Skip to main content

Lab Book 2014_05_13 Leak Detector Work and Checks of Rotating Frames and Special Relativity

Lab Book 2014_05_13     Hamilton Carter               

Summary
After fixing the crusty battery cable in the car this morning, I got to do a little bit of work around the lab before the end of the day.  We met and discussed the special relativity work today as well.  Fermi-Walker transport makes sense as just being the acceleration normal to the tangential velocity that changes the direction of the tangential velocity.

The hose between the auxiliary roughing pump and the leak detector was attached.  The auxiliary pump is used to rough out the volum to be leak detected before using a valve on the leak detector to attach the built in diffusion pump to the volume to attain a much higher vacuum, (in the range of 10E-8 Torrs).

The added hose used the fittings I built a few weeks ago to attach the system.  There’s an intermediate piece that contains an O-ring that fits between the KF fitting on the hose and the pump assembly.
New KF fitting I constructed

O-ring fitting that fits between the two KF fittings

Break-away fitting clamp

Half of clamp enclosing hose and pump fitting with interfacing O-ring

Completely clamped connection

The liquid nitrogen Dewar still had liquid in it, but apparently the lid flange was leaking.  This was not allowing any pressure to build up and so the liquid nitrogen was not exiting the Dewar.  The liquid level was 26 inches as of about 4:30 PM today.  I’ll measure again tomorrow.  We may leak detect a very large liquid helium Dewar along with the glass and fiberglass Dewars.  I need to locate heating tape so we can heat up the Dewar to re-activate the active carbon filter inside.

I worked more on QFT in rotating frames as well.  My original calculations showing that gamma doesn’t participate in the transverse Lorentz force may be incorrect.  I’ve started a new derivation approaching the problem from the direction of four force.  The check and a few notes on Fermi-Walker transport can have been added to the paper positing that the number operator might not be valid for circular motion.


Current pdf version of relativistic work










Comments

Popular posts from this blog

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems, there seem to be fewer explanations of the procedure for deriving the conversion, so here goes!

What do we actually want?

To convert the Cartesian nabla



to the nabla for another coordinate system, say… cylindrical coordinates.



What we’ll need:

1. The Cartesian Nabla:



2. A set of equations relating the Cartesian coordinates to cylindrical coordinates:



3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system:



How to do it:

Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables.

The chain rule can be used to convert a differential operator in terms of one variable into a series of differential operators in terms of othe…

Lost Phone

We were incredibly lucky to have both been in university settings when our kids were born.  When No. 1 arrived, we were both still grad students.  Not long after No. 2 arrived, (about 10 days to be exact), mom-person defended her dissertation and gained the appellation prependage Dr. 

While there are lots of perks attendant to grad school, not the least of them phenomenal health insurance, that’s not the one that’s come to mind for me just now.  The one I’m most grateful for at the moment with respect to our kids was the opportunities for sheer independence.  Most days, we’d meet for lunch on the quad of whatever university we were hanging out at at the time, (physics research requires a bit of travel), to eat lunch.  During those lunches, the kids could crawl, toddle, or jog off into the distance.  There were no roads, and therefore no cars.  And, I realize now with a certain wistful bliss I had no knowledge of at the time, there were also very few people at hand that new what a baby…

Lab Book 2014_07_10 More NaI Characterization

Summary: Much more plunking around with the NaI detector and sources today.  A Pb shield was built to eliminate cosmic ray muons as well as potassium 40 radiation from the concreted building.  The spectra are much cleaner, but still don't have the count rates or distinctive peaks that are expected.
New to the experiment?  Scroll to the bottom to see background and get caught up.
Lab Book Threshold for the QVT is currently set at -1.49 volts.  Remember to divide this by 100 to get the actual threshold voltage. A new spectrum recording the lines of all three sources, Cs 137, Co 60, and Sr 90, was started at approximately 10:55. Took data for about an hour.
Started the Cs 137 only spectrum at about 11:55 AM

Here’s the no-source background from yesterday
In comparison, here’s the 3 source spectrum from this morning.

The three source spectrum shows peak structure not exhibited by the background alone. I forgot to take scope pictures of the Cs137 run. I do however, have the printout, and…