Sandy

Some photos from David of the Farm after Sandy:

Good attachment to the purloins

The wire is still intact, the barbed staples pulled from the post.

Energy Depostion (Co-60)

One of the radiation portal monitor specifications is to be insensitive to gamma rays due to a large natural gamma ray background (medical isotopes, cat litter (potassium), bananas, etc). We are then investigating how much of the energy (from Co-60) is deposited in a film compared to the amount of energy deposited by the charge products of Li-6(n,t)He.  Using geant4 in parallel (shooting a few billion particles, takes about 2 hours on 80 cores) I grabbed the energy deposition for various film thickness, ranging from 15 microns to 1 cm. 

Geant4 Simulations

When compared to the measurements I do fairly well.  The measurements aren't really energy deposition but really pulse height spectra which includes optical photon generation / pulse height deficit, light collection, and PMT effects so I didn't make an effort to find a scaling factor from the simulated to the measurements because it would inevitably involve a fudge factor.  By just plotting the average I got around this (integration sweeps all sorts of stuff under the rug) and can then argue that because I got the trend correct for what I am intrested in, my simulation is good.

Actually, all that it tells me is that it isn't wrong, but doesn't prove that it is correct.

Parallel Geant4!

After a long and frustrating process I finally got Geant4 to run in parallel!  Who knew setting up this stuff could be so hard?  I liked it better a Fermi Lab / CMU where all the environment was taken care for you.

Now, to the forefront of nuclear science!  Researchers at UTK / ORNL want to create ultra cold neutrons, slow them down to ~10-30 K, and "drop" them down a 100 foot tube to look for flavor oscillations of the quarks in neutron - anti-neutron oscillations.  It's a really nifty idea!  I didn't know that neutron's could oscillate between anti-neutrons, but it makes sense; I mean, why not?

Expression Trees / Networkx

Our next lab in machine learning is symbolic regression (fitting a function) using genetic programing.  It's a neat (though a little bit contrived) example of genetic programing.  Our programs are expression trees which we mutate according to a fitness function (the least square error).

Simple Expression Tree

Our actual function to fit just looks to be a sum of sine's, so it would be really cool if I could find an expression tree that would just take the Fourier transform, pick out the principle components, and return as sum as sines.  I have been using the networkx (published by LANL) and so far it has been really nice, but the trees aren't recursively defined so it takes a little bit of thinking to evaluate (rather than a simple post order traversal). Plus (the reason why I choose it) is the interface with Graphviz, which makes it quite easy to visualize trees.  The windows interface is a little clunky (use dotty to draw) but it worked great on the Mac.

Now if only my real research was going so well . . .

Frequency of Names

A while back I got into playing with the cenus data on baby names in order to show the odds between picking a girls name that ends in 'ie' vs 'y' - I always thought that 'ie' would be the more probable choice, but that could be because of dating a girl whose name ended in 'ie'.

 I downloaded the data set from  the SSA (http://www.ssa.gov/oact/babynames/limits.html), and parsed it for the total number of females born in a year, and the number of names that in the the sufix 'ie' or 'y'. Well, in 2011 11% of the girls named ended in 'y', while only 5% ended in 'ie'.  So if you were guessing on the spelling go with 'y'!

 I also looked a the occurrence of biblical names by finding a data set of about 2,000 names that were mentioned in the bible.  I didn't do anything clever with different spellings, just a straight string comparison.  The decline up to the 20's make sense, but then the divergence between the male and female names don't make sense.  This could be because of spelling.  I also find the increase in biblical names in the 1940's to 80's very curious.  The greatest generation falling back on their roots?  Or simply past the 80's the hippies started to have kids named Sunshine?

 Along a similar vein I tried to look if parents were more likely to name their child after a president. I tried to normalize out the effect of names become more popular by using a normalizing the amount of children born during a presidents term by the number of children born in the last 10 years of that name, but I don't think I was successful, simply because the strangest presidents and vice presidents corresponding to the peaks (people name their kids after Dick Cheney?).  The only peak I think if physical is the 1960's, for JFK.  I think the main problem is that most presidents have pretty non-nondescript names, which have a very fluid popularity.

Legend should read POTUS, !PTUS