Re: Meanwhile, back in the lab...


Gregory L. Hansen wrote:
> In our last episode, a neutron guide at NIST broke from radiation
damage,
> sending a chunk of glass through the magnesium window and destroying
my
> monochrometer.
>
> The guide had been fixed weeks ago, the monochrometer recently
replaced
> and the shielding moved back in, allowing me access to that liquid
> nitrogen dewar that had been blocked in for a month. I've adjusted
the
> rotation and tilt angles of the monochrometer to maximize flux, and
now
> I'm trying to take a beam picture to see what it looks like.
>
> We have a wonderful imaging plate that's loaded with lithium-6;
expose it
> directly to the beam and read it out in the BAS-2000. So I built a
jig to
> hold it, brought Health Physics in to check the setup, gave it a 30
second
> exposure, and brought it to Building 245 to read it. And found out
the
> BAS-2000 had been broken for some time, and there's no plans to fix
or
> replace it. So I tried reading it on the BAS-1800II, but that only
> accepts magnetic plates, and this one isn't magnetic.
>
> Plan B was to use dysprosium foil, which activates in neutrons and
emits
> betas with a half life of a few hours. Except our dysprosium foil is

> small, and I wanted a larger picture. And big peices of dysprosium
are
> another one of those things you don't just buy at Staples.
>
> Plan C is to activate a copper plate which we happened to have laying

> around. That has a smaller capture cross-section and the isotope of
> interest has a half-life of 13 hours, which translates to a whopping
> exposure to get something useful. The reactor was down Monday and
> Tuesday.
>
> So I was ready to expose it today, after the talk by our guest
speaker.
> But Health Physics had some concerns about the amount of radioactive
> material to be transported, and where it will be kept. And then they

> disappeared for a while. Turns out they were trying to figure out
how
> many prompt gammas would be created. I don't think there'll be any,
I got
> some ENDF data that seemed to say no prompt gammas until 100 keV, and
my
> neutrons are little meV. And with hours to expose, wait out some
> short-lived products, and transfer to an imaging plate, it just got
late.
> So we'll try it again tomorrow.
>
> And science marches on. Sort of.
>
> Nothing unusual, just another day in the lab.
>

Not everyone would be as even tempered.

A colleague of mine (now deceased - died of cancer at a very young age)
was told by his thesis adviser that, no, he couldn't trade data-logging
shifts to go pick up his mother from OHare airport, even though she was
flying in from India just to see him. Adit didn't say anything but
stormed out of the trailers that we used as a control room. Then there
was a big noise. When we went out to see what caused it, Adit was
standing in the gravel parking lot holding onto the doorknob. The
doorknob was still attached to the door. The door was not, however,
still attached to the trailer.

I returned quietly to my place at the console and went back to work.

PD

.

Relevant Pages

  • Re: Meanwhile, back in the lab...
    ... > In our last episode, a neutron guide at NIST broke from radiation damage, ... > Plan B was to use dysprosium foil, which activates in neutrons and emits ... > neutrons are little meV. ... > short-lived products, and transfer to an imaging plate, it just got late. ...
    (sci.physics)
  • Re: Meanwhile, back in the lab...
    ... >In our last episode, a neutron guide at NIST broke from radiation damage, ... >The guide had been fixed weeks ago, the monochrometer recently replaced ... >neutrons are little meV. ... >short-lived products, and transfer to an imaging plate, it just got late. ...
    (sci.physics)
  • Re: Meanwhile, back in the lab...
    ... a neutron guide at NIST broke from radiation ... | We have a wonderful imaging plate that's loaded with lithium-6; ... Except our dysprosium foil is ... | neutrons are little meV. ...
    (sci.physics)
  • Meanwhile, back in the lab...
    ... In our last episode, a neutron guide at NIST broke from radiation damage, ... The guide had been fixed weeks ago, the monochrometer recently replaced ... We have a wonderful imaging plate that's loaded with lithium-6; ... Plan B was to use dysprosium foil, which activates in neutrons and emits ...
    (sci.physics)