Information for beamtime

Pre-Run information

Welcome new or potential user, or continuing user considering a new type of experiment. SSRL BL6-2C is a hard X-ray, full-field microscope. It is used for mesoscale analysis of many types of samples including energy materials, mineralized tissue, environmental samples, etc. Because of its relatively wide field of view (FOV) of ~30 microns combined with high resolution (~30 nm) it can image a wide sample area, and determine morphological and chemical heterogeneities crucial to materials performance, ex situ or during operation.

Note that the beam line is highly oversubscribed, and hence beam time is hard to come by. Some of the advice below is intended to maximize your efficiency so that you can collect high quality data and make the most of the beam time.

Manuals

Before arriving:  Sample holder base CAD

At the beamline:  Data acquisition quickstart  TXM troubleshooting  XM Flex Manual

Analyzing data:  Downloading data  Data analysis checklist Links to TXM Wizard How To Videos

TXM Wizard Help TXM Wizard data analysis overview  TXM XANES Wizard Help

Topics:

Beam line capabilities

  • Resolution 30-50 nm depending on zone plate, magnifying objective, energy, 2D or 3D

  • Energy Range 4.5-13 keV absorption contrast

  • FOV 15-30 microns

    • larger FOV with mosaic imaging but sample thickness should not greatly exceed depth of focus DOF (depends on energy and zone plate)

  • Tomography, XANES imaging, XRF detection

  • In situ imaging – temperature, pressure, gas delivery, mass spec, batteries, etc

Your experiment

  • Feasibility: Please contact beam line staff (see TXM web site for contact information) to discuss feasibility of your experiment and focus on portions of your scientific questions that the TXM can best answer.

  • Staff will ask about other characterization that you have done before considering TXM (e.g. bench testing of batteries and catalysts, testing of in situ cells and setup, and XANES on a bulk XAS beam line and/or other X-ray methods before TXM XANES imaging).

  • Staff may recommend brief screening time to determine whether samples have good absorption contrast, appropriate thickness, and/or sufficient signal to noise for XANES imaging. In some cases this screening will require an initial Letter of Intent.

  • Sample environments (pressure, temperature, gases etc.)

    • Staff may be able to work with you to design an experiment or discuss custom

      sample environments

    • Be sure these are well tested before beam time, and compatible with microscope sample stage, etc.

    • Do you need your custom sample holder to fit? Sample holder base CAD

  • Safety: Cover any safety issues with SSRL staff.

    • Create any necessary standard operating procedures (SOP’s) and have them approved by SSRL safety officers. 

  • Sample preperation (size, FIB, etc.)

    • Thickness of the attenuating portion should be less than the DOF. For example in battery pouch cells the polypropylene pouch and binder, etc. do not significantly attenuate hard X-rays. However, the thickness of the attenuating metals is crucial. It is also important not to have attenuating portions that are out of focus, because this will affect quantification of X-ray attenuating, which is crucial for tomography or for XANES imaging.

      • Slices several hundred nm to several microns thick are good for mosaic 2D imaging. Because this is a transmission method, the acceptable thickness is dependent on how many features will be viewed through each pixel.

    • Tomography samples should ideally be mounted on a post or within a capillary for full access to 180 degrees for image collection. If fluorescence data will be acquired the post should be non-metallic. For many materials a cylinder prepared by focused ion beam (FIB) of about 20 microns in diameter is ideal.

  •  Need for a team/ night coverage so that imaging continues 24 hours per day during beam time.

Obtaining beam time

  • Detailed information on SSRL user access that you must read is given at

    http://www-ssrl.slac.stanford.edu/content/user-resources/welcome-ssrl-us...

    Some highlights are listed below:

    • If you are a first-time user (and for any new members of your team), register as a user at the SSRL User portal

    • Submit proposals through this site. Due dates for standard X-ray proposals are September 1, December 1 and June 1. They will go through peer review and be assigned a rating. Highest rated proposals will be scheduled with priority, and lower rate ones may not be competitive for beam time.

    • Once you have received the proposal rating you must submit a beam time request for each beam line you want to use. If you are not sure how much is reasonable, please consult with staff.

    • You can conduct safety training online before arrival.

    • Once you are assigned beam time you will need to make a support request. You will enter team members that will come on site, and make any requests for laboratory space and/or glove boxes for sample prep, and enter safety information about the samples you will bring.

Planning for beam time

  • Even if your safety training is current, please contact the user office before you arrive to make sure your badge is current.

  • New users: contact Ellie Fazli to get a computer account and authorization to use SPEC

  • Safety concerns

    • Be sure that any safety issues/SOP’s have been covered/approved with SSRL staff

    • Sample environments (pressure, temperature, gases etc.) – be sure these are well tested before beam time, and compatible with microscope sample stage, etc.

    • Any electrical equipment that you bring will need to be checked out by SSRL. Please allow at least one day before you plan to use it for this. This service is only available during normal business hours (not nights or weekends).

  • Sample preparation – be sure samples are an appropriate size, and ready to go.

    • Bring redundant samples and backups in case some do not work out.

  • Team required – plan on a minimum of two people to run samples and concurrently analyze data. If you are running in situ you may need more. If you are running with toxic gases or anything particularly hazardous, a trained team member must be at the beam line at all times to monitor the experiment.

  • Hardware: Besides samples and any equipment for sample environments, bring an external hard drive (≥1 TB) for backup data transfer

  • What to expect during beam time

    • Beam line staff will align beam and microscope at start of your run, for all energies you will need.

    • Beam line staff will train you on sample mounting, data collection and processing, etc. so that you and your team can continue with data collection and analysis

    • You are expected to run efficiently and, to the greatest extent possible, use the beam whenever it is available. Hence the need for careful sample preparation, pre- characterization, testing of setups, and adequate team for running.

Data Collection and Analysis

  • We have streamlined our setup for efficient data collection, access and processing.

  • Data Handling: During data acquisition, files are automatically transferred to a network drive under your user name (or b_txmuser), which you will be able to access from off site. (Instructions here) You may also want to bring an external hard drive (1 TB or larger) to make a second copy of the data. All user data is deleted from the acquisition PC within days. The user is responsible for data copying/backup.

  • Data Collection: The new GUI-based XM Flex software developed in collaboration with Zeiss makes it possible to image with a combination of energy scans, tomography, mosaic imaging, signal-averaged data collection, and reference collection for single or multiple samples and/or locations within a sample. Camera dynamic range has been extended by adding images on the camera. You can download the XM Flex Manual here.

  • Data Analysis: TXM Wizard Software created in-house at SSRL includes preliminary data processing (reference averaging and correction, averaging of multiple reference- corrected sample exposures), monitoring of data collection, and analysis of imaging data sets including tomography, XANES imaging and 3D XANES imaging. A new GPU reconstruction algorithm speeds up tomographic reconstruction by a factor of about 102. To get started use this TXM Wizard data analysis overview. There are also a bunch of How To videos on YouTube for common analysis on TXM Wizard.

  • Hardware and software requirements for data analysis at your home institution

    • System requirements for TXM Wizard analysis software

      • Windows 64, multi-core CPU, GPU for tomo reconstruction

      • Download TXM Wizard

      • Help files: TXM Wizard HelpTXM XANES Wizard Help

      • You will also need to install the appropriate MCR Installer for this Matlab executable file (more info at Source Forge)

    • For tomography data: You will need AvizoTM or Dragonfly ORS or another 3D visualization capability for visualization of reconstructed tomography

Publication of Scientific Results

Please inform SSRL staff of all your publications from SSRL beam time. Publication within a reasonable period is expected for continued access to beam lines.