The Technical Infrastructure Group supplies experimental activities at NBI with technical

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1 TECHNICAL INFRASTRUCTURE Staff: Leif Antvorskov John Engelhardt Fin Hansen Erik Grønbæk Jakobsen Niels Lindegaard Erik Kaimer Olsen Bjørn Rasmussen Jette Sørensen Henrik Bertelsen Finn Ferrall Jimmy Cali Hansen Arne Lindahl Børge Svane Nielsen Ejner Petersen Jens Sørensen Jørn Westergaard Introduction: The Technical Infrastructure Group supplies experimental activities at NBI with technical support. The group sees their role as technical support for all experimental activities at NBI with emphasis on our international commitments in nuclear and particle physics. The aim is to cover a wide enough range of expertise and manpower to be able to contribute in a significant way to experimentation in international collaborations. In addition, we provide in-house support of technical kind at the institute, such as support of PC and printer equipment, building maintenance and student projects. The mechanical workshop and our electronics experts also produce and maintain a number of items to the benefit of other NBIfAFG departments. For further information, visit our Web pages

2 162 Technical Infrastructure Projects: Laser calibration system for the ALICE Time Projection Chamber ALICE is an experiment to study relativistic heavy ion collisions at the future LHC collider at CERN with collision energies up to 6 TeV per nucleon. Technical Infrastructure group members participate with the HEHI group in two projects within the ALICE collaboration. Firstly, we are building a calibration system for the large cylindrical Time Projection Chamber (TPC) that will be the central tracking detector of ALICE. The system will generate up to 336 laser beams of each 1 mm diameter throughout the gas filled volume of the TPC. Each beam should be powerful enough to ionize the gas and simulate a charged particle track. For this purpose we have bought a powerful 266 nm pulsed Nd:YAG laser which initially is being used here to design the final mechanics and optics and later will be part of the set-up at CERN. We have inserted our micro-mirror assemblies into the 88 m 3 big TPC field cage at CERN and final design and production of he remaining system is well advanced. Figure 1 shows photos taking at CERN during the assembly and installation. N. Lindegaard, B. Svane Nielsen, E. Kaimer Olsen, J. Sørensen and J. Westergaard with the HEHI group (I.G. Bearden, H. Bøggild, J.J. Gaardhøje) Trigger and Timing Control (TTC) front-end electronics for ATLAS The future LHC proton-proton collider at CERN will have events every 25 ns. With the physical size of detectors, we will have detections from several bunch crossings at the same time. Synchronizing numerous electronics systems located in the detector caverns and underground electronics halls to the correct bunch crossing will require a quite elaborate distribution system for the transmission of Timing, Trigger and Control signals (TTC). NBI participates in a collaboration with CERN to design and manufacture a common TTC module for the TRT detector in the ATLAS experiment. In 2003, the TTC02 design was ending. NBI had responsibility for the printed circuit board (PCB) layout and manufacturing. The 12 layer PCB measures mm 2, and is equipped with advanced Field Programmable Gate Arrays (FPGAs) and fast electronics. Figure 2 shows a photograph of the prototype board. H. Bertelsen, F. Hansen and A. Lindahl with the HEP group (M. Dam, J. Dines Hansen, J. Renner Hansen, P. Hansen, B.S. Nilsson)

3 Technical Infrastructure 163 Figure 1: Working inside the ALICE TPC detector. The 88 m 3 detector volume will be illuminated with 336 tracks generated by thin laser rays. The laser tracks are simultaneous and reproducible and will be used for detailed calibration of the detector before and during the experiment. The photo was taking during installation work in clean room conditions. Also shown is a photograph from the gluing phase, where a green laser was used for alignment control. Figure 2: Photograph of the prototype TTC02 board for ATLAS.

4 164 Technical Infrastructure Test of front end electronic boards for the ATLAS TRT detector In our electronics lab, we have set up to do burn-in and testing of DTMROC electronics boards, ASDBLR boards and approximately 400 Barrel boards. All sets are final production series to be used in the ATLAS TRT detector, and the testing is a contribution of the HEP group to this experiment. The test is being preformed in 4 steps: 1) A visual inspection with a magnifying glass. 2) A current measurement for +3V, +2.5V and -3V, with and without the 40 MHz clock connected to the DTMROC boards. 3) A 14 days burn-in of 12 (8 DTMROC boards and 24 ASDBLR boards). A 14 days burn-in of 12 8 Barrel boards. 4) A final functionality test of all boards. Figure 3 shows a photograph of part of the setup in our lab. H. Bertelsen, F. Hansen and A. Lindahl with the HEP group (M. Dam, J. Dines Hansen, J. Renner Hansen, P. Hansen, B.S. Nilsson) Figure 3: Photograph of part of the electronics test setup for the ATLAS TRT.

5 Technical Infrastructure 165 Forward Si multiplicity detectors for ALICE (FMD) Another NBI project in the ALICE experiment is a silicon strip detector system to measure particle multiplicities in the forward scattering regions. A system of five ringshaped detectors with over 50,000 strips and electronics channels achieved a major milestone in 2004 by finalising a Technical Design Report. Many details of the design is now frozen and steps have been taken towards a full prototype detector. The active silicon strip sensors will be made by Hamamatsu Photonics in Japan from state of the art 6 inch diameter, 300 µm wafer technology. The electronics chain will use highly integrated low noise preamplifier Viking chips produced in a radiation hard version by IDEAS A/S in Norway and a high performance Analog-to-Digital- Converter, ALTRO, developed as a collaboration between the ALICE experiment and ST Microelectronics. The FMD Digitizer electronics module which will be the heart of the data read-out, is currently being designed at NBI. Most of the technical work for the FMD detector system is foreseen to be done at NBI. Figure 4 shows a drawing of the layout of the five detector rings within the central volume of ALICE. Also shown is the module assembly of a silicon sensor and an electric circuit board with pitch adapters, preamplifier chips and connectors. At the time of writing (April 2005), the first full module of this type has been constructed and is being tested with radioactive sources and cosmic rays. H. Bertelsen, J. Cali Hansen, B. Svane Nielsen, E. Kaimer Olsen, B. Rasmussen and J. Westergaard with the HEHI group (I.G. Bearden, H. Bøggild, C.H. Christensen, J.J. Gaardhøje, K. Gulbrandsen) Installation and maintenance of PC s and other computer equipment Service of personal computer equipment (PC s, monitors, printers and other peripherals) is an important and large part of the group engagement. Hardware and software installations are maintained for a number of Microsoft Windows systems. Much of the hardware and system software for all these systems is maintained by the group. H. Bertelsen, F. Ferrall, F. Hansen, J. Cali Hansen, A. Lindahl and Jette Sørensen with M. Lund, L. Mathiesen and B.S. Nilsson

6 166 Technical Infrastructure Figure 4: Three-dimensional drawing of the five FMD ring detectors as they will be placed in the central volume of the ALICE detector at LHC. Each ring is assembled out of wedges of silicon strip sensors fabricated from 150 mm diameter and 300 µm thick wafers. The bottom pictures shows a wedge module consisting of a sensor and a printed circuit board with the necessary electrical connections. The full system consists of five rings with over 50,000 detector channels.

7 Technical Infrastructure 167 LabVIEW based data acquisition and control system Digital data acquisition and controls have with the advent of modern electronics become an integral part of any experimental physics setup. For most of the tasks that can be foreseen at NBI, including equipment tests and student laboratory courses, a system based on plug-in cards in a standard PC and easy programming tools seems the best solution. LabVIEW from National Instruments is a graphical programming tool with drivers for plug-in cards, structured programming and easy analysis and presentation of data. It is currently in active use in the quantum optics and biophysics labs, in the chaos group, the ALICE laser lab and silicon strip test setup as well as in a number of student projects. It is also the basis of the ongoing ATLAS electronics testing. This year saw a strengthened use of the LabVIEW program at NBI in a collaboration between the Infrastructure group, the first year laboratory courses and the Quantop, biophysics, chaos, HEP and HEHI groups. H. Bertelsen, F. Hansen, A. Lindahl, B. Svane Nielsen, B. Rasmussen and J. Westergaard with M. Dam, M. Levinsen, J. Müller, L. Oddershede and G. Sletten Ge detectors and electronics for the Nordball detector pool After the dismantling of the Nordball detector at the Tandem Accelerator Laboratory, the fully functional Germanium detectors and their associated electronics form a pool for use by the Nordball collaborating institutes. Most of the detectors have been dispatched for use in other laboratories, mostly in the Nordic countries, but some have passed through the test and maintenance facility here. Two Ge detectors are set up in our lab together with electronics and a new liquid nitrogen system. It will remain as a setup for student projects where coincidence measurements of pulse height spectra from radioactive sources can be measured and analysed using the LabVIEW Multichannel Analyser program mentioned above. B. Rasmussen and J. Westergaard with the Nuclear Structure group (G. Hagemann, B. Herskind, G. Sletten)

8 168 Technical Infrastructure Nuclear target production The target laboratory is a highly specialised and rather unique facility with experience and equipment to produce targets for nuclear physics experiments. We have in storage a large number of rare isotopes, some of which require permanent vacuum conditions in order not to degrade. Targets usually consist of thin foils of a single isotope or single element, in some cases supported on thin gold foils or other backings. The produced targets are mostly for use by the Nuclear Structure group and its international collaborators in various nuclear physics experiments abroad. N. Lindegaard, Jens Sørensen, Jette Sørensen and J. Westergaard with the Nuclear Structure group (G. Hagemann, B. Herskind, G. Sletten) Multimedia and poster facilities A video conferencing facility is set up in Ma11 to allow smaller meetings with remote sites or one-way distribution of lecture style meetings through telephone connections. Digital photo processing jobs are handled, and we have facilities for formatting and printing of posters. A large format image printer is mainly used for mechanical drawings, but posters and other plots can be printed up to A1 format. We also have facilities for video recording of lectures and loading of the recordings on the Web. J. Engelhardt, F. Ferrall, F. Hansen, J. Cali Hansen, A. Lindahl and E. Kaimer Olsen with A. Wäänänen Student projects The education of students at all levels from the first year lab course to M.Sc. and PhD projects requires qualified technical assistance. These at times demanding tasks are a welcomed chance to interact closely with experimenters and students. The re-structured first year lab courses continue to be a source of construction and repair tasks for the mechanical workshop, often requested on short notice. Similarly, electronics and electro-mechanical tasks include the design of a number of smaller electronic circuits and repair of older equipment. The extensive use of the LabVIEW programming environment in the student exercises is a recent step toward a renewal of the student facilities with respect to the use of computers. Help with chemicals and chemistry equipment is serviced from the target laboratory. The participating in the High Energy experimental practice education involves a setup with proportional chambers and drift chambers together with a multi-channel acquisition system. The experimental setup measures the decay of cosmic muons into electrons. We are currently in the process of carrying out maintenance and

9 Technical Infrastructure 169 development of the equipment and its software. A nuclear physics experimental setup consists of two germanium detectors for coincident gamma ray detection and an acquisition system based on a LabVIEW Multi Channel Analyser. Also, a new radon concentration measurement setup, based on the radon alpha radioactivity, was made available to students. L. Antvorskov, H. Bertelsen, J. Engelhardt, F. Ferrall, E. Grønbæk, J. Cali Hansen, F. Hansen, A. Lindahl, N. Lindegaard, B. Svane Nielsen, E. Kaimer Olsen, E. Petersen, B. Rasmussen, Jens Sørensen, Jette Sørensen and J. Westergaard with J. Bondorf, H. Bøggild, C. Ellegaard, J. Dines Hansen, M. Levinsen, G. Sletten and many others Building installations Various electrical and mechanical installations in the buildings were carried out by the group, in particular in connection with the chaos and biophysics experiments, the lecture rooms and the student facilities. L. Antvorskov, J. Engelhardt, F, Ferrall, E. Grønbæk, J. Cali Hansen, N. Lindegaard, E. Petersen, Jens Sørensen and J. Westergaard