ATLAS Diamond Beam Monitor (J1-5438)

Duration: 1.8.2013 - 31.07.2016
Project type: ARRS research project

Project leader: Marko Mikuž
Coworkers: Vladimir Cindro, Rok Dolenec, Andrej Gorišek, Borut Paul Kerševan, Gregor Kramberger, Boštjan Maček, Igor Mandić, Marko Mikuž, Rok Pestotnik, Andrej Studen, Aleš Svetek, Marko Zavrtanik, Anže Zupanc
Partners: Jozef Stefan Institute, University of Ljubljana, Faculty of Mathematics and Physics

The spearhead of research in particle physics in the coming decade will be directed towards two frontiers: the energy frontier at the Large Hadron Collider and the precision frontier at the B-factories. The ultimate goal of these complementary approaches is to establish signals of physics beyond the Standard model. The road to the required sensitivity is via the increased luminosity, e.g. a tenfold increase of proton-proton collision rate in the upgraded LHC (sLHC) is planned.

The increased luminosity poses requirements that cannot be coped with by a substantial part of the current detector systems. The main burden of the sLHC is the tenfold increase in particle rates. This results in increased detector occupancy and subsequent radiation damage, especially in the innermost tracking detectors that will have to be replaced. The proposed project is aimed to provide support to the upgrade of the innermost tracking layers of ATLAS as well as to generic research on position sensitive particle sensors based on chemical vapour deposition (CVD) diamond.

The central goal of the project is the construction and installation of 24 diamond pixel detector modules into ATLAS by summer 2013. This is carried out as part of the ATLAS Insertable B-Layer project, which aims at the installation of an additional pixel detector layer in the LHC upgrade shutdown in 2013. The diamond pixel modules will be installed in the forward region (at eta~3) as 8 telescope assemblies (4/side) of 3 modules pointing to the interaction point. The purpose of this Diamond Beam Monitor is on-line monitoring of bunch-by-bunch luminosity and beam spot position. Each of the modules is based on a polycrystalline CVD diamond sensor with an active surface of 17.8 mm x 20 mm, divided into 26880 pixels of 50 um x 200 um. The sensor cells are individually bump bonded to the FE-I4 readout ASIC. The optical readout feeds the data into two parallel DAQ streams. One is triggered quasi-randomly and is sampling the 3564 individual bunches of the LHC orbit, the other is responding to the ATLAS L1 trigger. The aim of the first (private) data stream is to extract beam parameters as luminosity and beam spot position in an unbiased way, while the second is adding DBM data to ATLAS physics events.

The construction and operation of the DBM represents an important step towards the ultimate goal: the construction of one or two diamond sensor based tracking layers for the inner detector exchange for the Phase-II of the LHC upgrade around 2020. The aim is to limit the material in these innermost tracking layers below 1 % of radiation length. Diamond is a promising material in this strive because of its low Z, good radiation hardness, negligible leakage current and superb thermal conductivity. The sensor can operate at an almost arbitrary temperature and by itself does not require cooling, which can significantly simplify construction of the tracking layer(s).

The research will be carried out in the scope of the ATLAS IBL project and the ATLAS R&D upgrade project on diamond vertex detector.as well as in the framework of CERN RD-42 collaboration.