The Cell

Over the course of the past two years, I’ve used OpenSCAD to design a gas/vacuum cell that can support a pressed silica nanoparticle pellet in front of a variety of spectroscopy systems. The core of the cell was 3D printed in aluminum by Shapeways, with some subsequent facing on our lathe to get good seals with the O-rings. This first version is designed to fit into our fluorimeter.

The Cell I

After using the first cell for a year, I realized I also wanted to be able to attach it to a fiber-optic-based spectrometer. Here, you can see the second cell attached to our Schlenk line.

The Cell II

Schlenk Line in Development

This is my Schlenk line; there are many like it, but this one is mine. The double-manifold design allows my students and me to expose samples to either vacuum or inert gas (argon, in this case.) Every line has little tweaks and customizations made by the scientist using it, and is thus inevitably a work-in-progress. This particular line very much needs a full-time vacuum gauge as its next addition.

Schlenk Line in Development

3D Printing Materials

In addition to photography, I’ve been exploring 3D printing in the past few years. I’ve found that it’s a great route to making small objects to support my science work. In this case, I was developing a holder to support a 12.7 mm pressed solid sample pellet inside the space normally occupied by a 10-cm pathlength liquid-handling cuvette. The result is this odd rectangular shape that unlocks to hold the “too wide” pellet diagonally—thanks, square root of two!

In these forms, I was working with a variety of materials, including glass-reinforced nylon, lost-wax-cast brass, and a bronze/steel powder combination.

3D Printing Materials

Glass Bridges of Johnson Hall

I often show what I think of as the front of Johnson Hall of Science, but inspection of this image (particularly the top of the brick wing on the left) shows that the building’s name, and thus its front, are on this side. The dramatic glass structures extending between and out from the wings lend credence to the idea.

Glass Bridges of Johnson Hall


The hours I spend in the physics and chemistry labs of St. Lawrence University make me a bit inured to the optical shenanigans occurring when we take Raman spectra of the materials my students synthesize. Still, the effect is pretty fantastic. The grainy pattern of the laser on surfaces around lab is fantastic, but the fluorescence ink on the post-it note in the foreground fluorescing aggressively is pretty cool, too.

Homebuilt Raman Apparatus

That violet-blue light in the background of the shot above is the 405 nm laser we use to initiate photochemical processes. The beam is poorly detected by the camera’s sensor, but the slightest hint of it is visible in the upper third of the image below.

405 nm

Cartesian Grid of Building 66

The utilitarian, earthquake-resistant architecture of Berkeley Lab amid the verdant hills of the East Bay seems like a science-fictional setting—a location that can’t possible exist—in contrast to San Francisco in the distance.

Cartesian Grid of Building 66

Winter On Campus

St. Lawrence University’s campus is quiet for the moment; athletes have returned early from break but pretty much everyone else is still on winter vacation. The snow adds an extra layer of dampening.

Winter Trees Outside Johnson Hall

When they return,  the school will once again take on its weird ski lodge vibe.

Student Life Under Freeze

End of 2018 (Recalling the Lab)

Professionally, 2018 was a good year: my sabbatical work was published in the Journal of Physical Chemistry C. That came from a long time writing and a long time in this lab.

Testing Facility

Berkeley Lab’s Frei Group was kind enough to share their space with me, and I could not have done that work without this high vacuum line. I’ve always loved the way understanding the components of a system can take a complicated image like this one and break it into understandable parts. This image, in particular, gets less odd after the realization that this is two lines, mounted back-to-back, in the same Unistrut frame.

High Vacuum Line

Spectroscopy Lab

Approaching the summer solstice, the start of fall-semester classes and their attendant labs seems far away, but a new class of St. Lawrence first-year students will be here before I know it.

Spectroscopy Lab I

This was one of the light sources students were interrogating: a sodium lamp, like the ones used in street lights (at least in the twentieth century—LED street lamps are becoming increasingly dominant now.)

Spectroscopy Lab II

532 nm

In St. Lawrence’s Raman spectroscopy and microscopy lab, the most potent laser illumination source comes from a neodymium-doped yttrium aluminum garnet. This is a pretty ubiquitous laser source, but I happen to like it because it also demonstrates the value of nonlinear optics: though this laser is emitting light at 1064 nanometers (in the infrared), a suitable doubling crystal can combine two of those 1064 photons together to make a shiny new 532 nm photon.

532 nm