The Crystals of Mystery
I recently inherited some items from my grandfather.
That’s not quite right. I was recently given some memorabilia from my grandfather’s career at NASA that had probably been sitting in a drawer for decades because I showed interest. I’d know that he’d worked for NASA for most of his career and had some vague idea that he’d done something with growing artificial crystals, but I didn’t know any specifics and for that matter neither did anyone else when I finally got around to asking. I had a distant relationship with my dad’s parents when they were alive. We always lived several states away, and at most I’d see them every couple of years growing up, and well, I just never thought to ask.
It’s an oddball collection of stuff.
-A commemorative paperweight, approximately the size of my palm. Inscription reads: Space Systems Center Dedication, missile and space systems a division of Douglas Aircraft Company Inc, November 14, 1963. The back has the astrological symbols arranged around the sun. Several similar examples can be found for sale on ebay and this article talks a little bit about the dedication.
–H.R. 2337 Bill for the Space Industrialization Act of 1979 for the US House of Representatives. It looks this Bill was introduced but never went anywhere. Why did my grandfather save a print copy? WHY?
-A technical paper titled “Commercial Materials Processing in Space” Authored by my grandfather. Full text is here.
Here’s the transcription of the above photo:
1. Crystal contaminated with rhodium from crucible http://education.jlab.org/itselemental/ele045.html information about rhodium. By-product of platinum/palladium mining, mostly used as alloy compound.
2. Transparent crystal grown from platinum crucible. Contains many gaseous inclusions resulting from high growth rate and insufficient stirring.
3. Attempt to grow out dislocation starting from seed having 10^4 dislocations/cm^2. High thermal gradient resulted in severe deformation and generation of new grains.
4. Section of crystal grown on high thermal gradient.
5. Thermal gradient was somewhat diminished by doping crystal with Fe^3+. THe result was fewer dislocations.
6. Section of Fe^3+ doped crystal.
7. Photomicrograph (photograph of a microscopic image)(10X) of (010) plane etched with KOH. Crystal grown in low thermal gradient.
8. Photograph (10X) produced by anomalous x-ray transmission through same section as NO. 7. The dislocation density is 10^4/cm^2 at the top and decreases to 10^2/cm^2 at the bottom of the crystal. These are probably the lowest dislocation density oxide crystals ever grown by the Czochralksi method.
So ok, what do I do with all of this? Were these objects were saved because they have some sort of significance or were saved because they were stuck in a drawer and forgotten about? It could honestly go either way.
I ended up emailing the NASA history department a general query, expecting nothing, and they got back to me extremely quickly with the press release for my grandfather’s appointment to his position of Director of the office of technology implementation. One of the main things I knew about my grandfather was that he “liked technology” which seems to have understated the case just a hair. But really want I wanted to know about were the box of crystal samples. Asking around got me a lot of “Huh this looks cool and interesting and not my field” which, fair enough. Artificial crystal growth research from the 60s is pretty specific.
My friend who’s a chemical engineer pointed out that at least one of goals of the above was to reduce the dislocation in the crystal structures (why hello there, term I’d never heard before). Annnnd this is the point where being mildly curious about my grandfather’s career turned into attempting to teach myself a whole new vocabulary. I know what dislocation means when referring to a joint, but a crystal structure? And what does it matter and why they were trying to reduce it? My friend was able to explain the first question but not second (see link, because I’m not sure that my understanding of ‘make the structure smoother’ is accurate except in the most general way)
I found a clue in the term “Czochralksi Method” in the last description above. This seems to be a preliminary step in making semi-conductors (link included because I can’t be the only one who’s heard these terms her entire life without really considering what, exactly, they meant)
But, ok, all the above information makes me think these samples should have something to do with electricity, with electronics. Except they’re all talking about silicon, and what I’m looking at is not a box of silicon samples, but…actually I don’t know. The materials of the crucibles are mentioned, but the crystals are just “crystals”. Except that, no, I’d just managed to miss the notation on the front of the box reading “Evolution of low dislocation density ZnWO4″, aka Zinc Tungsten Oxygen 4.
I’m usually optimistic about my ability to understand anything as long as I find definitions for all the technical jargon, but that ended up being a bit of a problem. I tried, I really did, to make sense of some academic papers where I had to google at least a word per sentence but as it turns out my strength of will and mental fortitude have limits. It doesn’t help that it turns out there have been MANY papers written about the properties of ZnWO4 and I’m totally unequipped to judge which one is best. It turns out it’s kind of tricky to figure out if a paper answers the main question I have from the abstracts, which is what do you DO with the stuff? I think this one might start to answer the question of what do you do with this material, but I’m honestly not certain. At least there are some graphs and it’s not behind a paywall? But in any case I still don’t know what the goal was of the research my grandfather was doing (Supervising? Signing off on?).
So yeah, the major takeaway from this story is that science communicators writing for a general audience are the best most helpful people. Seriously, the language issue is a big problem when it comes to understanding new concepts and people who can explain complicated things using simple everyday language are a gift and should be CHERISHED, and trying to slug through all these academic papers about a topic that I have no background in at all made me really, really appreciate that.
Bonus: This thing! It counts something! Probably something electrical! And it was saved in my grandparents’ basement in its original box for decades!