UO physicists gain data leadership roles at CERN's ATLAS program

The Large Hadron Collider at CERN in Geneva is shut down for scheduled retooling, but as crews work to double its energy capacity for proton collisions to 14 trillion electron volts (TeV), two University of Oregon physicists are rising into pivotal leadership roles for the data handling system of the ATLAS experiment.

The UO's Eric Torrence was chosen by the ATLAS institutional board, made up of a representative of each participating institution, to serve as data preparation deputy coordinator effective in October and then as coordinator for a year beginning in October 2014.

David Strom, who was trigger coordinator for ATLAS during the collisions at 7 and 8 TeV, in which the elusive Higgs boson was likely found, was chosen by the ATLAS Trigger and Data Acquisition (TDAQ) system's institutional board as TDAQ co-leader, effective Aug. 1. In March 2015, he will begin a one-year term as overall project leader for the system.

The ATLAS collaboration currently includes scientists and graduate students from 177 participating universities and laboratories around the world.

Strom and Torrence are experimental physicists and members of the Oregon Center for High Energy Physics, a research program led by James Brau in the UO's Department of Physics.

"David and Eric are well known and highly respected in the collaboration, which led to their selection out of very strong slates of candidates," said Brau, Knight Professor of Natural Science and one of the world's leading particle physicists.

The center's newest particle physicist, Stephanie Majewski, who joined the UO in 2012, also is active in helping to upgrade the Large Hadron Collider for its resumption, which is scheduled for April 2015. Majewski, who previously worked at CERN as member Brookhaven National Laboratory's team before joining the UO, is installing demonstration hardware into the detector for the next phase of experiments.

The TDAQ system collects all data from experiments and decides which of the few hundred of the billion interactions that happen each second in the detector are worth saving for future studies.

Strom says his new duties shift his focus from day-to-day concerns as trigger coordinator to a management position involving hardware and infrastructure.

"For example, at the moment, I am working on the technical design report for the Phase I upgrade of the trigger system," Strom said. "We are expecting that the LHC will soon produce three times as many collisions each second than were foreseen in the original design of the detector. To accommodate this we are changing the electronics in part of the detector and also adding new detector elements called muon chambers. We will also be new adding pattern recognition capabilities to the trigger that are much more powerful than what was designed 10 or 15 years ago."

Muon chambers make up the outer layer of the experiment. Muons are negative-charged elementary particles with a mass 209 times that of the electron. The presence of these short-lived particles can be picked up by the signals they leave inside the chambers.

Torrence says his new leadership roles in data preparation involve areas "that don't neatly fit into the other organizational boxes."

"The main theme is to take the raw data that is written by the detector under the control of the trigger, calibrate and reconstruct that data on hardware managed by computing, monitor and assess the data quality, and, finally, provide the data in a useful format which can be used by the physics-analysis groups," he said.

In the areas that Strom and Torrence will be leading, there are several hundred people who are directly involved. "The coordinator positions are similar to vice presidents in a corporate or university environment who need to make sure that everything is moving in the right direction and have the vision to step in and try to fix things when they are not," Torrence said.

Strom also noted that a contingent of UO physics graduate students is looking forward to joining the UO group at CERN for the restart of experiments.

ATLAS is one of two general detectors involved in six experimental programs at the Large Hadron Collider. More than 3,000 scientists from 38 countries are affiliated with ATLAS research, one of the largest collaborative efforts being done in the physical sciences. The ATLAS detector is 148 feet long, 82 feet wide and 82 feet high; it weighs 7,700 tons.