Applied Physics Laboratory (APL) at the Faculty of Electronic Engineering at University of Nis as a potential centre of excellence

Goran S. Ristic

www.elfak.ni.ac.rs/apl/

Who are weWho are we Research in applied physics at the Faculty of

Electronic Engineering started more than 35 years ago in the investigation of the processes in ionized gases at low pressure.

The firstly formed laboratory was a Laboratory of Ionized Gases.

Later, at the beginning of 90’s the research was extended in the radiation effects on metal-oxide-semiconductor field effects transistors (MOSFETs), in the aim of their radiation hardening and radiation softening.

APL research includes the different fields: Semiconductor physics, Solid state physics, Physics of ionized gases, Radiation physics, Physics in medical diagnostics, and so on In 2007, the name was changed in Applied

Physics Laboratory (APL). APL has valuable collaboration with many

institutions and laboratories from our country and world-wide countries.

The laboratory contains seven people, three professors:Prof. Goran Ristic, Ph.D.Prof. Momcilo Pejovic, Ph.D.Prof. Jugoslav Karamarkovic, Ph.D.

and four research & teaching assistants:Milic Pejovic, Ph.D.Sanja Aleksic, M.Sc.Nikola Nesic, M.Sc.Emilija Zivanovic, M.Sc.

and their research includes several different areas of applied physics:

the reliability of metal-oxide-semiconductor (MOS) transistors, including the dosimetric p-channel MOS transistors (the second name is RADFETs),

the electrical discharge and recombination processes in the afterglow periods in gases,

digital X-ray imaging (in collaboration with Department of Medical Imaging, University of Toronto)

physical optics ray tracing modelling of terahertz waves (in collaboration with German Aerospace Center)

Many investigation areas, relatively small people number!

One of our characteristics is just our possibility to simultaneously work in various, often very different fields of applied physics

Two main research fields:1. Reliability of MOS Devices- the effects of ionising radiation and post-irradiation

annealing on commercial MOS transistors in the aim of their radiation hardness improvement,

- radiation and post-irradiation effects on specially designed pMOS dosimetric transistors (RADFETs), in the aim of the obtaining of very sensitive devices to ionising radiation that could be used as radiation dosimeters,

- the effects of high field electric stress and post-electrical stress on commercial MOS devices in the aim of their resistance to electric stress improvement.

2. Gas Discharges at Low Pressures- The investigations of non-equilibrium in low

temperature plasma, considering the processes which occur during the pre-breakdown, breakdown and afterglow periods,

- Developing of the qualitative method for the separation of individual particles responsible for the electrical breakdown,

- as well as the method for the breakdown voltage statistical estimation.

- The investigation of possibility of using electrical breakdown mechanisms in gas tube radiation detector

During the past 35 years more than 100 papers have been published in peer-reviewed international journals from SCI list (www.elfak.ni.ac.rs/apl/research.php) in more research areas:

gas discharge at low pressures (61 papers), radiation and post-radiation effects on MOS transistors

(32 papers, but 9 of them are relating to pMOS dosimeters),

high electrical field stress and post-stress effects on MOS transistors (6 papers),

digital X-ray imaging (2 papers quoted even 37 times), 1 papers in terahertz optics, and so on.

PublicationsPublications

Journal Number of articles

Impact factor

Journal of Physics D: Applied PhysicsPhysics of PlasmasIEEE Trans. Nuclear ScienceIEEE Transaction of Plasma ScienceSolid-State ElectronicsElectronic Letters Physica Status Solidi (a)Applied Physics Letters Review of Scientific InstrumentsApplied Surface ScienceJapanese Journal of Applied PhysicsJournal of Applied PhysicsJournal of Non-Crystalline Solid Medical PhysicsSensors and Actuators: A. Physical

2475544433332222

2.1042.4271.5181.4471.4221.1401.2053.7261.7381.5761.3092.2011.4493.8711.724

The paper qualities have been very important, and only a few papers have been published in the journals with impact factor less than 1.

Even 77 papers have been published in the international journals in the last 15 years with the average impact factor of 1.86.

The papers published in APL are quoted more than 200 times. All these research areas are current today.

APL`s staff is relatively small, but pretty productive

Laboratory researchers currently perform national fundamental research projects supported by the Ministry of Science of the Republic of Serbia

2006-2010  Processes in pre-breakdown and afterglow periods of electrical breakdown in gases at low pressures and defects in semiconductor materials induces by ionizing radiation and electrical field

2002-2005 Electrical breakdown in gases at low pressures and some characteristics of semiconductor materials

1996-2000 Physical processes in ionized gases and materials in condensate state

1995-1997 Semiconductor micro-dosimeters for gamma and X-ray radiations

1993-1995 Development of radiation sensor

ProjectsProjects

In the middle of 2008, the FP7 – REGPOT-2007-3 projects, entitled “Joint research on various types of radiation dosimeters (RADDOS)“ funded by European Commission, started.

The idea was to continue the research in pMOS dosimeters, together with our partners from Tyndall Institute, Cork, Republic of Ireland, and Josef Stefan Institute (JSI), Ljubljana, Slovenia.

European Commission warded us by RADDOS grant since they recognized APL as a potential center of excellence that is, with some financial support, capable to be included in the future EU projects in radiation dosimeters.

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V (gate)G

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READER CIRCUIT(RC)

SKIN

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Sensor

RADIATION

TUMOR

One of purpose of pMOS dosimeters is in the radiotherapy

The main pMOS dosimeter advantages, in comparison with other dosimetric systems:

immediate, non-destructive read out of dosimetric information,

extremely small size of the sensor element, the ability to permanently store the absorbed dose, wide dose range, very low power consumption, compatibility with microprocessors, competitive price (especially if cost of the read out

system is taken into account). The disadvantages are: need for calibration in different radiation fields, relatively low resolution (starting from about 1 rad) and nonreusability.

Tyndall Institute has a small line for MOS device productions, and it is one of the most famous world places for pMOS dosimetric transistor productions.

JSI is involved in ATLAS experiment at CERN incorporating the pMOS transistors in the damage monitoring in electronics and detectors.

Our FP-7 partnersOur FP-7 partners

JOEL 6000F3 e-beam equipment in use in theclean room

state-of-the-art equipment in use in the clean room

ATLAS experimentLHC Probing the physics at 1 TeV scale(search for Higgs, supersymetry ...)•Colliding p beams with 7 TeV•Bunches colliding every 25 ns (23 pp collisions/bunch)•LHC collider put into the LEP tunnel

ATLAS collaboration•~2400 scientists•169 institutions•34 countries

•20 years developmentInvestment ~550 MEUR

START of collision: autum 2008

Within RADDOS, APL has been investigating the other types of radiation dosimeters, as radioluminescent (RL), thermoluminescent (TL), and optically stimulated luminescent (OSL) dosimeters.

In addition, APL has been developing and designing the pMOS, RL, TL and OSL dosimeter readers, and they will be realized in our laboratory.

The budget of RADDOS project for APL of 371 611 EUR[1] for 3 years seems modestly, since requested budget could be up to 1 000 000 EUR, but we have a problem with the number of people.

Namely, only a few people in APL are working on pMOS dosimeters, but a lot of activities within RADDOS have to be performed.

[1] A budget of 529 971 EUR for all participants was asked and approved.

For instance, 31 months in total should be spent in partner institutions (total budget of 82 000 EUR) and 4 months in various centre of EU (16 000 EUR), as well as to participate in 10 international conferences (17 500 EUR).

The largest fund of 115 000 EUR is for the equipment, and 80 000 EUR for the recruitment of two young researchers for the period of three years (gross salary of 900 EUR per researcher).

The value of equipment is more than 100 000 EUR Most of equipment has been bought through the

RADDOS project

EquipmentEquipment

Keithley Semiconductor Characterization System with Flat Panel Display (65 000 EUR)

Ultra Low Current, 8 x 12 High Speed Switching Matrix (16 000 EUR)

Dual-channel Low Current Source Meters (15 000 EUR)

Current Source Meters (5 000 EUR each)

Tektronix Digital Oscilloscope 350 MHz, 2.5 GS/s (5 000 EUR)

Hewlett Packard Pulse/Function Generator 50 MHz (5 000 EUR)

Vacuumbrand Vacuum Pumping System (10 000 EUR)

Spectrometer for 200 – 1100 nm (5 000 EUR)

50 000 EUR for equipment purchasing left We have planed to buy the equipment for RL, TL

and OSL dosimeters We hope these dosimeters will be producing in our

lab, since they do not need a strictly controlled conditions (e.g. small lab of a few people in Vinca had produced TL dosimeters – they are small tablets) ,

as well as to develop the cheap readers for those TL and OSL dosimeters

THANK YOU VERY MUCH FOR YOUR ATTENTION!THANK YOU VERY MUCH FOR YOUR ATTENTION!

www.elfak.ni.ac.rs/apl/

3 professors, 1 PhD assistant, 3 research assistants, and 2 young researchers funded by RADDOS, are working in APL

the research assistants are in the same time the teaching assistants

Many investigation areas, small people number APL has valuably collaboration with many

institutions and laboratories from our country and world-wide countries.

APL staffAPL staff