From 2008 to 2011, UNM designed, constructed, installed, and commissioned a system that records in real time the leakage currents of a subset of the pixel barrel modules. Because current in silicon is proportional to fluence, this Pixel Current Monitoring System provides an instantaneous snapshot of the radiation damage incurred by the Pixel detector. Martin designed the hardware, Igor led the commissioning, and Konstantin developed the readout software. From installation through 2014, Rui took responsibility for monitoring the data and providing regular updates to the ATLAS Pixel group. In 2014, Sally, Rui, and Igor compared the data to a prediction based on the Hamburg Model of silicon response to radiation damage and found good agreement. Using the fact that the model incorporates temperature dependence and both beneficial and reverse annealing, we extrapolated what we observed for several future temperature scenarios and used this to infer the operational lifetime of the Pixel detector. The graphical results of the analysis were collaboration-approved in 2014 and are publicly available. Our text document is being released in two stages, as an ATLAS PUB Note, and as a chapter in a comprehensive Pixel Detector Performance paper to be submitted to JINST in 2015. Konstantin presented the results in an invited talk at the 9th "Trento" Workshop on Advanced Silicon Radiation Detectors in February 2014. Igor presented first data at the 22nd RD50 Workshop and included the final analysis in his invited talk, "Radiation Experience with the ATLAS Pixel Detector," at PIXEL2014.
The success of the barrel pixel current monitor system motivated ATLAS to extend the system to the pixel disks, whose radiation damage should be similar to the outermost barrel layer's damage and thus clearly observable in 2015 and beyond. UNM is leading this upgrade. Aidan and Martin are building the electronics. Igor, Konstantin, Sally, Martin, and our students will commission this system in early 2015, and Aaron will remain at CERN to maintain, monitor, and report regularly to ATLAS on the data from the full barrel plus disk system.
Aaron is studying the ATLAS Level-2 and Event Filter trigger algorithms to improve the efficiency of their selection requirements. The increased number of pile-up events caused by the increase in center of mass energy in 2015 makes this study critical to the success of numerous analyses. It is especially important to B-physics, which in many cases depends on secondary vertex reconstruction and retention of low momentum tracks. Aaron is supervised on this, his authorship qualification project, by Pavel Reznicek, who is stationed at CERN.
Igor joined the ATLAS Distributed Analysis Software Team (DAST) in October 2013. From February to April 2014 he served full time as an on-shift expert providing the first point of contact for distributed analysis (ATLAS Grid) questions, including problems related to analysis tools, distributed data management, and offline software. He will continue to contribute to the DAST effort as needed in 2015-19. Konstantin is taking regular shifts as a Detector Control System (DCS) Expert as the Pixel Detector is being commissioned now in summer and fall 2014. When the experiment resumes operation, all of us will provide data-taking shift support of some kind, as we have in the past, including DCS Expert shifts (Konstantin), Inner Detector monitoring (Konstantin, Igor), and Shift Leader (Sally). Aaron, Neil, and Aidan will train for control room shifts as soon as the 2015 schedule is made available.
We maintain and operate an ATLAS subsystem that provides continuous monitoring of radiation damage in the pixel detector through measurement of the sensor leakage currents. Martin designed, built, and installed this system, comprising 85 electronics boards. Rui is responsible for monitoring it, and regularly reports on it to ATLAS. Aaron is training to take over from her when he moves to CERN in 2014. Sally, Konstantin, Martin, and Igor maintain the hardware at CERN. Igor, Rui, and Sally are preparing a paper that compares the observed leakage current distribution to predictions by the Hamburg Model. We find a small asymmetry in the current, recorded in the two halves of the ATLAS pixel barrel. These results were first reported at the 2013 RD50 Workshop.
We meet our ATLAS operations responsibilities as DCS Expert (Konstantin), Inner Detector shifter and previously TRT shifter (Rui), Pixel shifter (Igor), and Shift Leader (Sally). In addition:
UNM has primary responsibility for the electronic design and production (Martin), slow control software (Konstantin), calibration and installation procedures (Igor), and daily monitoring (Rui) of the system that monitors radiation damage in the ATLAS Pixel Detector through measurement of sensor leakage current. Martin's Current Measurement Boards
(CMBs) measure bias leakage current in real time (i.e., without deadtime penalty of special runs) on a per-module basis over the range 0.02 llA to 2.0 rnA while maintaining ground isolation between each of the bias outputs. His ELMB Carrier Boards interface analog voltages representing pixel sensor current through the patch panel backplane to the ELMB board
that interfaces to a CAN computer bus. The full set of 90 CMBs and 40 ELMB Carrier Boards was built at UNM and calibrated by our team. Installation of the boards required the time and expertise of all members of our group from 2011 to 2012; Martin and Sally installed the last boards in June 2012. Rui reports on the status of the system regularly at the Pixel Weekly Operations meetings. Using Igor's temperature and scale corrections, we observe that the leakage current of the
pixel detector is consistent with the Lindstroem-Moll Model to within about 10%, including annealing. Konstantin described the project in his talks at the 2010 Symposium on Radiation Measurements and Applications, the 13th ICATPP Conference, and at the 20th RDSO Workshop in May 2012. Sally reported on it at the
8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors in December 2011. We are currently writing three papers on the project: a hardware technical manual (Martin), a NIM overview of the hardware implementation (Martin and Igor), and a full analysis of the data in the context of available models (Igor, Aaron, and Rui).
We meet our ATLAS operations responsibilities as DCS Expert (Konstantin), Inner
Detector shifter and previously TRT shifter (Rui), Pixel shifter (Igor), and Shift Leader
(Sally). Qufei is training for Remote Data Quality shifts. Konstantin served as Coordinator
of ATLAS Pixel SR1, where he supervised the operation of the pixel ground replica known as ToothPix, in 2010-11. Rui presented a poster
on ATLAS Inner Detector Performance at the LHCC meeting at CERN in March 2012. Sally served on the US-ATLAS Speakers and Deputy Operations Program Manager Search Committees. Sally was also a member
of the ATLAS panel that selected the Insertable B-Layer (IBL) sensor technologies in June 2011. Konstantin is the US-ATLAS b-tagging convener.