The goal of the ATLAS experiment is to investigate fundamental components of matter and their interactions by colliding particles of very high energy in the LHC (Large Hadron Collider) accelerator at CERN. The LHC will deliver two proton beams colliding at energy of 14 TeV and luminosity by two orders of magnitude higher compared to luminosity ever reached in an accelerator. Collection of physical data has started in 2009.
The scientific program of the ATLAS experiment, which is foreseen for about 10 years, comprises fundamental problems related to understanding of nature of the matter. The main goals of the experiments are:
- discovery and accurate measurements of Higgs boson particle, which is a carrier of field responsible for spontaneous brake of symmetry and for the mass of particles,
- discovery and investigation of supersymmetric particles and expected symmetry between fermions and bosons,
- investigation the quark-gluon plasma state of the matter,
- unification of fundamental interactions beyond the standard model
- verification of concepts of additional dimensions of space.
Given a very high luminosity of the LHC it was necessary to develop for the ATLAS experiment new types of detectors based oh high technologies. New challenges that were practically absent in the past particle physics experiments are due to radian damages in the detectors and in the readout electronics. This applies in particular to the tracking detector, which is mostly based on silicon technologies. The team from the Faculty of Physics and Applied Computer Science of the AGH University of Science and Technology participates in development of new detector technologies, building and commissioning of the detector from the very beginning, i.e. since 1996. This activity is carried out in a close collaboration with the Institute of Nuclear Physics of the Polish Academy of Sciences. The major task that have been realised by the team are:
- development of radiation resistant integrated circuits for readout of silicon strip detectors in the SCT (Semiconductor Tracker) detector,
- development of the concept and building of the gas gain control system for the TRT (Transition Radiation Tracker) detector
- design and production of high voltage power supply system for biasing silicon strip detector in the SCT – this task has been realised together with the Institute of Nuclear Physics
- participation in development of HLT (High Level Trigger) steering concept and selection of recorded events
- development of an algorithm for section of events with electrons in final state at third level trigger
- trygger configuration for lead-lead collisions
- production of electroweak bosons with electrons in final states in lead-lead collisions
- charge particle correlations in pseudorapidity in minimum bias lead-lead collisions
- minimum bias trigger in proton-proton and lead-lead collisions
- elliptic flow with pixel tracks.
In parallel with commissioning of the LHC an upgrade program has been started towards the Super-LHC aiming at increasing the luminosity by a factor 10. To use efficiently such a high luminosity the ATLAS detector will require major modification. In particular, a completely new Inner Detector has to be built after about 10 years of running of the present detector. The team from the Faculty of Physics and Applied Computer Science participates already actively in development of the concept of the Upgrade Inner Detector and of advance technologies required for a new detector.
The DETNI project carried out in the EU 6-th Framework Programme deals with development of position-sensitive neutron detectors optimised for high spatial resolution and high-rate applications. These detectors are developed keeping in mind requirements of experiments planned at future high intensity neutron sources, like the ESS – European Spallaton Source. In the frame of the DETNI Joint Research Activity three activity three types of modular detectors and dedicated ASICs are being developed.
Forward Calorymetry for ILC
The International Linear Collider (ILC) is the most likely successor to the Large Hadron Collider (LHC), which should allow much more precise measurements than the LHC, capable of shedding more light on the structure of the elementary components of matter. As is well known, the final decision on where and when to build the ILC has not yet been made and will probably have to wait for the first results from the LHC. Regardless, thousands of scientists from different countries have been working for years to conceptualise and build prototype accelerator and detector systems for the ILC.
The Department of Interactions and Particles at WFiIS AGH is a member of the international FCAL (Forward Calorimetry) Collaboration at the ILC, which is involved in the design and construction of the forward detectors BeamCal, GamCal and LumiCal. The Department’s staff focus mainly on work on the luminosity detector (LumiCal), in particular on the design and construction of the readout electronics, and later on its integration with silicon sensors and the construction of complete detector modules. The joint work of WFiIS AGH and IFJ PAN on the design and construction of the LumiCal detector is probably the only such concrete and advanced contribution of Polish groups in the construction of an ILC detection system.
The silicon luminosity detector will be a sandwich-type calorimeter built of active silicon layers sandwiched by tungsten layers. The main challenge for this detector will be the design and construction of about 200,000 channels of readout electronics, which should meet the following criteria: work for a huge range of input signal (from ~2 fC to ~10 pC, i.e. almost 4 orders of magnitude); be very fast (formation time ~50 ns); work for a very wide range of silicon sensor capacitances (from 10 pF to 100 pF) and consume low power (<1 mW/channel).
In the frame of the RETINA project Group of Nuclear Electronics and Detectors develops multichannel ASICs for readout signal from live neural networks, in particular from the retina, and for electrical stimulation of neurons using microelectrode arrays. The developed ASICs, Neurochip and Platchip, allowed for building in collaboration with Santa Cruz Institute for Particle Physics, UC, Santa Cruz, a 512-electrode system for imaging neural activity of retina. The system is being used in neuroscience experiments carried out at the Salk Institute for Biological Studies, La Jolla. Newly developed ASICs, Neuroplat and Stimchip open new possibilities to expand the developed technology to other fields of neuroscience.
The RX project covers a family of multichannel ASICs for readout of silicon microstrip detectors for position-sensitive detection of X-rays. Development of RX ASICs is driven by applications of silicon strip detectors to X-ray diffaction and X-ray medical imaging. An ASIC from the RX familly developed in the Group of Nuclear Electronics and Detectors is used in the LynxEye detector developed in collaboration with Bruker AXS.
In collaboration with Universita degli Studi del Piemonte Orientale in Alessandria and INFN Torino a prototype system for dual energy X-ray medical imaging is being developed.
The STAR experiment is the largest experiment running currently at Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Laboratory (BNL), New York, USA.
The primary physics task of STAR is to study the formation and characteristics of the quark-gluon plasma (QGP), a state of matter believed to exist at sufficiently high energy densities. Detecting and understanding the QGP allows us to understand better the universe in the moments after the Big Bang, where the symmetries (and lack of symmetries) of our surroundings were put into motion.
Unlike other physics experiments where a theoretical idea can be tested directly by a single measurement, STAR must make use of a variety of simultaneous studies in order to draw strong conclusions about the QGP. This is due both to the complexity of the system formed in the high-energy nuclear collision and the unexplored landscape of the physics we study. STAR therefore consists of several types of detectors, each specializing in detecting certain types of particles or characterizing their motion. These detectors work together in an advanced data acquisition and subsequent physics analysis that allows final statements to be made about the collision.
Scientists from AGH University of Science and Technology are part of the Ultra Peripheral Collisions group, where they work on data analysis of such processes like central exclusive production, elastic scattering, single diffractive dissociation. Also, they are involved in development of the experiment software and upgrade of the Roman Pot silicon strip detectors responsible for tagging protons scattered in the forward direction.
Studies of electron-proton interactions in the ZEUS experiment on the HERA accelerator.
The goal of experiment:
The aim of the experiment is the fundamental study of the elementary constituents of matter and their interactions by high-energy beam collisions. The HERA accelerator at the German Electron Synchrotron Facility (DESY), Hamburg, has made it possible to collide counter-rotating electron/positron beams with protons in the world’s highest energy range (314 GeV). The collisions were recorded with the detector complex by the ZEUS international collaboration from 1992 to 2007. Analysis of the collected experimental data is still ongoing with the aim of research:
- quark-gluon structure of the nucleon and other elementary particles;
- photoproduction and deep-elastic scattering processes in a hitherto unexplored energy region and to verify the predictions of the Standard Model;
- search for the existence of hypothetical particles (leptokark, supersymmetric particles);
- the search for new interaction carriers and the substructure of quarks.
Key findings of the study:
Fifty-two laboratories from 16 countries around the world are participating in the ZEUS international collaboration. One of the conditions for participation was the participation of teams in the design and construction of detector parts. The most important results of the team from WFiIS in the field of detector design and construction are:
- BAC supplementary calorimeter gas system
- participation in the development and modification of the Experimental Luminosity Monitor
Highlights of the results of the e-p impact studies: the ZEUS collaboration published 180 papers in Philadelphia-listed journals between 1992 and 2008. The co-authors of these papers are team members from WFiIS. In particular, due to the fact that part of the apparatus dedicated to the measurement of luminosity in the experiment was designed and built by the Krakow team (WFiIS AGH and IFJ PAN), our participation was mainly focused on the measurements of this parameter, which is essential for the determination of each active cross-section for the studied processes. The Luminosity Monitor apparatus also plays an essential role in the registration of electrons (positrons) at small angles. This, due to the familiarity with the realities of the apparatus, is a natural reason for the activity of the team from WFiIS in the analysis of processes for which the identification of electrons slightly deviated from the original direction was crucial, among others in the study of photoproduction processes, especially diffraction processes. The most important achievements achieved by the ZEUS collaboration include:
- measurement of the total and partial active cross sections ?p at an energy of 210 GeV,
- observing cases with a large break in rapidity and proposing this signature as a selection method for diffraction interactions,
- measurements of the F2 proton structure function, F2D4 diffraction structure function in different kinematic areas,
- observation of a deviation from the Standard Model predictions in terms of large values of quadrupole transmission Q2 and large values of xBj,
- first observation of resonances in the final state K0s K0s,
- the search for pentaquarks,
- precise measurements and characteristics of vector meson production and deep-nonelastic Compton scattering (DVCS) over a very wide kinematic range. These measurements are extremely important for the hitherto unexplored transition region between 'soft’ processes and the interactions described in the Standard Model by perturbative quantum chromodynamics (QCD).
We anticipate that the collected experimental material of the ZEUS experiment will be the subject of analyses (MSc, PhD, postdoctoral) until at least 2012.
K. Piotrzkowski, L. Adamczyk, W. Machowski, A. Kowal, I. Grabowska-Bołd, D. Szuba, J. Szuba, T. Bołd, J. Łukasik
Grants and other research projects:
- Special research projects: „Investigation of electron-proton interactions in the ZEUS experiment on the HERA accelerator at the DESY facility in Hamburg” 115/E-343/SPUB/P3/202/94, 115/E-343/ SPUB/P3/109/95, 115/E-343/ SPUB/P3/120/96, 115/E-343/SPUB/P3/002/97, 115/E-343/SPUB/P3/154/98, 112/E-356/SPUB/DESY/ P-03/DZ 3/99, 112/E-356/SPUB-M/DESY/P-03/DZ 301/2000-2002, 112/E-356/SPB/ DESY/ P-03/DZ 116/2003-2005, 153/DES/2006/03
- Grants KBN: GR-152, 2 P03 B 244 08 p02, 2 P03 B 105 12, 2 P03 B 149 12, 2 P03 B 032 16, 5 P03 B 137 20, 2 P03B 139 22, 2 P03 B 126 25, 1 P03 B 065 27