January 18, 2011
Richard Plantagenet was known as Richard, Duke of York and also father of Richard III, King of England. Richard III spent considerable time in Middleham, the village in which I was born. He pretty well ruled England from Middleham Castle. Later, we, the people, built the village from the stones of the castle, but there was enough left for my peers and I to climb into and play in during the summer months. We would climb the tower and look over the land, as Richard must have done and speculate where he was supposed to have killed the princes. And that brings us to the FEL!
In nuclear physics, we explore the structure of matter using high-energy electron beams, exchanging photons with the targets of nuclei, nucleons, quarks and gluons. Condensed matter physicists, chemists and biologists use real photons. They create lasers to get intense beams. The energies of the photons in the lasers are directly related to their colors. Blue photons are higher energy than red photons. Red, Orange, Yellow, Green, Blue, Indigo, Violet (easily remembered as Richard Of York Gave Battle In Vain) are the colors of the rainbow. When we study the colors, each one can be related to a property of the structure of some chemical, its ionization or its excitation, its fluorescence, or its phosphorescence and so teach us about the material. What we can do with Terahertz radiation is pretty spectacular as is the impact of an infrared laser; for example they provide sensitivity to vibrational and other modes of the target material. These are the products, thus far, of the Jefferson Lab Free-Electron Laser.
During the course of 2010, a primary goal of the Free-Electron Laser Division was the establishment of the “UV line” and the production of UV light, ultraviolet light. Going back to the rainbow, ultraviolet is just beyond the violet, just beyond the visible. I recall dancing the nights away with flashing ultraviolet light exciting the white clothes with residual fluorescent dye from the detergent. Between ultraviolet and X-rays is the vacuum ultraviolet regime. These are the color names for photons with energies of a few electron-volts. These are the binding energies of electrons in materials, such as metals, and high-temperature superconductors. That means that we can study the properties of materials, such as the high-temperature superconductors and perhaps, by understanding how they work, we can fabricate new versions and can extend their technological impact. This is conceivable, if the intensity of the light is high, and from our exceptional FEL, it is much higher than that from conventional X-ray sources. There are only a couple of comparable sources in the world, none in the United States.
For some years, the Jefferson Lab FEL has been a world leader in free-electron laser power. Strongly supported by funding from the Office of Naval Research, it achieved somewhat in excess of 14 kilowatts in the infrared. The extension of operation into the ultraviolet has the potential to open a new vista. These are the wavelengths of choice of our scientist colleagues. These are the colors they seek. We hope to execute a number of high-profile experiments proposed by scientists from across the U.S., during the next year. We hope to convince others, such as the Commonwealth of Virginia and the Basic Energy Sciences office of the Department of Energy Office of Science that we can provide for top-class science. They already support our accelerator R&D work, why not the science.
A scientific presentation was made in a colloquium here at Jefferson Lab a couple of weeks before the holidays. When we recently made a press announcement about the ultraviolet operation, the response from the press was extensive as can be seen on the sites below. We are opening new opportunities; ultraviolet is exciting materials and scientists just as ultraviolet lighting in the disco excited us in our youth!
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