Toward a high-intensity
muon source

Impact of a single pulse of 12 x 10¹² protons at 14 GeV on a 1cm-wide jet of mercury flowing at 15m/s in a 10T solenoid field: a) at the moment of impact (T=0); b) 9ms after impact; c) 15ms after impact.

To solve the mysteries of nature, physicists operate accelerators that deliver beams of particles including electrons, positrons, protons, neutrons, photons, neutrinos and nuclei. Particle physicists would like to add a muon accelerator to their list.

Results obtained with the Mercury Intense Target experiment show that this might be possible.

Muons are short-lived particles that are 200 times heavier than electrons. Physicists create muons by smashing a beam of protons into a solid or liquid target. The collisions of protons with atomic nuclei produce pions that decay within a fraction of a second to yield muons.

One of the key challenges for building a muon accelerator is the construction of an intense muon source. To be successful, scientists must build a source that consistently produces a large number of muons without destroying the target. They also must develop a strong magnet that channels these pions into a specific direction before they decay.

In November, physicists working on the MERIT experiment successfully tested a muon source concept developed by the DOE-supported Neutrino Factory and Muon Collider Collaboration. The NFMCC collaboration, which includes scientists from 41 institutions, proposed a target that consists of a free-liquid mercury jet flowing at 20m/s within the confines of a 20T solenoid field. The pions are produced by an intense proton beam that hits the jet with a beam spot size of a few millimeters.

The heat deposited in the mercury jet corresponds to the energy emitted by hundreds of 1kW heaters in a space that is 1cm in diameter and 30cm long. Can the jet survive this heat?

Using the Proton Synchrotron at CERN, the Mercury Intense Target collaboration demonstrated that the jet could, in principle, withstand a proton beam of up to 4MW power.

Left to right, seated: Hugo Pereira, CERN; Harold Kirk, BNL. Left to right, standing: Chris Densham, RAL; HeeJin Park, BNL (obscured); Peter Loveridge, RAL; Roger Bennett, RAL; and Kirk McDonald, Princeton. Image courtesy of Robert B. Palmer.

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Result of the Week Archive

Bad news/good news: Congress takes first steps in FY 2009 appropriations cycle

From AIP FYI,
March 27, 2008

The House and Senate have taken their first steps in the FY 2009 appropriations cycle. While the initial targets for proposed science funding are very favorable, the overall picture is considerably more troubled. As they did last year, the House and Senate are on a pathway to spend more for discretionary programs than what President Bush has proposed, setting up what will in all likelihood be another series of presidential vetoes and an unfavorable appropriations outcome.

The process of determining a budget resolution - a nonbinding congressional spending and taxing "blueprint" - is something that would appear to matter only to those working on Capitol Hill. It matters. The additional $22 - $23 billion for discretionary spending that Congress wanted to spend last year, and President Bush's refusal to spend any more than what he had originally requested resulted in an almost three-month delay in the final passage of the FY 2008 appropriations legislation.

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Have a safe day!

IDES representative on site Friday
A representative from Illinois Department of Employment Security will be on site in the Wilson Hall One West conference room for the last on site visit Friday, March 28. Due to the increase in attendance, two larger group meetings will occur at 11 a.m. and 12 p.m. If you are beginning your furlough week, please fill out a benefit application on site. You may also apply for benefits online or at your local IDES office the week you are on furlough. Please contact Heather Sidman x3326 or Jeannelle Smith x4367 with questions.

SciTech summer camps
The SciTech Hands-on Museum offers Science Adventure Camps for children age 6-8 and age 9+. Week-long camps begin on June 23 and run from 9 a.m. to 3 p.m. Fees range from $200 to $225 per week. Before- and after-care is available for an extra fee. For more information, visit the SciTech Web site.

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