Associate Director Matthew Miller promoted

He is promoted to the rank of fellow in the American Society of Mechanical Engineers (ASME)

CHESS congratulates Professor Matthew Miller, the associate director of CHESS and the director of InSitµ@CHESS, for a recent promotion to the rank of fellow in the American Society of Mechanical Engineers (ASME).

The rank of fellow is bestowed on members who “have been responsible for significant engineering achievements” and have been active members for at least ten years. Professor Miller’s work developing new X-ray techniques, primarily at CHESS, and his development of the In-Sitµ center were mentioned prominently in his award citation, highlighting their importance to the mechanical engineering community. “Professor Matthew P. Miller is an international leader in the development and engineering application of high energy x-rays to probe the micro-structure of materials under live loads. Prof. Miller founded and directs InSitµ@CHESS (Integrated Simulation and x-ray Interrogation Tools and Training for µmechanics at CHESS).

Where did those electrons go?

Decades-old mystery solved

The concept of “valence” – the ability of a particular atom to combine with other atoms by exchanging electrons – is one of the cornerstones of modern chemistry and solid-state physics. Valence controls crucial properties of molecules and materials, including their bonding, crystal structure, and electronic and magnetic properties.

Four decades ago, a class of materials called “mixed valence” compounds was discovered. Many of these compounds contain elements near the bottom of the periodic table, so-called “rare-earth” elements, whose valence was discovered to vary with changes in temperature in some cases. Materials comprising these elements can display unusual properties, such as exotic superconductivity and unusual magnetism.

But there’s been an unsolved mystery associated with mixed valence compounds: When the valence state of an element in these compounds changes with increased temperature, the number of electrons associated with that element decreases, as well. But just where do those electrons go?

>Read more on the CHESS website

Image: Illustration of ytterbium (Yb) atoms in YbAl3, where electrons transform from localized states (bubbles surrounding the yellow orbitals) to itinerant states (hopping amongst orbitals), as a function of temperature.


RAW Power!

MacCHESS software brings synchrotron-level data processing to the laptop and home laboratory

Since its introduction by Søren Skou (Nielsen) in 2010, the BioXTAS RAW software has been a familiar interface to the many biomedical scientists collecting data at CHESS beamlines in recent years. From the start, RAW was designed specifically with novice users in mind: when scientists arrive at the beamline, they need something fast and easy to learn in the very limited time available … often late at night.

The program was literally designed by looking over the shoulders of beamline users as they collected data. But rather than simply create an automated data processing pipeline, we opted to give people the power to fully process data on their own computers at home, if they choose. This allows them to use the same software at other beamlines and even on their own home X-ray sources: from initial raw data reduction to final publication. Indeed, with over 4000 downloads in 2017, RAW is now the primary processing software at several other beamlines and lab source facilities worldwide.

>Read More

Picture: Richard Gillilan, Jesse Hopkins, and Soren Skou at the annual Amrican Crystallographic Association meeting where they conducted a tutorial in the BioXTAS RAW software.

Focusing on microbeam: Initial installment of CRLs at CHESS

A great challenge is to direct x-rays into a very small, very clean footprint while maintaining high photon flux.

A great challenge at many x-ray beamlines is to direct x-rays into a very small, very clean footprint while maintaining high photon flux. This is especially important when illuminating very small samples, as in protein microcrystallography where crystals can be on the order of a micron across and diffract weakly compared to larger crystals. Any excess scatter in these conditions will contribute unwanted noise and decrease the overall signal-to-noise ratio – an important measure of data quality. Consider an experiment where you first must take the water from a firehose and somehow get a water thread thinner than a human hair without any mist! That is akin to the scale of creating x-ray microbeam at CHESS.

One solution would be to simply block the x-rays down to the size desired, but this has the unfortunate side effect of throwing away vast numbers of photons. Fortunately, x-rays can be manipulated similar to visual light and therefore focused using optical components such as mirrors and lenses. Recently, an optical design of interest at CHESS incorporates the focusing power of x-ray compound refractive lenses (CRLs) to create an x-ray beam on the order of microns across – effectively, a microbeam.

>Read More

Picture: The assembled and aligned lenses in their casing. Two brass pinholes bookend the stack of lenses, which all sit in a v-groove designed to be sub-micrometer in accuracy.

The state of CHESS-U beamlines

The beamline upgrade portion of the CHESS-U project is moving ahead at full steam.

Scientific needs have been identified. A suitable layout for the experimental floor has been devised. The work breakdown structure (WBS) has been created and System Managers have been assigned. Two large contracts have been awarded and designs are being vetted. We are almost ready to cut metal.

One year has passed since I was asked to be Project Manager for the beamline half of what has become the CHESS-U project. With fits and starts, working around an intense operations schedule, CHESS staff have accomplished a remarkable amount of work so far in preparation for the largest upgrade we have tackled in CHESS history. Summer 2016 started off with a series of science workshops to facilitate creating a science case for the future of CHESS. They also provided guidance for fleshing out upgrade concepts leading up to an External Conceptual Design review in December. With those concepts blessed, technical specs and designs proceeded in earnest. Critical paths were identified, leading to contracts being awarded for sector front ends and hutches to local company Advanced Design Consulting (ADC).