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XAS
BRIGHT Beamlines

Medium Energy X-ray Absorption Spectroscopy Beamline (MEX-1 and MEX-2)

Beamline updates

September 2021 

September has been a quiet month on site. Melbourne is in lockdown due to a COVID outbreak, construction sites are temporarily shut down, and permits are required to carry out essential work on site.

The MEX team has been using this time to test equipment, order parts, get through paperwork, and prepare for the coming months post-lockdown when we'll be starting commissioning without beam. 

 

Previous Beamline Updates

August 2021

August saw the completion of the MEX photon delivery system installation – the main components of the beamline. MEX engineers and scientists will now spend a few weeks tuning and programming beamline parts to prepare for commissioning in the coming months.

MEX hutch A

Looking upstream (towards the storage ring) along the PDS in Hutch A.

 

MEX hutch A 4

MEX PDS view from the door of Hutch A. Upstream (towards the storage ring) is to the left of the image, and downstream (towards the end stations) is to the right.

 

In late August, the MEX scientists presented at a joint two-day workshop with the X-ray Absorption Spectroscopy (XAS) beamline team. On the first day of the workshop, MEX scientists discussed the beamline rationale, commissioning timeline, technical setup, and equipment capabilities. We also heard from the XAS team and Synchrotron users about XAS experiments and the exciting science that will be enabled by MEX. The slides from this workshop are available at the event website here.

July 2021

What a difference a month makes! July began with empty MEX hutches, and is ending with Hutch A packed to the rafters. Three engineers from Axilon – a German company that builds accelerator and X-ray instrumentation – have been busy installing MEX’s photon delivery system (PDS).

The PDS is the first part of the beamline the X-rays see when they come out from the storage ring tunnel and into the hutches. It tunes the size, shape, focus, and energy of the X-ray beam. The main components of the PDS include mirrors, double crystal monochromators, and slits.

MEX update august 2021

Engineers preparing one of the MEX1 mirrors to be enclosed and put under vacuum.

mex update august 2021

 Lowering the MEX1 mirror cover over the mirror using the hutch crane. 

MEX scientists tested out the crystal spectrometer on the XAS Beamline earlier this month (for a refresher on the crystal spectrometer, check out the March and May 2021 updates). The goal was to obtain good spectral data from a sample containing mercury, testing out each of the crystals in the five crystal mounts on the spectrometer.

The experiment was a great success! You can see the first high energy resolution fluorescence detection (HERFD) spectra (red) obtained from the crystal spectrometer compared to conventional X-ray absorption near edge structure (XANES) spectra (blue) in the image below.  

mex update august 2021

Graph comparing spectra obtained using the crystal spectrometer (HERFD; red) and from conventional XANES (blue). 

June 2021

In early June, Rick Ford, an engineer from Instrument Design Technology Ltd, arrived to assemble MEX’s double crystal monochromators (DCMs).

Rick travels around the world assembling and installing synchrotron beamline components (job goals!), including part of the XAS beamline here at the Australian Synchrotron.

The DCMs consist of two sets of two crystals (Si(111) for MEX1; Si(111) and InSb(111) for MEX 2). The crystals are aligned so that the beam hits the first crystal set, is diffracted to the second crystal set, and from there is diffracted to continue along the beamline. The angle of the crystals relative to the beam defines the energy of the beam, so the DCM is one of the most important components of the beamline.

MEX progress June 2021

The DCM in a pop-up clean room for assembly.

MEX DCM Si(111) crystals.

MEX1 DCM configuration showing the second crystal set installed. The lower surface of the crystals is covered with a wipe for protection.

MEX1 with both crystal sets installed. The crystals are just below the centre of the image, and are covered with white lab wipes.

The final product: MEX1 and MEX2 DCMs completed and with their covers on.

In other June news, building of the MEX user cabin is now complete. The user cabin sits directly next to the hutches and is where users and Beamline Scientists will be located while operating the beamline. Check out the last stages of construction in the video below.

Video showing the construction of the MEX user cabins.

May 2021

May has been a busy month here at MEX. The final components of our hutches arrived and construction on them has now been completed. See the video below for the construction process following on from the March update.

 

These hutches are now ready for utilities to be installed. Construction works will now focus on the user cabins, which our future users will soon(ish) become very familiar with as this is where they'll work when they come to use the Beamlines.

 

Our Controls Engineers have had a fruitful month working on our crystal spectrometer (check out the March update for more info). They now have all all the motors for the spectrometer working together. You can be mesmerised by the fruits of their labour in the image below.

via GIPHY

Image showing each of the stages of the MEX crystal spectrometer moving together.

 

Now you'd better go stock up on popcorn because with the first components of the Beamline being assembled in the coming weeks, the June update is going to be a big one! 

 

April 2021

This month we celebrated the arrival of our newest MEX Beamline Scientist, Dr Krystina Lamb. With Krystina's arrival, we now have a full MEX team!

We thought this would be a good time to introduce you to the gang working to get MEX operational for our future user community.

The MEX build is managed by our Project Manager and fearless leader, Mr Mohamed Elrabiey. Mohamed ensures the project is progressing on time and on budget, and coordinates parts and people coming in from all over the world (in COVID times!).

MEX's Mechanical Engineer, Mr Ben Pocock, leads the designing and sourcing of Beamline parts. He is responsible for all the mechanical components of the Beamline. 

Mr Ben Baldwinson is our Senior Controls Engineer, and works with fellow Controls Engineers Mr Danny Wong and Mr Ross Hogan to ensure the Beamline components operate as they should. The Controls engineers bridge the gap between the Beamline hardware and software. 

Mr Dion Curic is MEX's Mechanical Technician. He makes, designs, and assembles Beamline components. 

Our Scientific Computing team, Senior Scientific Software Engineer Dr Letizia Sammut and Scientific Software Engineer Mr Alex Palma, design and implement all the user-focused Beamline software components. Mr Andrew Starritt is constructing the Graphical User Interfaces for Synchrotron scientists to commission and operate the Beamline. 

Finally, meet the MEX Beamline Science team! Once the Beamline is operating, the Science team will be running the Beamline, training and assisting users, and troubleshooting any Beamline issues. For now, the scientists are ordering Beamline components and directing Beamline specifications. This team is led by Dr Chris Glover, and consists of Beamline Scientists Dr Jeremy Wykes, Dr Simon James, Dr Emily Finch, and Dr Krystina Lamb. We look forward to meeting you when MEX opens to users in 2022!

MEX beamline team

Photograph of some of the MEX team in front of the newly constructed MEX hutches. Left to right: Krystina Lamb, Simon James, Chris Glover, Ben Pocock, Emily Finch, Jeremy Wykes, Ross Hogan.  

 

March 2021

Building has begun! 

Our trusty builders have commenced assembly of the MEX Beamline hutches. The hutches walls are blue to differentiate from the white user cabins, and contain lead to shield radiation. 

Once the hutches are built, the mechanical and electrical components will be installed.

Behind the scenes, parts are trickling in from around the world ready for installation in the hutches. One of our most exciting recent arrivals is the crystal spectrometer, which will produce high energy resolution spectra to allow us to discern detail that would otherwise be obscured. This piece of kit is an exciting new technology for our Synchrotron users!

Spectrometer MEX

The main optical components for the Beamline are currently undergoing factory acceptance testing before being shipped in the coming days and weeks.

Stay tuned for monthly updates as parts continue to arrive and activity ramps up!

Capability Summary and Techniques

 

The MEX-1 and MEX-2 beamline utilises one bend magnet as the source and will operate independently and has been designed to be experimentally flexible, extending and complementing the suite of the X-ray spectroscopy techniques already available at the Australian Synchrotron.

At MEX, the instrumental capabilities are focused on:

  • Spanning the soft and hard X-ray energy regimes (1.7 – 13.6 keV).
  • Minimising radiation damage (by using relatively larger beam sizes and lower flux densities).
  • Easily tunable beam sizes (from µm to mm).
  • Routine, high-quality X-ray Absorption Spectroscopy (XANES and EXAFS) of bulk specimens.
  • Routine use of non-ambient sample environments.
  • High energy resolution fluorescence detection (HERFD) X-ray absorption spectroscopy.
  • High quality micro-spectroscopy (2.0 – 13.6 keV).

MEX-1

This beamline will offer monochromatic X-rays (from a Si<111> double crystal monochromator) at one of three endstations, with variable beam sizes at a fixed height from the floor. The different MEX-1 endstations will not be able to operate simultaneously.

Multiple modes of operation:

  1. Bulk XAS (EXAFS and XANES) 3.5 – 13.6 keV in transmission and fluorescence. Sample in helium gas environment at ambient or variable temperatures (10-300K).
  2. Bulk HERFD-XAS (EXAFS and XANES) 3.5 – 13.6 keV, via a 5-crystal 0.5m Johann-type spectrometer. Sample environment: variable temperature (10 – 300 K), helium gas atmosphere and/or vacuum (continuous gas flow cryostat).
  3. Range of non-ambient sample environments, including electrochemical cell, flow cell, pressure cell or furnace. Please get in contact with the Beamline Team to discuss the details.
  4. Scanning X-ray fluorescence microscopy, optimised for microspectroscopy (EXAFS and XANES) 2.1 – 13.6 keV, harmonic content < 10-4. Microfocus will be adjustable between 2 and > 10 μm. Sample in helium gas atmosphere, variable temperature (80 – 500 K) via liquid nitrogen cooled He(g) cryostream.

MEX-2

This branch line will offer low energy monochromatic X-rays – from either InSb<111> or Si<111> – double crystal monochromators at a fixed position and with a maximum beam size of 2 x 5 mm2. Slits can be used to reduce the beam profile on the sample. Sample environment: variable temperature (~10 – 500 K), helium gas atmosphere and/or vacuum.

Multiple modes of operation:

  1. Bulk XAS (EXAFS and XANES) 1.7 – 3.5 keV in transmission, drain current and fluorescence.
  2. Bulk HERFD-XAS (EXAFS and XANES) 1.7 – 3.5 keV via single crystal, dispersive refocusing Rowland circle geometry-type spectrometer.

Scientific Applications

The MEX beamlines have been designed to offer a range of capabilities for undertaking XAS measurements across a wide range of scientific applications, with a particular emphasis on in situ and in operando experiments. Collecting high-quality data while minimising the dose delivered to the sample is expected to be another strength. MEX will also bring the new and powerful tool for chemical research, HERFD-XAS, to the Australian Synchrotron, opening new avenues for material characterisation.

Human Health and Biology 
  • Studies of the chemistry and function of metalloproteins in biology. As much as one-half of all biological catalysts require a metal for activity, and iron-containing metalloproteins like haemoglobin perform vital functions like storing and transporting oxygen throughout the body.  Understanding the molecular-scale structure, function and mechanism of such proteins is essential in determining how metal biology contributes to health and disease.
  • Oxidative stress in cells and tissues contributes to diseases of ageing like dementia and can be quantified by determining the chemical ratio of sulfur-containing thiols and thiolates. The distribution and abundance of these molecules within cells are also crucial to a myriad of biological processes, including tumorigenesis.
  • The chemical state and distribution of phosphorus is key to understanding cellular the structure and well-being of bone and teeth.
  • K-edge XAS is an ideal tool to study the binding and transport of potassium and calcium ions by coronavirus viroporins, information useful for screening drug candidates during pre-clinical development.
Food, agriculture, and plant biology

In soils and minerals, silicates, phosphates, sulfur and chloride ions are common, and X-ray absorption spectroscopy of these ions can reveal the chemical environment in which they are present. When combined with the XAS on metals present in the same milieu, superior definition of the chemical speciation and spatial distributions will be possible compared to relying on a metal K-edge XAS alone. Such information is invaluable for the study of soil salination, the efficacy of fertilisers in agriculture, plant growth and micro-nutrient transport, as well as the distribution and bioavailability of essential micro-nutrients in food.

Advanced materials, catalysis, and chemistry

The target energy range of the MEX beamlines will open up numerous avenues of research into advanced materials.

  • Silicon is the backbone of the electronics industry and more exotic semiconductors such as indium phosphide are emerging for specialist applications. The ability to characterise these materials post modification allows the details of atomic structures that directly impact performance and suitability for applications in electronic components to be observed.
  • Many emerging materials technologies include amorphous and micro-crystalline materials, nano-particulates and composites.  The MEX beamlines can investigate the chemistry and local atomic structure of these materials that often ill-suited for characterisation via diffraction-based techniques. 
  • Silicon has multiple commercial and a better understanding of the structure/function relationship of amorphous and crystalline phases of silicon, and silicon oxide is relevant to several industrial and engineering process but critical to the development more efficient silicon-based photovoltaics.
Environmental studies

Studies of numerous pollutants in the environment and their decomposition are readily studies using the MEX beamlines.  Examples include:

  • The redox status and speciation of sulfur-containing compounds in the environment;
  • The distribution and speciation of inorganic and organophosphate pollutants and their breakdown;
  • The speciation of organochlorine pollutants and their breakdown to inorganic chlorides. Chlorine K-edge XAS for example, can be used to study the fate of NaCl in coal to determine temperature thresholds for the formation of highly undesirable organochlorine by-products of coal combustion.
Earth Science and minerals formation

By making use of non-ambient sample environments, experiments designed to reveal the speciation of complexes under hydrothermal conditions or lead to a better understanding of geochemical process like the transport and deposition of precious metals through the earth’s crust can be undertaken. Examples include:

  • Studies of acid sulfate soils.  Sulfur K-edge XAS can be used to identify reactive intermediates in reduced sulfur sediments to characterise biotic versus abiotic reaction chemistry, as well as to understand the chemistry in different acid sulfate soil environments.
  • Numerous precious metals are present in ore bodies as sulfide minerals.  The MEX beamlines can be used to study mineral formation processes, as well as methods to optimise their extraction.
  • The redox state of Fe and S in glasses and melt inclusions. The oxygen fugacity of magmas can be inferred from Fe redox state. The solubility of sulfur in magmas, and hence magmatic ore deposit formation, is highly dependent on the speciation of sulfur. The MEX1 microprobe will permit microspectroscopic mapping at 2-10 microns spatial resolution.
Cultural Heritage, Archaeology, and Arts

Many of the pigments used in artworks and prevalent in archaeological artefacts contain metals as well as sulfur-containing, chloride and phosphate ions. 

  • MEX measurements of artwork and cultural heritage artefacts will assist significantly in the identification of pigments, as well as their ageing and weathering processes. 
  • In combined with historical records, characterisation of such pigments and dyes are essential in establishing provenance, and also provides vital information to support curatorial practices and restoration projects.

When MEX studies are combined with the dating of samples, information such as ancient cultural practices and trade associations lead to important understandings of many aspects of the development of civilisation and the preservation of cultural heritage worldwide

Technical Information and Specifications

Beamline Layout

Beamline layout 1 - MEX 1 2

Beamline layout 2 - MEX 1 2

Beamline layout 3 - MEX 1 2

Technical Specifications

View MEX 1 and 2 Technical Specifications

Number of Beamlines

MEX-1: monochromatic, 2.1 – 13.6 keV

MEX-2: monochromatic 1.7 – 3.5 keV

Number of Endstations

MEX-1: 3

MEX-2: 1

Source

 

Bending magnet (BM12-1)

 

 

 

Optics

MEX-1

 

 

Mirror 1 (M1) –

Vertical collimation

 

- Fixed, flat Si substrate

- Cylindrically bent

- Bounce up (4.75 mrad)

- Exchangeable C, Ni and Rh stripes

 

Double crystal monochromators

 (DCM)

- Si<111>, ?E/E ≈ 1.4 ×10-4

- Crystal azimuth (?) 0° and 30°

- Vertical bounce

 

Mirror 2 (M2) –

Vertical and horizontal focussing

- Cylindrical + flat Si substrate

- Elliptically bent

- Bounce down (4.75 mrad)

- Exchangeable C and Rh stripes

 

 

 

 

MEX-2

 

 

Front end mirror (M1) –

Vertical collimation

- Fixed sagittal cylinder

- Horizontal bounce (15 mrad)

- Cr stripe

 

Mirror 2 (M2) –

Horizontal collimating

- Fixed cylinder

- Horizontal bounce (15 mrad)

- Cr stripe

 

Double crystal monochromators

 (DCM)

- Si<111>, ?E/E ≈ 1.4 ×10-4

- InSb<111>, ?E/E ≈ 3 ×10-4

- Crystal azimuth (?) 0°

- Vertical bounce

 

 

 

Endstations

MEX -1

 

 

XAFS Station

- EXAFS/XANES

- 3.5 – 13.6 keV

- Transmission and florescence (4 el. Si SDD)

- Sample temperature 10 – 300 K (in He(g))

- HERFD-XAS:

> 0.5 m Johann-type crystal analyser

> 5x spherically bent crystals. See here for further information on crystal cuts and accessible emission lines​​​​​​

 

- Non-ambient sample environments

- Beam size 0.15 – 0.5 x 1.8 – 7 mm2

- Flux 3 x 1011 ph-1 sec-1

 

Microprobe station

- µEXAFS/µXANES

- 2.1 – 13.6 keV

- 3 el. Si SDD

- 2-moment KB mirror system

- Exchangeable C and Rh stripes

- Beam size: 2 – >10 µm

- Flux 108 ph-1 sec-1 µm2

- Sample in He(g)

- Sample temperature 80 – 500 K

- Scan range < 80 × 80 mm

 

MEX-2

(“Low energy station”)

EXAFS/XANES

- 1.7 – 3.5 keV

- Transmission, drain current and florescence

(4 el. Si SDD)

- HERFD-XAS:

>Dispersive refocusing Rowland geometry

>Single cylindrically bent, Si<111> Johann analyser

- Beam size 0.1 – 2 x 0.1 – 5 mm2

- Flux:

Si<111> 5 x 1010 ph-1 sec-1

InSb<111> 1 x 1011 ph-1 sec-1

- Sample in He(g) or vacuum

- Sample temperature 10 – 300 K

Beamline Status

View beamline status

Date

Status

2017 July

Project started

2018 January

Investment Case (IC) approved and endorsed by ANSTO

2018 June

Conceptual Design Report

2019 March

PDS Contract Placed (Axilon, Germany)

2019 July

Technical Design Report

2019 August

DCM (X2) Contract Placed (IDT, UK).

2020 February

Crystal Spectrometer Order Placed (Huber, Germany)

2021 Q1 - Q2

Arrival of Crystal Spectrometer and DCMs on site

2021 Q1 - Q2

Installation of Hutches and User cabin

2021 Q2 - Q3

Installation of PDS and DCMs

2021 Q3 - Q4

Installation of endstations

2022 Q1

Hot commissioning begins, includes expert users

2022 Q3

First User Experiments; Beamline fully commissioned over the next 12 months

Staff

Mr Mohamed Elrabiey – Project Manager

Dr Chris Glover - Lead Scientist

Dr Jeremy Wykes - Beamline Scientist

Dr Emily Finch - Beamline Scientist

Dr Simon James - Beamline Scientist

Dr Krystina Lamb - Beamline Scientist

Mr Ben Pocock – Mechanical Engineer

Mr Ben Baldwinson – Senior Controls Engineer

Dr Letizia Sammut – Senior Scientific Software Engineer

Mr Alex Palma - Scientific Software Engineer

 Mr Dion Curic - Mechanical Technician

Beamline Advisory Panel

Professor Peter Lay (Chair) – University of Sydney

Prof. Dr Serena DeBeer - Max Planck Institute for Chemical Energy Conversion

Associate Professor Peter Kopittke - The University of Queensland

Dr Rosalie Hocking - Swinburne University of Technology

Dr Mark Hackett - Curtin University

Dr Andrew Berry – Australian National University

Contact

as-mex@ansto.gov.au