Meanwhile, in the lab... Dewar Moves and Leaky Vacuum Pumps

Lab Book 2014_06_20 Hamilton Carter

New to the lab book? Scroll to the bottom for background and a summary of the experiment.

Pulling the Dewar from the Table

The spray Styrofoam was shaved off the Dewar this morning revealing that the Dewar had originally been installed on a piece of regular Styrofoam and the spray coating was added later

The plan is to peel away as much of the spray foam as is practicable, and then do a two person lift of the Dewar out of the table. The Dewar will be immediately placed in a padded box.

The Dewar was successfully removed! Next, I’ll remove the shelf and put the magnet in place. There’s one cooling tube that was knocked off the magnet as it turns out, so that will have to be fixed.

Vacuum Pump Down!

The leak detector vacuum pump appears to be broken. The reading on it is a much worse vacuum than from the auxiliary one on the lower shelf of the cart


Leak Detector Pump	Auxiliary Pump

The pump was tested using a thermocouple gauge system shown below. The actual vacuum detector has a blue label is attached to the OCF brass flange. The flange isn’t visible as it is enclosed in the larger black plastic clamp.

The detector cable plugs into a readout box:

The flange was attached directly to the mechanical roughing pump that was being tested by first detaching the hose between the mechanical and the diffusion pump at the diffusion pump end and then inserting the assemblage shown attached to the gauge above into the hose as shown below

I’m wondering how much work it would take to put our thermocouple vacuum meter on an Arduino data capture system, hence the digital voltmeter in the second picture to check the voltages that are available and should be somehow related to the vacuum reading on the meter.

Background

Hirsch's theory of hole superconductivity proposes a new BCS-compatible model of Cooper pair formation when superconducting materials phase transition from their normal to their superconducting state[1]. One of the experimentally verifiable predictions of his theory is that when a superconductor rapidly transitions, (quenches), back to its normal state, it will emit x-rays, (colloquially referred to here as H-rays because it's Hirsch's theory).

A superconductor can be rapidly transitioned back to its normal state by placing it in a strong magnetic field. My experiment will look for H-rays emitted by both a Pb and a YBCO superconductor when it is quenched by a strong magnetic field.

This series of articles chronicles both the experimental lab work and the theory work that’s going into completing the experiment.

The lab book entries in this series detail the preparation and execution of this experiment… mostly. I also have a few theory projects involving special relativity and quantum field theory. Occasionally, they appear in these pages.

Call for Input

If you have any ideas, questions, or comments, they're very welcome!

References

1. Hirsch, J. E., “Pair production and ionizing radiation from superconductors”, http://arxiv.org/abs/cond-mat/0508529

The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1. While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero. This is typically explained in the following way. While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare. That doesn't stop us from looking for them though! Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2]. Cabrera was utilizing a loop type of magnetic monopole detector. Its operation is in...

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

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics 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 ...

More Cowbell! Record Production using Google Forms and Charts

First, the what : This article shows how to embed a new Google Form into any web page. To demonstrate ths, a chart and form that allow blog readers to control the recording levels of each instrument in Blue Oyster Cult's "(Don't Fear) The Reaper" is used. HTML code from the Google version of the form included on this page is shown and the parts that need to be modified are highlighted. Next, the why : Google recently released an e-mail form feature that allows users of Google Documents to create an e-mail a form that automatically places each user's input into an associated spreadsheet. As it turns out, with a little bit of work, the forms that are created by Google Docs can be embedded into any web page. Now, The Goods: Click on the instrument you want turned up, click the submit button and then refresh the page. Through the magic of Google Forms as soon as you click on submit and refresh this web page, the data chart will update immediately. Turn up the:...

Copasetic Flow

Search This Blog