Advantages of CAMD
CAMD offers a number of synchrotron based techniques: X-ray based: XAS, XRF, electron yield, XRD, SAXS, Biomed, tomography, X-ray phase contrast imaging, cell irradiation, macromolecular crystallography, MAD phasing - VUV based: XPS, soft-XAS, Photoionization studies, ARUPS, LEED, Omicron 150 mm – other: White Light - FTIR – diagnostic tools (using lasers, pinhole camera) - read more about each technique here
These techniques in combination with synchrotron radiation have the following benefits compared to lab source-based experiments:
• Nearly all of the elements of the periodic table can be investigated.
• Intense X-ray/VUV beam (of at least 1 order of magnitude stronger than a lab source)
allowing superior statistics/speed.
• better energy / wavelength resolution because of the continuous spectrum
• better spatial precision of the incident/diffracted beam (synchrotrons produce a
parallel beam)
• choice of mode: monochromatic (angle-scanning) or white radiation.
• one can use several techniques (XAS, NEXAFS, Tomography, IR, etc.) at the same time
CAMD can offer more beamtime than other sources!
The services offered at CAMD that come with the time spent for measurements:
a) Beamtime can be applied for without a long proposal process and scheduled on a
short-term basis.
b) Scheduled beamtime can be flexible.
c) Beamtime is available for one day to up to weeks (depending on the sample system
and experiment).
d) Direct support from a CAMD staff member with long term experience in the technique
you need to use, and staff can conduct the measurements to ensure successful data
collection.
e) One-on-one teaching of synchrotron techniques by a CAMD staff member.
f) One-on-one teaching by a CAMD staff member regarding the data analysis – and in
some cases the CAMD staff member can perform the complete data analysis for the user.
g) Help with any issues or questions before and after the beamtime.
h) Students can learn in depth the details of a certain technique guided by a CAMD
staff member.
i) Versatility: new experimental setups (including gas phase, in-situ, size of samples)
can be integrated into a beamline.
j) Use multiple techniques offered at CAMD at the same time!
k) Special range of XAS energies from 200 eV to 1.2 keV and 1.7 keV to 25 keV.
Why pay when I can get beamtime free at National Light Sources
CAMD vs. National light sources (such as APS, NLSL II, SSRL, CHESS, ALS) What are the hidden costs of remote user facilities?
• First you must write a winning proposal – competition for beamtime can be significant
• Beamtime can be limited – if your experiment doesn't work you have to wait for the
next beamtime cycle
• Hidden costs for travel include transportation, housing, meals
• Data analysis may have a learning curve – you may have to rely on the remote lab
beamline scientist for expert advice
Using CAMD for projects has these advantages:
a) Getting beamtime is easier! – There is just not enough beamtime at available at
national facilities to serve all interested users. However, there is availability
at CAMD.
b) Do not have to write a proposal way in advance - beamtime is available within a
short time and you can have more beamtime within a year repeatedly.
c) Users can have beamtime for a week or more to be able to get the experiment right.
You can bring new samples from your lab every day.
d) Users can install their own experimental end station tailored to their measurement
needs.
e) Students can learn all the different aspects of the method used.
f) Students can learn and practice with their equipment at CAMD to use at a national
light source to get the experiment right – instead of trying to get a new beamtime
assignment after failure at the national lab.
g) For LSU students: no travel, no housing, no food cost.
h) Users can use all (!) the techniques available at CAMD without writing a new proposal.
i) At CAMD it is quite easy to analyze any sample system with all the different techniques
available, even just testing out if a technique is worthwhile.
As an example: For a project analyzing Pb in plants, XAS experiments at different Pb absorption edges (Pb L3 (13 keV, M5 (2.5 keV, M3 3.0 keV, M1 3.8 keV) as well as P, S, Cl K edges (2-3 keV) were performed to understand which Pb absorption edge and the organic counterpart is giving more information about the chemical structure of Pb in the plants. In the soft X-ray range, the O K-edge was investigated as well. In addition, tomography experiments were performed on pieces of plant roots to determine the location of most of the Pb in the plant root, supporting the information gathered by the XAS experiments (published here https://pubs.acs.org/doi/10.1021/es302408m)
“Would it be better to set up a lab source?”
In an article about laboratory-scale X-ray absorption spectroscopy, Bes et al., 2018
(https://doi.org/10.1016/j.jnucmat.2018.04.034) discussed that “the development of alternatives is mandatory to compensate the currently
lacking beamtime.”
Laboratory-scale X-ray absorption spectroscopy (XAS) or Small angle scattering (SAXS)
experiments have been available for some extent. The hidden cost is that it is mandatory
to hire trained personnel to facilitate the experiments – At CAMD we have the personnel
to support and supervise the experiments and teach students. Furthermore, lab-based
XAS or SAXS experiments are not comparable to a synchrotron facility like CAMD.