Thursday, May 30, 2013

Have a safe day!

Thursday, May 30

1:30 p.m.
LHC Physics Center Topic of the Week Seminar - WH11NE
Speaker: Markus Schulze, Argonne National Laboratory
Title: Associated Top Quark Pair Production: A New Era in Top Quark Physics

2 p.m.
Special Seminar - Curia II
Speaker: Daniel Bowring, Lawrence Berkeley National Laboratory
Title: Muon Ionization Cooling R&D: Using Materials Science Tools to Solve Accelerator Physics Problems

2:30 p.m.
Theoretical Physics Seminar (NOTE LOCATION) - WH3NE
Speaker: Patrick Draper, University of California, Santa Cruz
Title: Two Vacuum Vignettes

3:30 p.m.

4 p.m.
Accelerator Physics and Technology Seminar (NOTE DATE, LOCATION) - Curia II
Speaker: Timofey Zolkin, Fermilab/University of Chicago
Title: A Model Ring with Exactly Solvable Nonlinear Motion

Friday, May 31

3:30 p.m.

4 p.m.
Joint Experimental-Theoretical Physics Seminar - One West
Speaker: Émilien Chapon, CEA Saclay
Title: Probing the Electroweak Sector at DZero with WW Production and other Diboson Final States

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Wilson Hall Cafe

Thursday, May 30

- Breakfast: Canadian bacon, egg and cheese Texas toast
- Breakfast: corned-beef hash and eggs
- Monte Carlo sandwich
- Mediterranean-style ziti with asparagus
- Beef stroganoff
- Buffalo chicken tender wrap
- Grilled- or crispy-chicken Caesar salad
- Chef's choice soup
- White-chicken chili

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Chez Leon

Friday, May 31

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Special Announcement

Sitewide siren maintenance this morning

This morning between 9 a.m. and noon, maintenance will be conducted on the five outdoor sirens located throughout the Fermilab site. As part of the maintenance, each siren will be independently activated for a brief period of time. If there is an actual emergency, the sitewide emergency warning system will be used to send out instructions.


Smaller, more powerful test stand for superconducting cables at Fermilab

The Superconducting Strand and Cable R&D Group recently built a new superconducting cable test stand, located in Industrial Building 3a. Its transformer, made of coiled superconducting wire, is attached to the stand about two feet from the ground. Photo: Sarah Khan

Testing key magnet components has become ever more important to Fermilab's High-Field Magnet Program, especially since the recent development of an 11-Tesla superconducting magnet.

To test the cables for such magnets, the Technical Division's Superconducting Strand and Cable R&D Group recently built a test stand able to deliver almost 15-Tesla fields, trouncing the capacity of similar facilities at a fraction of the size and cost. Such high fields means the group can now test magnet cables for the stringent standards of the LHC luminosity upgrades and other projects.

"This facility has a lot of potential, and we're looking forward to using it in future experiments," said Alexander Zlobin, head of the High-Field Magnet Program.

A similar facility currently in use at CERN can deliver a 10-Tesla field, but requires high-current supplies to power the magnet and test cable as well as large, strong mechanical structures to keep from deforming the sample in the magnetic field, said Superconducting Strand and Cable R&D Group Leader Emanuela Barzi.

That and other factors mean it can cost an experiment around $20,000 to prepare and test a single cable at that facility.

Fermilab's cable test stand, however, is built with a compact but powerful solenoid eight inches in diameter and 10 inches tall—small enough to fit on a bookshelf.

"We realized that, with the space constraints we had, we needed to get creative with our design," Barzi said.

The test cable sits inside the solenoid's center hole and connects to a transformer that delivers currents up to 25,000 amps from an input of just 600 amps. The group configured the cable in a way that results in much lower destructive forces than measured at other facilities, and thus less chance of structural damage to small, lightweight components.

All this is done inside a small liquid-helium tank at very cold temperatures, allowing the cables to superconduct.

The final cost is less than $2,500 per cable preparation and test, Barzi said. Some projects have already expressed interest in using the test stand, she added.

"The United States LHC Accelerator Research Program is interested in using this test stand to test cables for the LHC upgrades, and we are also looking into possibilities of using this for versions of muon colliders or Higgs factories," Zlobin said. "This facility would serve well for cable and magnet development for all these very interesting concepts in high-energy physics."

Sarah Khan

Photo of the Day

Woods off Pine

The woods off Pine Street are both stirring and still. Photo: Elliott McCrory, AD
In the News

Research effort deep underground could sort out cosmic-scale mysteries

From DOE Pulse, May 27, 2013

DOE's Oak Ridge National Laboratory has begun delivery of germanium-76 detectors to an underground laboratory in South Dakota in a team research effort that might explain the puzzling imbalance between matter and antimatter generated by the Big Bang.

"It might explain why we're here at all," said David Radford, who oversees specific ORNL activities in the Majorana Demonstrator research effort. "It could help explain why the matter that we are made of exists."

Read more

Frontier Science Result: DZero

Piecing together muons

To piece together many of the particles produced by Tevatron collisions, physicists at DZero must first piece together the muons they decayed into.

To understand the subatomic world, physicists must piece together a picture of the particles made in a high-energy collision using information from detectors as large as apartment buildings. The particles recorded by a detector may themselves be the decay products of unstable particles, like a Higgs boson or a top quark, that don't reach the detector directly. A key particle in this multi-layered puzzle is the muon, a heavy cousin of the electron, that would travel a few kilometers before decaying when it was produced in a Tevatron collision. As a charged particle that packs penetrating power, it leaves a clean signature in the detector that can help physicists piece together the bigger picture. The outermost layers of modern collider detectors are designed just to find muons, and a recent effort at DZero describes, in detail, the process of identifying muons from the detector hardware readout to benefit other experiments with muon detectors.

The DZero muon system includes three layers, each a combination of tracking chambers that accurately determines the muon's location and large scintillation counters with fast readout that measure the muon's arrival time to within a few nanoseconds. Large magnetized blocks of iron fill the space between the first two layers, allowing for a momentum measurement within the muon system. A notable feature of the DZero muon system is that the magnetic field was reversible and systematically flipped, allowing DZero analyses to be particularly sensitive to differences between muons and antimuons.

A new document describes the algorithms used to piece together information from all the individual layers of the muon system into the three-dimensional path a muon might have taken through the detector. Since a muon's signal could be mimicked by other particles, additional criteria are defined that help select real muons while rejecting backgrounds. The paper details these methods and provides the selection efficiency and background rejection rates of the standard sets of DZero muon identification criteria. The wealth of information provided about muon reconstruction and identification is not just crucial historical documentation for DZero analyses, but provides information that will help improve future particle detection systems.

Mike Cooke

These physicists made major contributions to this analysis.
This array of scintillating panels, part of one layer of the DZero forward muon system, provides the muon's arrival time to within a few nanoseconds.

Today's New Announcements

Fermilab Lecture Series: Particles, Fields and the Future - Sean Carroll - June 12

10K Steps participation winner

Fermilab Heartland Blood Drive with Oberweis gift certificates - June 10, 11

International folk dancing cancelled today, moves to Wilson Hall for summer

Windows legacy print server, fermi-wprt, will be retired on June 3

Fermilab Family Outdoor Fair - June 9

Children's art show - June 21

DASTOW scheduled - June 21

46th Fermilab Users Meeting registration now open

Fermilab prairie quadrat study

Volunteer opportunity - Coat Drive 2013

Swim lessons for children

Water fitness at Fermi Pool

Martial arts class

10,000 Steps-A-Day enrollment

Outdoor soccer at the Village

Scottish country dancing meets Tuesday evenings in Auditorium

English country dancing at Kuhn Barn

Raging Waves water park discount