Preprint typeset in JINST style - HYPER VERSION

Electronics for Particle Physics in Austria

Manfred Jeitlera∗

aInstitute of High Energy Physics of the Austrian Academy of Sciences,Nikolsdorfergasse 18, 1050 Vienna, AustriaE-mail: manfred.jeitler@cern.ch

ABSTRACT: In Austria a number of scientific institutes affiliated with the Academy of Sciencesor with universities are active in the fields of particle physics and astro-particle physics. Someof these institutes engage actively in hardware developments for particle detectors and associatedelectronics. There are also a number of commercial electronics companies with dedicated devel-opment projects for particle physics. Moreover, construction is under way for a medical center foraccelerator-based ion therapy.

KEYWORDS: High Energy Physics, Particle Physics, Electronics, Ion therapy, Austria.

∗Corresponding author.

Contents

1. Austrian scientific institutions active in particle physics 11.1 Institute of High Energy Physics (HEPHY) of the Austrian Academy of Sciences 1

1.1.1 Semiconductor detectors and readout electronics 21.1.2 Trigger electronics 2

1.2 Stefan Meyer Institute for Subatomic Physics (SMI) of the Austrian Academy ofSciences 3

1.3 Vienna Environmental Research Accelerator (VERA) of the University of Vienna 41.4 Particle and Astroparticle group of the University of Innsbruck 51.5 Institute of Atomic and Subatomic Physics (Atominstitut) of the Vienna University

of Technology 5

2. Ion-therapy center MedAustron 6

3. Austrian electronics companies active in particle physics 63.1 Cividec Instrumentation 63.2 Kapsch 6

4. Conclusions 7

1. Austrian scientific institutions active in particle physics

In Austria, particle physics is studied by two Vienna-based institutes of the Austrian Academy ofSciences as well as by institutes affiliated with the University of Vienna, the Vienna University ofTechnology and the University of Innsbruck.

1.1 Institute of High Energy Physics (HEPHY) of the Austrian Academy of Sciences

The Institute of High Energy Physics in Vienna participates in experiments at CERN in Geneva aswell as in the Belle experiment at KEK-B in Japan. For these experiments the institute has devel-oped and built trigger and readout electronics as well as detectors (in recent years mostly silicondetectors). Apart from the concrete involvement in these experiments the institute is also active insilicon detector development in general, in the development of tracking algorithms, in studies forthe planned International Linear Collider and in theory (Supersymmetry phenomenology).

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1.1.1 Semiconductor detectors and readout electronics

HEPHY has a special semiconductor lab with a clean room allowing for detector module assembly,wire bonding and comprehensive tests [1]. Here, several thousand silicon detectors were charac-terized and 650 endcap modules were built for the silicon strip tracker of the CMS experiment.Moreover, about 500 CMS tracker modules of different types were repaired. Also, the group coor-dinated the whole production project for the CMS tracker endcap modules, involving 14 differentinstitutes, which built about 7000 modules in total. Since the CMS tracker was completed, thegroup has been working on upgrade studies for this detector and in the R&D on double sidedsilicon detectors for the Belle II experiment [2].

Figure 1. Silicon detector modules designed and built by the Institute of High Energy Physics.

For the silicon pixel detector of CMS the institute designed and built the readout system [3],which receives the analog optical signals from the detector cavern, digitizes, synchronizes andformats the data and sends them via serial links (“S-links”) to the CMS data acquisition system (seeFigure 2). Now the pixel detector’s upgrade is already under work [4], in the course of which theanalog optical links will be replaced by serialized digital links. The resulting higher data transferdensity will allow to accommodate more readout channels using the existing infrastructure (suchas optical fibers and crates).

The group has also built the readout electronics for the silicon vertex detector of the Belleexperiment in Japan and is now designing the upgrade of this detector [5]. Belle-II will use a newcentral pixel layer using DEPFETs, and the strip layers will be extended to a radius of 14 cm.Each double-sided sensor will be read out individually to allow for a good signal-to-noise ratio. Tomake this possible, a chip-on-sensor approach is being used. The institute is developing not onlythe detectors but also the complete modules, readout electronics, mechanics and the CO2-coolingsystem.

1.1.2 Trigger electronics

Another group of the Institute of High Energy Physics has designed and built major parts of theCMS hardware trigger (the “Level-1 trigger”): the “Drift Tube Track Finder” [6], the “Global MuonTrigger” and the “Global Trigger” [7] were all developed here (see Figure 3). The LHC experimentstake data at the bunch crossing rate of 40 MHz, and for each bunch crossing the Level-1 triggermust calculate a decision. Trigger primitives are mostly delivered from the electromagnetic and

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hadronic calorimeters and from the three muon systems (drift tubes, cathode strip chambers andresistive plate chambers) as well as from a few other systems.

While trigger primitives from upstream systems are processed in special ASICs, the digitalelectronics built at the Institute is completely FPGA based. This allows keeping a high level offlexibility, and in fact, since LHC went into operation the trigger menu firmware has been updatedfrequently to keep track of the rising luminosity and changing conditions.

Figure 2. Front End Detector module for thePixel detector of the CMS experiment at the LHC,designed and built by the Institute of High EnergyPhysics.

Figure 3. The Global Trigger and the Global MuonTrigger of the CMS experiment at the LHC, de-signed and built by the Institute of High EnergyPhysics.

While the present electronics is housed in 9U-VME crates the trigger group is now migratingthe systems to the more compact µTCA platform in the course of the experiment’s upgrade project,which will allow taking data at higher intensities and with improved performance. This new versionof the electronics is scheduled to be deployed in 2017. Increasing use of standardized, centrallybuilt modules is planned, and the engineering work will be more and more in the field of firmware.

1.2 Stefan Meyer Institute for Subatomic Physics (SMI) of the Austrian Academy of Sciences

This second particle physics institute of the Academy of Sciences is housed in the building of the“Radiuminstitut”, the first institute in the world established as a dedicated institution for scientificresearch in the field of radioactivity. This institute specializes in experiments of somewhat smallerscale than HEPHY and has been active in a large number of experiments at the “muon factory”of the Paul Scherrer Institute (PSI, Switzerland), the “φ factory” DAΦNE at Frascati, Italy, exper-iments at the Antiproton Decelerator at CERN (ATRAP and ASACUSA), and the FAIR facilitywhich is being built at GSI in Darmstadt, Germany.

On the hardware side SMI has been making important contributions in particular for cryogenictarget vessels but is also very active in building detectors and the associated electronics. Theinstitute – at that time still called “Institute of Medium Energy Physics (IMEP)” – participatedin some of the first experiments where CCDs (Charged Coupled Devices) were used as X-raydetectors to study so-called “exotic” atoms, where an electron is replaced by some other particle,such as a muon (µ−) or a K-meson (K−). Later on, this detector type was replaced by Silicon DriftDetectors (SDD). Such a detector, which has a very good energy resolution and significantly better

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time resolution than CCDs, is presently being used in the SIDDHARTA experiment at DAΦNE [8].While the various components were produced in other laboratories, the detector design and the finalassembly and testing of the detector were carried out at SMI.

Figure 4. A silicon drift detector from Stefan Meyer Institute (left) and the energy resolution achieved bythis device (right).

For its involvement in the PANDA experiment at FAIR, the Institute is currently building aTime Projection Chamber (TPC) where the pad readout is effected by GEMs (Gas Electron Mul-tipliers) with a total of about 10 000 readout channels. Another detector type used by SMI is the“Silicon Photomultiplier (SiPM)” or “Multi-Pixel Photon Counter (MPPC)”, which is a newly de-veloped photodetector with excellent photon counting capability. It has also many other attractivefeatures such as small size, high gain, low operating voltage and power consumption, and can beoperated in magnetic fields. A number of such devices is available on the market and SMI is car-rying out work to validate them and find out which of them are the most suited for particle physicsexperiments [9].

1.3 Vienna Environmental Research Accelerator (VERA) of the University of Vienna

Figure 5. The ice-age man (dubbed “Ötzi”) whowas accurately dated by using the 14C-method inthe accelerator mass spectrometer of the VERAfacility.

Figure 6. The tandem accelerator of the VERA fa-cility.

VERA is a tandem accelerator dedicated to accelerator mass spectrometry [10]. It allows mea-suring long-lived radioisotopes by atom counting rather than by decay counting and is of particular

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importance for improving the sensitivity of the 14C dating method, allowing to use samples of mil-ligrams rather than grams and doing the measurement during less than an hour rather than overseveral days.

The method has, among others, been used for accurately dating the remains of the body of astone-age man found in a glacier on the Austrian-Italian border, the famous “Ötzi”.

1.4 Particle and Astroparticle group of the University of Innsbruck

Apart from a smaller group participating in the ATLAS experiment at the LHC, the particle physicsactivities of the University of Innsbruck are mostly dedicated to astro-particle physics [11]. TheUniversity of Innsbruck has quite a tradition in this field: Victor Franz Hess, who discovered cosmicradiation in 1912 and was awarded the Nobel prize for this discovery in 1936, was professor ofphysics in Innsbruck. He established an observatory for cosmic radiation on the nearby Hafelekarmountain, which still exists as a neutron and muon monitor and is being modernized at the moment.

Currently, this physics institute is involved in the Cherenkov telescope array HESS in Namibiaand in the gamma-ray satellite experiment FERMI. While at the moment the group is concentratingon data analysis there are plans to also work in hardware development in the future.

Figure 7. The neutron and muon monitoring sta-tion of the University of Innsbruck on Hafelekarmountain.

Figure 8. The TRIGA Mark II reactor of the Insti-tute of Atomic and Subatomic Physics in Vienna.

1.5 Institute of Atomic and Subatomic Physics (Atominstitut) of the Vienna University ofTechnology

This institute was originally founded as an inter-university institution but belongs now to the Vi-enna University of Technology [12]. The original research areas were atomic, nuclear and reactorphysics, radiation physics and radiochemistry, and related subjects. Now, the institute is also veryactive in the field of quantum physics and quantum optics as well as low-temperature physics andsuperconductivity.

The Institute also runs Austria’s only research reactor (of the TRIGA Mark II type, figure 8).This is highly useful also for other researchers in various fields. So, engineers from the Institute ofHigh Energy Physics (see section (1.1 above) use the reactor for determining the radiation hardnessof new types of silicon detectors.

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2. Ion-therapy center MedAustron

The ion-therapy center MedAustron [13], which is currently under construction near the city ofWiener Neustadt in the province of Lower Austria (about 50 km from Vienna), will be used bothfor clinical therapy of cancer patients and for scientific research. A synchrotron-based acceleratorcomplex will be used to accelerate protons up to 800 MeV, and carbon ions (12C6+) up to 400 MeVper nucleon. A pulse-to-pulse modulation system will allow to accurately choose the dose to bedelivered to patients. At the same time, test beams will be available for detector development forparticle physics. After several years of preparation, construction started early this year (2011) andthe center is scheduled to treat first patients in 2015.

Figure 9. The contruction site of the MedAustron ion therapy center (left) and the beam layout of the facility(right).

3. Austrian electronics companies active in particle physics

A number of Austrian electronics companies are cooperating with scientific institutions in the fieldof particle physics, such as Austriamicrosystems company [14] in Unterpremstätten, Styria, In-fineon Technologies Austria AG [15] in Villach, Carinthia, and NXP Semiconductors AustriaGmbH [16] in Gratkorn, Styria. Two companies that have already had a particularly importantimpact in the field are described below in somewhat more detail.

3.1 Cividec Instrumentation

This Vienna-based company [17] provides beam instrumentation for particle accelerators basedon diamond detectors with fast electronics and digital on-line processing and readout. The com-pany has delivered beam loss monitors for LHC (CERN), beam position monitors for XFEL (FreeElectron Laser, Hamburg, Germany), particle counters for Fermilab (Chicago) and beam profilemonitors for hadron therapy projects. The diamond detectors have sizes of up to 100 mm × 100mm and thicknesses down to 50 µm. The associated electronics includes 2-GHz current amplifiersand 100-MHz charge amplifiers.

3.2 Kapsch

The Vienna-based company [18] delivered over 25 000 optohybrids of various types for the CMSexperiment. These are tiny converters from electrical to optical signals located in the detector front-

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Figure 10. A diamond detector built by CividecInstrumentation and used for beam monitoring atthe LHC.

Figure 11. One of many thousands of optohybridsbuilt by Kapsch and used for the tracking detectorof the CMS experiment at the LHC.

end. Out of these, there were over 13 000 analog optohybrids for the strip tracker, 300 analog pixeloptohybrids for the pixel detector, 2000 digital optohybrids for the tracker in general, and about10 000 gigabit optical links for the electromagnetic calorimeter of CMS. The analog optohybridsfor both strip detectors and pixels were developed by and manufactured upon order of HEPHY(cf. 1.1). The delivery volume was about 1 million CHF. This is the largest single participation ofan Austrian company in the electronics at the LHC, and Kapsch received the CMS Gold Award in2007.

4. Conclusions

Compared to its small size, Austria makes a large contribution to, and is very active in particlephysics and in electronics developments for this field. Austrian scientific institutes participate inaccelerator experiments and cosmic ray experiments all over the world and commercial companiesare developing and building electronics for these projects. The construction of an accelerator forion cancer therapy and scientific research is giving further momentum to the field.

Acknowledgments

In this overview the work of many different scientific institutions and commercial companies hasbeen presented and I gratefully acknowledge the help of colleagues from academia and industrywho generously supplied me with information and graphical material.

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[11] http://www.uibk.ac.at/astro

[12] http://www.ati.ac.at/index.php?id=startseite&L=1

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[14] http://www.austriamicrosystems.com/

[15] http://www.infineon.com/cms/regional-pages/infineon-austria/index.html

[16] http://www.nxp.com/about/sales-offices-distributors/general-terms-and-conditions-of-purchase/austria.html

[17] http://www.cividec.at

[18] http://www.kapsch.at

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