Specifications

NOTE: The information contained in this page is taken from the website: www.wfl.elettra.eu

General Properties
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]
Control And 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

NOTE: the Photon flux is calculated at the maximum resolving power achievable with entrance and exit slit width set to 10 micrometer.
A further grating (SG4) provides 10 times higher flux in the same conditions (but lower resolution).

Since BACH employs two different undulators for different energy ranges, the user must select properly the undulator to work with. Important Note: the two undulators cannot be used simultaneously!!! When one of them is in use (gap below 100 mm) the other must be at the maximum gap (100 mm) and zero phase and zero tapering. If both gaps are below 100 mm a beam dump will occur and all beamlines will loose the beam!

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]

8.1 (High Energy)	From 175 eV-1650 eV	First harmonic:175 eV-730 eV LH: 177 eV-746 eV (gap19-gap50mm) LV: ~367-780 (gap19-gap50mm) CP: ~290-770 (gap19-gap50mm)	2.0 GeV
		First harmonic:247 eV-1030 eV LH: ~247 eV-1074 eV (gap19-gap50mm) LV: ~528-1100 eV (gap19-gap40mm) CP: ~418-1119 eV (gap19-gap50mm)	2.4 GeV
8.2 (Low Energy)	From 35/42 eV to more than 600 eV	First harmonic (highest flux):35* eV-440 eV *The lower Limit is dependent on the polarization and it is actually limited to 35 eV by the monochromator. LH: 16-20 eV (estimated)-140 eV LV: 43 eV-325 eV Circ: 30 eV-270 eV	2.0 GeV
		First harmonic (highest flux):42 eV-620 eV *The lower Limit is dependent on the polarization. LH: 30 eV (estimated)-200 eV LV: 61 eV-470 eV Circ: 44 eV-385 eV	2.4 GeV

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

MONOCHROMATOR: ENERGY RANGES

SG1	44 eV-349 eV (35 eV-42 eV available under special request)	high resolving power: 20000-6000	flux>10¹¹
SG2	158 eV-597 eV	high resolving power: 20000-6000	flux>10¹¹
SG3	491 eV-1650 eV	high resolving power: 15000-5000	flux>10¹¹
SG4	301 eV-1650 eV	medium resolving power: 10000-2000	flux>10¹²

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

Manipulator

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

Manipulator

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

Main XPS Chamber 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]

Preparation chamber Environment

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

Direct current heating sample holder

Description	suitable for annealing in UHV of silicon, germanium, SiC

E-Beam sample holder

Omicron-plate compatibe sample holder

Description	This sample holder can be used in combination with a vacuum suitcase. Please contact BACH beamline scientists for details.

PBN sample holderXL25HC: Heat and Cool block

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

PBN sample holder XL25VH: very hot block

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

Magnetic Fields

Preparation Chamber

Sample
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 Type	Crystal, Amorphous

Time-resolved XAS

Sample
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 Type	Crystal, Amorphous, Liquid

ComIXS Fluorescence Spectrometer

Detection
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
Detected Particle	Electron

Drain Current

Detection
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
Detected Particle	Electron

fast MCP

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

Scienta3000 Electron Analyser

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

SCIENTA OPERATION MODES

1) Transmission or Angle resolved photoemission from 35-44eV to 1650eV with circular, linear horizontal or linear vertical polarization
2) Partial/Auger Electron Yield (CFS)
3) Resonant Photoemission (CIS)
4) Series of measurements (i.e. core levels at different photon energies, series of resonant photoemission, temperature programmed XPS) can be run automatically.

ARPES GEOMETRY

Off-Line Tools and Facilities

Tool/Instrument	Specifications	Location
Hot Plate	50° C-500° C Max Load 5 kg. Max dim. 200x200 mm.	On the table between BACH acquisition room and LASER hutch
Ultrasonic Cleaning Machine		On the table between BACH acquisition room and LASER hutch
Electrical conductive UHV compatible silver epoxy, silver paint and insulating glues		BACH chemical cabinet
UHV compatible Carbon, Kapton and Copper tape; Several sample Clamps		BACH acquisition room
Hot gun
N2 gas line		close to the LASER hutch
Water cooling circuits		close to the LASER hutch
Electric Drill		Black box in the cabinet between BACH acquisition room and LASER hutch
Diamond Files, Sample preparation tools		BACH acquisition room
Pyrometer (reads above 300° C )		Cabinet or Main Chamber area
UHV Thickness monitor	Sycon Instruments STM-100/MF	(it can be mounted on the preparation chamber)
Vacuum sample storage box		Table close to the monochromator
Electromagnet (OFFLINE!)	up to ~2 Tesla
Magnetic coil in the prep chamber	variable field up to 1 kGauss	inside the preparation UHV chamber
Evaporators	http://www.elettra.trieste.it/lightsources/elettra/elettra-beamlines/bach/bach-endstations/page-6.html?showall=
Sample holders (http://www.elettra.trieste.it/lightsources/elettra/elettra-beamlines/bach/bach-endstations/page-5.html?showall=)	2 standard VG XL25VH 1 standard VG XL25HC 3 home-made sample carriers for heating by filament (for radiative sample heating up to 500° C or electron bombardment) (1 currently lended) 1 home-made sample carriers for heating by direct current up to 10 A (e.g. Si, Ge, SiC) 1 sample holder for standard Omicron Plates

Ultima modifica il Martedì, 28 Maggio 2019 17:39