Lithium 9 Production Rate in a Liquid Scintillator
by Ryan P. Schooley
Supervisors: Dr. Bolton and Dr. Horton-Smith
Welcome to my webpage. This page summarizes my experience doing research for the Summer 2009 at Kansas State University in the High Energy Physics department. We are trying to measure the lithium 9 production rate produced in liquid scintillators. This research is crucial for the Double Chooz (pronounced “show”) in France. The Double Chooz experiment is designed to improve upon previous measurements of the θ13 mixing angle, a parameter for determining the probability of a neutrino changing its flavor eigenstate. It is believed that Lithium 9 production is currently the greatest source of systematic uncertainty in the Double Chooz experiment.
Also, we are investigating the scintillation properties of epoxy. In the Double Chooz experiment, devices measuring the state of the scintillation fluid are covered in epoxy so they do not interfere with the experiment. But if epoxy were to have scintillation properties, the epoxy itself would scintillate, making it a poor buffer. This would add yet another uncertainty to the Double Chooz experiment.
Below, I describe the Project Goals, my Research Strategy, my Research Progress, and will eventually post my Final Presentation and Final Report. I post my homework assignments from our weekly REU scientific Ethics class, taught by Prof. Bruce Glymour and Prof. Amy Lara, and my reaction to Prof. Larry Weaver's Lectures. Scroll all the way down to learn more About Me. Finally, I've included some Useful Links.
Summary Statement: Neutrinos, the ‘ghost’ particles produced by radioactive decay, can transform from one type into a completely different type of neutrino. It is as if you threw a baseball, closed your eyes, opened them a few seconds later and found that the baseball was now a basketball!
In order to fully understand neutrino oscillation, accurate measurements of a parameter, theta 13, must be taken. This involves detecting many neutrinos at one time and then again at a different time. But neutrinos are difficult to detect and theta 13 seems to be small, so the detectors need to be close to the reactors that produce them. But that means the detectors will be close to the surface of the earth where they are more exposed to cosmic particles called muons. Muons are known to interact with detector material and to produce lithium 9. When lithium 9 decays, it looks exactly like a neutrino to the detector. Thus, to get an accurate measurement of theta 13, one must have an accurate measurement of the lithium 9 produced by muons. This is the goal of my research this summer: an accurate measurement of the rate at which muons make lithium 9 in scintillator fluid.
1. Determine the scintillation rate of epoxy.
2. Examine the data output of the Lithium 9 experiment, confirm detector is working properly.
We were able to conclusively determine the rate of epoxy. It does not seem to scintillate. However, a factor of 2 correction may be necessary to account for the ‘brightness’ of the epoxy used in double CHOOZ.
Additional data was collected on the lithium 9 detector. This time, however, the veto was placed on the delayed signal. This produced data that was drastically different than the first batch of data taken by the Dr. Mark Smith (this data had a veto on the prompt signal). We had a feeling that the change in the data was due to the veto affecting which events were counted, but it could also have been due to a miscalbiration or we could have been observing some strange new phenomenon. We set out to eliminate these two options by:
1. Running the detector with a prompt veto again. This would allow us to compare the data to the original to rule out any new phenomenon.
2. Remove the veto completely. This will allow muons to pass through and we could check their energies and confirm the calibration.
The new prompt veto data looked identical to the old prompt veto data. The veto less data produced signals with energies typical of muons. Thus, we ruled out the possibility of new phenomenon and incorrect calibration, concluding that the difference between the new and old data is due completely to switching the veto.
Lectures by Dr. Weaver
Ethics Class: …yeah…
About Me: I'm really interesting! I grew up in Saratoga Springs, Ny, and attend College at SUNY Geneseo. I first got interested in physics when I was a senior in high school. As a freshman in college, I thought I wanted to be a Doctor, so I enrolled as a bio major. I later grew bored with Bio but genuinely enjoyed my calculus classes. I was pretty sure I wanted to do something related to science, so I switched my major to physics in my sophomore year. Then, in spring of my sophomore year, I read about Einstein’s Special Relativity and I knew I wanted to be a physics major.
I enjoy physics, math, reading, working out and running, basketball, and various other things.
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