17 January 2008
Residence time of lab samples
Posted by Jessica Ball
I was lucky enough to live near the lab, although it was several hours’ drive away from my campus. The first week I worked there was during my winter break, which was fine; almost a month off between semesters is enough to make anyone eager to get out of the house. The second week, however, was during classes, and I had to make special arrangements with several professors outside of the geology department to miss classes so I could go home and work at the lab. On completing the mineral separations and having prepared the samples for irradiation, I was assured by the scientist I was working with that I would have data from the samples in time to include it in my senior honors thesis. (This was early February, and my thesis was due late in April.)
Fast forward again to April. After having heard little from the lab (and with my advisor having had as little luck as I did in getting in touch with the person I’d worked with), I finally succeeded in getting through on the phone – and was told that not only had my samples not been run, they had never been sent off for irradiation. There was some explanation about the cost of reactor time and wanting to include as many samples in the shipment as possible, but it wasn’t clear why I had been told that I would have data in time for my thesis when it wasn’t really going to happen. I was very upset, but after a while I calmed down and came to agree with my advisor on the point that it would be one less thing to write up in an already long thesis, not to mention that we were going to write a more comprehensive paper later. (The dating was originally a major part of my thesis proposal, but as I ended up branching out into structural and geochemical aspects later on, it wasn’t totally devestating not to have it.)
And now the current state of affairs: Advisor and I are in the process of writing a paper on multiple volcanic deposits in the area where I did my field work, and are of course eager to include Ar dates in it, seeing as I didn’t get to them in my thesis, and we’re trying to correlate the deposits with other regional volcanics. And what’s the status of our samples?
Still not run (although they have been irradiated). This time the excuse is a somewhat legitimate one (the equipment has been broken and the head of the lab was unaware of it, having been on vacation for a month), but it’s still extremely frustrating – not to mention that I have to wonder why the samples were sitting around all summer and fall of last year. So, I now have irradiated samples but no data, thus stalling another paper. My advisor had also planned on me taking the time to learn how to reduce the data, but it’s going to become more and more difficult to find the time for that, since I’m working full time and will have to start visiting prospective graduate schools soon.
My question for everyone else is, is this a normal thing? I understand that a non-academic lab might not run on the same schedule as an undergraduate trying to write a thesis, but it’s now been almost a year to the day since I started working on those samples, and I find it hard to believe that this kind of turn-around time is acceptable in a research situation. I invested a considerable amount of time and effort into this and even missed classes so I could complete the sample preparations and leave enough time to have them analyzed for my thesis.
I somehow feel I’ve been gypped, but I don’t know what other peoples’ experiences have been with this kind of situation.
My glib response would be: “Don’t worry. The samples stop aging once you collect them.”I can’t really say how common this is, but having worked in a lab like this one I do know that scheduling is often interrupted by machine downtime. Then there are grant deadlines that change the priority of samples, too. Unfortunately I’d guess that your sample didn’t have the kind of priority status that would have kept it at the front of the line. While it’s certainly not the experience you’d like an aspiring geologist to have, I can’t say it surprises me, either. It sure isn’t the sort of customer experience you come to expect from the business world, but then lab analyses of this type are definately not subject to the same sorts of free market pressures you’re used to in the business world.
One question, did you pay the lab to run the samples or is this a freebie?If you paid to have the samples run, then I think you have every right to complain (constant phone calls if necessary) to get your samples completed. If however, this is a freebie, I am not surprised your samples got pushed to the bottom of the pile – and keep getting pushed to the bottom of the pile.I work in a user facility lab and money makes the world go round (or at least keeps us in business). Those researchers that send us money get first priority while those that are getting machine time or technician help have to work around paying customers. A year is pretty ridiculous though. My advice is to keep after them or they will keep forgetting that you need your samples analyzed. Good luck!
Ron – Ha! You’re right, I should remember that. Mel – It is a freebie. However, this is a government lab (you can probably guess which agency) and they’re not exactly hurting for money. Not to mention that while I was there, I helped prepare some samples that weren’t mine, and there didn’t seem to be much else on the roster.Fortunately, I live pretty close to the lab and I can keep nagging on the phone and in person.
Actually, there is a problem with waiting too long for Ar samples. Irradiation creates a bunch of new radioactive isotopes, and you have a limited amount of time to be able to measure them with decent precision. (Thermochronic would probably be able to tell you more; I gave up dating rocks ten years ago. They just got old, you know?)I’ve only dated samples (a) when I was in grad school and was one of the people keeping things running, and (b) when I visited, did my own dating, and dated some other samples while I was at it (in the same lab where I was a grad student). And the second time, I got help from some of the then-current grad students, too.I probably still owe them beer for that help.
Kim,I think the half-life of 39Ar is about 260 years, so hopefully that isn’t the rate-limiting step in this case.As for the freebie, is that what your adviser said or what the lab guy said? When I was a PhD student, I called and hassled a collaborator for results after a year or so, at which point she came back with, “Well, your adviser hasn’t paid me yet.”Finally, I agree with Mel- the more people pay, the faster it gets done. But a year isn’t that long. It isn’t that short, but it isn’t that long, either. Think geologically. 😉
Hmm…that’s a good point, I should check to make sure there aren’t money issues. I think we did pay for a portion of the reactor time, and I did the prep work for free, so it wouldn’t be a total financial drain on the lab, but it’s worth checking.And you’re right, Chuck – geologically speaking, a year is nothing! In fact, it’s positively warp speed!
Chuck – I can’t remember which Ar isotope was the issue. I think it may have been 37Ar? It was used to correct for one of the possible interferences.Thermochronic would know. He’s been in an argon lab more recently than I have. All I remember is being told that I needed to date somebody’s samples before mine, because their data wouldn’t be any good if the samples weren’t dated.