Detected Particle
Electron

fast MCP

Type
Fluorescence yield ultrafast response MCP
Description
Ultrafast MCP-Hamamatsu detector
Time Resolved
Yes
Passive or Active (Electronics)
Active

Detection

Detected Particle
Electron

Scienta3000 Electron Analyser

Type
Electron hemispherical analyser SCIENTA R3000
Time Resolved
Yes
Passive or Active (Electronics)
Active

Detection

Detected Particle
Electron
contacts
Federica Bondino
Elena Magnano
Techniques
Absorption
  • NEXAFS
  • Time-resolved studies
  • XMCD
Emission or Reflection
  • X-ray fluorescence (XRF)
Photoelectron emission
  • Angular Resolved PES
  • Photoelectron diffraction
  • Time-resolved studies
  • UPS
  • XPS
Scattering
  • Inelastic scattering
Disciplines
Earth Sciences & Environment
  • Other - Earth Sciences & Environment
Energy
  • Other - Energy
  • Sustainable energy systems
Material Sciences
  • Knowledge based multifunctional materials
  • Other - Material Sciences
Address
S.S. 14 Km 163.5 Area Science Park Basovizza
control/Data analysis
Control Software Type
  • Labview (for XAS/XMCD/XES/time resolved XAS) and SES for Scienta3000 (XPS)
Data Output Type
  • spectra and images
Data Output Format
  • ascii, txt, pxp, bin, Igor format
Softwares For Data Analysis
  • in-house developed Igor Pro procedures and in-house developed Labview procedures, KolXPD
Equipment That Can Be Brought By The User
Evaporators, hydrogen source, vacuum suitcase, etc. Contact beamline scientists in advance to check for the feasibility.
Users are not allowed bringing any chemical, or any sample, or any instrument at the beamline without any written authorisation of BACH scientists and spp@elettra.eu