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Project Title: MRI Consortium: Developments for a Novel Pixel Tracking Layer for the ATLAS Detector Annual Project Report for first year. Date September 2, 2011 We are making excellent progress on the development of the novel pixel layer. In particular we are ahead of most of our milestones and the detector layer is planned for installation during the 2013-2014 shutdown of the LHC accelerator. Progress reports for each institution follow below, some highlights are as follows: The first version of the frontend chip has worked extremely well and we will be submitting the final chip for fabrication by the middle of September. The prototype chip has been used in an extensive beam and radiation program to qualify sensors that have been specially developed for the pixel detector layer. These sensors are planar n-on-n silicon sensors which are 200 microns thick with slim, 200 micron, edges and 3-D silicon sensors which are 230 microns thick with 200 micron edges. The frontend chip and 3-D sensors are new to the field and have the potential for applications in other experiments. At present both planar and 3-D sensors function well and it is likely that both will be used in the final device, chosen for use in areas of the detector where they offer maximum advantage and keep costs low. The planar are best for tracks close to normal incidence while the 3-D should allow better performance for inclined tracks because of a more predictable field distribution within the silicon. Important work expected during remainder of 2011: tests of the final frontend chip, and production and tests of prototype staves which combine a number of bump bonded sensors on a mechanical structure with readout cables. University of Iowa Prototype of the electronic cards in the LVPP4 have been constructed by The U. of Iowa technicians. The original schematics from Wuppertal were modified according to the IBL needs, and constructed at the electronic workshop at Iowa with some help from the engineers. Two opto-isolator cards, an interboard card and a backpanel card were completed, brought to CERN and preliminary load tests done. These proved satisfactory. A complete test with the PVSS requires an independent test stand setup. This is underway at CERN with Mallik and an Iowa postdoc. A Weiner power supply and a partially full LVPP4 crate which requires a special transformer, its associated cable, a strong front panel which supports the stress of the connected cards and the heavy cable is being assembled. A test with Stave0 is planned for the beginning of October and LVPP4 is expected to participate in the test. University of Hawaii Sherwood Parker has continued his work on novel 3-D pixel sensors. This has included beam tests and advice on design and processing. This effort has been very successful with the first demonstration of good production yield of significant numbers of full size (2cmx2cm) sensors. These have performed well in the beam test and the present plan is that about 25% of the IBL detectors will be of this type. They will be arrayed to cover the large rapidity region where they offer advantages because of the electric field distribution in the case of highly inclined tracks. SUNY Stony Brook Stupak (grad student) implemented the initial geometry layout of IBL in ATLAS simulation software and later participated in the IBL performance task force, that showed vast improvement in the physics reach due to the addition of the IBL to the current ATLAS pixel detector. This work culminated in Technical Design Report, which was later approved by the ATLAS collaboration and the LHCC. DeWilde (grad student) and Tsybychev are co-authors of three NIM papers resulting from the 3D pixel sensor test beam work that included measurements of charge collection, tracking efficiency and charge sharing between pixel cells, as a function of track incident angle, and were performed with and without a 1.6 T magnetic field oriented as the ATLAS inner detector solenoid field. Those studies have culminated in the recent ATLAS sensor technology review committee recommendation to populate 25% of the modules with 3-D pixel sensors, covering the forward region of the detector, where they expect to perform better than planar sensors after irradiation. Oklahoma State and University of Oklahoma Oklahoma State and the University of Oklahoma work together on the Opto- box part of the IBL. This includes three flavors of optobox. The lead for Oklahoma is engineer Rusty Boyd. Oklahoma State has employed EE student Steven Welch. A list of the major components of an optobox and the current status of the components is as follows: Major Components of an Optobox Optobox connector boards for B,D boards Optobox assembly Optoboards Optobox Motherboard Optobox Connector board assembly Component Status B Optoboard – Prototype in Assembly D Optoboard – Design Phase B Connector Board – Prototype in Assembly D Connector Board – Prototype in Assembly Prototype Motherboard – Design Phase B Optobox Prototype – In Manufacturing UC Santa Cruz In this first year of the IBL MRI grant, we have continued our evaluation of silicon sensors with regard to radiation hardness and charge collection efficiency. The IBL collaboration has decided to proceed with planar n-on-n sensors for the IBL staves but to continue fabrication of sufficient 3-D sensors to possibly populate the outer 25% at the ends of each stave along the beam direction. This latter option is due to the improved performance of 3-D sensors for steeply inclined tracks. The final decision on which technology to use for the outer 25% will be made after modules are built but before stave integration begins. As a result of our R&D work on “slim-edge” technology and our initial tests of its application to n-on-n devices, lead by Vitaliy Fadeyev, some of the n- on-n planar sensors will be fabricated on wafers with lattice structure 100 instead of the normal 111. This is to facilitate tests of the UCSC “slim- edge” technology on these wafers. Further tests of these wafers are continuing. The electrical services are still in the design and early prototyping phase. Our engineer Ned Spencer was asked to direct the grounding and shielding aspects of the design given the success of his work on the now operating ATLAS SCT detector. He has been working closely with our collaborators at SLAC and CERN to assure effective shielding of the entire IBL structure as well as proper routing of power, signal and ground connections. There are still design issues with regard to how the services will fit in the available space and how the integration of those services can be performed within the space constraints. Another of our technical personnel, Sergei Kachiguine, was enlisted to design a small interconnect printed circuit board to facilitate these connections during integration. Sufficient quantities of material have been purchased for prototype assemblies and that fabrication is proceeding. As yet, no undergraduate students have contributed to testing but we expect that to start once prototype assemblies are ready. Ohio State University The Ohio State group has fabricated the first prototype optical modules for the IBL project. This prototype module is designed to communicate with seven pixel modules instead of eight due to a historical reason. There are multiple design improvements over the modules built for the current pixel detector. Consequently the fabrication was considerably simpler and six modules were successfully fabricated. Four modules were irradiated in August with 24 GeV/c proton and the degradation in the optical power is quite modest. The Ohio State group will design and fabricate the next prototype which will communicate with eight pixel modules as in the final IBL system. Two undergraduates are involved in the project. They both participate in the building of the test circuit boards and data acquisition and analysis of measurements. Brandeis During the last year we have established the basic design for the Long Guide Tube. We have built a prototype that includes the tension rod, internal RASNIKs (four overlapping 3-point straight line sensors) to monitor the shape of the tube. We have also built the control system for operating the LGT. We established the basic operating mode in which feedback from the internal monitors translates into tube shape parameters and tension adjustments. This prototype was built at Brandeis then disassembled, shipped to CERN, and reassembled in building 180 to be used with the Inner Detector mock-up being built there. Figure 1 is a picture of the LGT, with control system, installed in a mock-up of the new beam pipe. The next steps at CERN will be to exercise this prototype in the ID mock-up and compare the performance to design calculations and further develop the control program. At Brandeis we will build a beam pipe mock-up with the same mechanical compliance loading as the actual beam pipe. In addition, we will work with extruders to develop a pre-stressed aluminum guide tube to reduce the dependence of the operation on the tension rods. University of New Mexico UNM led irradiations of the FE-I4 frontend chip and several candidate sensor technologies in the LANSCE 800 MeV proton beam. The UNM contribution included development, submission, and defense of the proposal for beam time, preparation of the samples, electrical characterization of some of the devices before and after the run, staffing of shifts and operations at the beam, real-time monitoring, dosimetry, and facilitation of communications and transport of devices between LANSCE and ATLAS collaborators. During this year we also assessed operation of the HVPP4 Current Monitor system in the baseline pixel detector to understand design modifications required for current monitoring in the IBL. At this time it appears that the primary modification will be to the interrogation of the ELMB status. Current Monitor work is ongoing. UC Berkeley During the first year of the MRI UC Berkeley carried out testing and characterization of the FE-I4A integrated circuit. First wafers were received in October 2010. In parallel, one wafer was diced to load single chip test boards and another 2 wafers were tested on a probe station. Frank Jensen obtained his UCB undergraduate degree and then worked full time on both of these activities until April 2011. He is now starting graduate school at the University of Colorado. The testing included irradiation at the Los Alamos LANSCE facility in Dec. 2010. Two current USB undergraduate students, Devlin Mallory and Ming-Yu Hu joined the testing effort part time in early 2011. Based partly on these test results, a design update of the FE-I4 chip began in February 2011, with a planned submission date of early September 2011. This submission is expected to lead to the production chip for the IBL, called FE-I4B. University of Washington Prototypes of the support tube have been fabricated and are being tested. A mockup of the detector package has been made allowing tests of the mechanical items as a unit. The removal of the beam pipe and then insertion of the IBL is a very delicate process since the space available is extremely tight. Both Lubatti and two engineers have been at CERN for extended periods of time in order to have available a first prototype in August, which is fabricated in 5 sections and assembled and bonded at CERN. In addition, Washington has been been asked to co-bond a conducting skin to the outer surface to provide an EM shield. This adds several layers of complications because it will require a kapton with cooper mesh design that can be co- bonded on each piece of the IST and then develop a way of making contacts from one section to the other after the IST is assembled. This will require some R&D which involves making short sections of the male-female ends with some thin conducting sheets to test our procedures and develop a scheme for electrically connecting from one section to the other.
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