Tag Archives: detectors

Los Alamos: Moving Beyond the Manhattan Project

Blueprints of the atomic bombs developed at Los Alamos during World War II are on sale today in the town's bookstore.

Blueprints of the atomic bombs developed at Los Alamos during World War II are on sale today in the town's bookstore.

No tour of American science would be complete without a stop in Los Alamos, New Mexico. From 1943 to 1945, the U.S. government sequestered many of the world’s leading physicists on this high desert plateau under the auspices of the Army Corps of Engineers Manhattan Engineer District with the mission to build an atomic bomb before the end of World War II. Until they accomplished their goal, hundreds of scientists, along with their families and a large administrative and technical staff, disappeared from their former lives, leaving behind only an address for a P.O. Box in Santa Fe, New Mexico. (You can check out all their staff badge photos here.)

While most of Los Alamos’s new inhabitants left soon after the use of their invention ended World War II, some stayed. The town of Los Alamos soon became a place with real addresses, accessible roads, great mountain biking, and some of the best public schools in the state of New Mexico. But it still carries the weight of its history, with blueprints of Little Boy and Fat Man (the atomic bombs dropped on Hiroshima and Nagasaki) for sale in the town bookstore, and classified weapons research ongoing at the lab. We went there not really sure what we would be allowed to see or how we would feel about it. But while the history was problematic, the current (unclassified) science we saw exhibited many of the same traits we observed at other labs: creativity, ingenuity, and a lot of foil.

Upon observing the success of the Trinity "gadget" on July 16th, 1945, Oppenheimer visibly relaxed years of built-up tension then quoted a line from the Bhagavad Gita: "I am become death, the destroyer of worlds." Success it was: just 0.025 seconds after detonation, the explosion was several hundred meters across. As physicist Kenneth Brainbridge remarked: "Now we are all sons of bitches."

Upon observing the success of the Trinity "gadget" on July 16th, 1945, Oppenheimer visibly relaxed years of built-up tension then quoted a line from the Bhagavad Gita: "I am become death, the destroyer of worlds." Success it was: just 0.025 seconds after detonation, the explosion was several hundred meters across. As physicist Kenneth Brainbridge remarked: "Now we are all sons of bitches."

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The Battleship in the Soudan Mine: MINOS Part II

The MINOS Far Detector, buried 2,341 feet beneath the earth in the Soudan Mine in northern Minnesota. A mural by Joseph Giannetti about the power of science is painted on the right wall.

The MINOS Far Detector, buried 2,341 feet beneath the earth in the Soudan Mine in northern Minnesota. A mural by Joseph Giannetti about the power of science is painted on the right wall.

After visiting the point of origin of the MINOS neutrinos on our Fermilab tour at the beginning of the trip, it seemed a fitting conclusion to stop by their destination as my own road neared its end. So with Lizzie in Mexico, I made the Summer’s last science-related stop at the Soudan Mine with my friend Sam on our way back across the country.

As discussed in our previous post, the MINOS experiment uses a beam of neutrinos called NuMI (Neutrinos at the Main Injector) produced by decaying protons from Fermilab’s Main Injector. These neutrinos travel 450 miles through the earth to the 2341-foot deep Soudan Mine in northeast Minnesota (and beyond, of course), where physicists can isolate the Far Detector from just about any interference. Despite the fact that the detector is shaped like an enormous stop sign, only a tiny number of neutrinos obey the symbolic request: of all the trillions of neutrinos produced by NuMI, the Far Detector sees only about one a day.

Courtesy of Fermilab.

Courtesy of Fermilab.

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Neutrinos and the Intensity Frontier: Fermilab Part II (& MINOS Part I)

The enormous hole in the MINOS building that leads down to the NuMI neutrino beamline and MINOS's near detector.

The enormous hole in the MINOS building that leads down to the NuMI neutrino beamline and MINOS

In all the fuss about how amazing the LHC is going to be, we often forget that there are things it won’t be able to do. One of the most glaring holes in the LHC’s research program is how little work it plans to do on neutrino physics, one of the most exciting and promising fields in the quest to go beyond the Standard Model. Neutrinos are elementary particles that are nearly massless and have no charge. They rarely interact with other particles, so you need to make a lot of them to have the faintest hope of detecting just a few in experiments. In other words, you don’t need very high energy protons to produce neutrinos, but you do need a lot of lower energy ones.

It wouldn’t really make sense to devote much of the LHC’s particle yield to experiments that don’t need anything approaching its high energies, especially during the early years of the experiment. So Fermilab, somewhat presciently, is stepping in to fill the gap. As our tour guide and gracious host Kurt Riesselmann told us, “Fermilab is moving from the energy frontier to the intensity frontier” — meaning that instead of producing a small number of the highest possible energy particles, the lab is figuring out how to make as many lower energy particles as possible.

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A closer look at RHIC

A panoramic view of the PHENIX detectors building and counting house. To the left, an entrance to RHICs particle beam ring is visible. When access is required, the enormous concrete slabs that block the entrance are removed with a crane to expose the route into the tunnel.

A panoramic view of the PHENIX detector's building and counting house. To the left, an entrance to RHIC's particle beam ring is visible. When access is required, the enormous concrete slabs that block the entrance are removed with a crane to expose the route into the tunnel.

The Relativistic Heavy Ion Collider (RHIC) at Brookhaven is a medium-to-high-energy machine that plays a unique role in the study of the early universe. While most particle accelerators collide single particles (like protons and antiprotons in the case Fermilab’s Tevatron), RHIC’s main purpose is to collide gold nuclei, each of which contains 79 protons.

Why the additional mass? The results of a proton-antiproton collision usually look something like this:

A proton-antiproton collision at the Tevatron

A proton-antiproton collision at the Tevatron (courtesy of Rockefeller University/CDF)

Gold ion collisions produce tracks like this:

A gold ion collision at RHIC

A gold ion collision at RHIC (courtesy of RHIC, found on Wikipedia)

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