Skip to main content

Lab Book 2014_05_24 Electrical and Cooling Work

Summary
Prep work for magnet power supply testing was done today.  A three phase switch box was wired along with an extension cord to reach from the switch box to the power supply.  The input side of the water chilling system was constructed complete with a flow meter.  Only the output side setup remains.

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.  The experiment being performed proposes to look for H-rays emitted by a Pb superconductor when it is quenched by a strong magnetic field.

The lab book entries in this series detail the preparation and execution of this experiment.

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

Checking wire for use with magnet supply

The specs for the wire are as follows:
Product Features
AWG Size:

14
Allowable Ampacity:

15
Amp or Amperage:

15
Cable Type:

Power
Color:

Black
Color Code Chart:

106
Conductor:

Fully Annealed Stranded Bare Copper
Conductor Stranding:

41/30
Construction:

Conductor
Fitting Type:

TB2534K
Insulation:

EPDM
Jacket:

Thermoset CPE
Lbs./M:

208
Length:

Cut To Length
No of Conductors:

4
Nom. Insulation Thickness:

.045 Inches
Nom. O.D.:

.575 Inches
Oil Resistant:

Y
Product Family:

Industrial Cable
Product Type:

Flexible & Portable Cord
Ratings:

UL/CSA
RoHS:

Y
Shielding:

Non-Shielded
Solid/Stranded:

Stranded
Sunlight Resistant:

Y
Temp. Rating:

-40C to 90C
Type:

SOOW
UL:

Y
Voltage:

600V
Water Resistant:

Y
The cable looks like it will just handle the current we want to run through it.

A heavier type P-122 with both a male and female connector is being modified to be fit to the wall mounted switch box. The male connector will be removed and attached to one of the longer E42543 cables. 

The female connector will be left in place and the exposed wires will be attached to the switch box.


The exposed wires on the E42543 cable will be attached to the magnet power supply on the terminal block shown below


The schematic that indicates L1, L2, and L3 are the proper choices is shown below


Checked for shorts between the four leads of the cable and there are none.  The green conductor is attached to the keyed slot of the jack which I’m assuming is the neutral.

I checked the box to make sure all three hot wires were indeed hot, when energized, which they were:


I then turned the breaker off and made sure there was no voltage on the box.


The box was wired to the cord including the green neutral conductor.

Finally, the plug was wired.


Magnet Cooling System
An elbow was placed on the detachable section of the quick-connect for the magnet cooling water so that the water flow meter could be placed in the circuit upright.




References

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



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…