Thomas Jefferson National Accelerator Facility
From February until the end of August in 2001 I was working under Professor Rory Miskimen at U. Mass. Amherst. My work was used in the Primakoff Experiment, or PrimEx, which was being performed at the Jefferson National Accelerator Facility. The experiment was completed by Thanksgiving, 2004. My project was to develop, test, and implement a fast-trigger logic system for use in PrimEx.
The aim of the Primakoff Experiment is to perform a precise measurement of the neutral pion lifetime using the small angle coherent photo-production of the pi-zero in the Coulomb field of a nucleus, known as the Primakoff effect. The pi-zero to gamma-gamma decay proceeds primarily via the chiral anomaly and represents one of the most definitive tests of low-energy Quantum Chromodynamics, or QCD.
QCD is the study of how quarks and gluons interact with one another. While a pion is the lightest kind of meson, where a meson is structured by one quark and one antiquark. Also, "pi-zero" is just shorthand for a neutral pion, or a pion that has zero charge.
In simple terms, we want to measure the pion's lifetime. Pions have an extremely short lifetime. So short, that we can't measure the pion's existence via direct observation. However, when a pion decays it leaves behind two photons. Mapping out the trajectories of these photons would lead us to the final location of the pion. Thereby, knowing the point in space where the pion originated and where it decayed--where the photons path started from--would let us calculate the pion's lifetime to a high degree of precision.
The front and back of the wall of detectors, stacked painstakingly, piece by piece...
The pairs of photons collide with a wall of sensors, or photo-multiplier tubes (PMT's). The grid of sensors let us observe at what two points the two photons land. Using a fast trigger-logic system we perform a rapid series of logical operations on the electronic signals being sent from the PMT's, calculating and recording precise locations of the photons.
Fast-Trigger Logic System
The core of the fast trigger-logic system that I developed is a series of CAMAC modules in a CAMAC crate. The components in the crate are controlled by several LabView programs on a regular Windows PC. I had to test various components that served our needs, help configure them, write the LabView programs that use them, and test the whole system so that it would operate in the actual accelerator hall. It turns out that in the end everything worked out great!
