One week to do it all – Days 4-7: Diffractive data taking

19th February 2016 – On Thursday morning the first fill reached “Stable Beam”. We had prepared a sequence to move the ALFA detectors so, with the push of a bottom, they were all moved to exactly the right position for loss maps. The fill had 42 bunches (as opposed to the 3 bunches used in elastic data taking), so the trigger rates were much higher than before.

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One week to do it all – Day 3: Preparing for Stable Beam

18th February 2016 – Tuesday at 23:55 I called the ATLAS shift leader and told them to stop the elastic physics run and ramp down the inner detector as the elastic program was over. But that’s when the problems started. For some reason, the inner detector could not ramp down and ATLAS requested – for the safety of the inner detector – that the LHC team touch nothing until the problem was solved. While this actually gave us more time taking data for elastic physics, LHC operators and representatives from the other experiments in the CERN Control Centre were really not too happy about the situation.

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One week to do it all – Day 2: Elastic data-taking

17th February 2016 – No time to waste after the alignment. We had moved the detectors to about 2.8 mm from the beam, but the rates of particles passing the detectors indicated a very high background (mainly particles from the beam halo) so we decided to move the detectors out to about 3.5 mm. Now it was time for data taking. Since the detectors were so close to the beam, the LHC could not declare “Stable Beam”. Therefore ATLAS was prepared to manually override the normal safety feature, which only allows the tracking detectors to be powered fully once the LHC declares “Stable Beam”.

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One week to do it all – Day 1: Setting up

16th February 2016 – I have the pleasure to work for a very special sub-detector of ATLAS, called “Absolute luminosity For ATLAS” or ALFA in short. ALFA aims to measure protons at very small angles relative to the beam. To measure these small angles, ALFA is installed on the beam pipe about 240 m away from the interaction point (IP) of ATLAS. The ALFA detectors can move inside the beam pipe in order to get very close to the beam. The detector is only used a few days out of the year when LHC is running with a very special beam setup.

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The hills are alive, with the sound of gravitational waves

15th February 2016 – It’s 16:00 CET at CERN and I’m sitting in the CERN Main Auditorium. The room is buzzing with excitement, not unlike the day in 2012 when the Higgs discovery was announced in this very room. But today the announcement is not from CERN, but the LIGO experiment which is spread across two continents. Many expect the announcement to be about a discovery of gravitational waves, as predicted by Einstein in 1916, but which have remained elusive until today…

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Heavy Ion Collision in ATLAS

ATLAS completes first year at 13 TeV

16th December 2015 – As 2015 draws to a close, the ATLAS experiment wraps up its first phase of operation at a record-breaking energy frontier.

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ATLAS High Performance Computing Initiative Wins Award

11th December 2015 – The Chinese Academy of Sciences (CAS) has awarded members of the ATLAS computing community first prize for their novel use of supercomputer infrastructure.

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ATLAS Computing Infrastructure

Behind very great results lies great computing

13th November 2015 – At the ATLAS experiment, masterful computing infrastructure is transforming raw data from the detector into particles for analysis, with a set direction, energy and type.

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New ATLAS results presented at Quark Matter 2015

7th October 2015 – Heavy-ion physics is the study of the hot dense medium created shortly after the Big Bang. Physicists examine this medium in three collision systems: lead-lead, proton-lead and proton-proton collisions.

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New insight into the proton-proton ridge

2nd October 2015 – The new results confirm that the ridges in proton-proton, proton-nucleus, and nucleus-nucleus collisions have a similar origin. The results also show that the observed weak dependence on the numbers of charged particles and the centre-of-mass energy should provide strong constraints on the mechanism responsible for producing the ridge in proton-proton, and, maybe, proton-nucleus collisions.

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