Scientific Projects ( STSMs )


 Institut Lumière Matière, Villeurbanne

 Department of Optical materials, Institute of Physics, Prague

Duration: 33 days (15/06/2015 to 17/07/2015)

Doping effect on the timing performances of scintillator

The main goal of this STSM is to work on the doping effect on the timing performances of scintillator. On one hand FZU is well experienced in the physics associated to the impurities effects in the energy transfer process. On the other hand the trainee, Gael Patton is preparing a PhD on the role of defect on the memory effects in scintillating materials. Sharing experiences will be a good opportunity for the 2 research groups (ILM and FZU)


 Università Politecnica delle Marche, Ancona

 European Organisation for Nuclear Research (CERN)

Duration: 2.5 months (15/07/2015 to 01/10/2015 )

Verify the influence of the strain/stress on the functional optical properties of the crystal

The activity aims to verify the influence of the strain/stress on the functional optical properties of the crystal in order to evaluate if the stress state has an effect on the light transport. If this effect is verified, the activity will determine a correlation between stress and optical performances of the crystal in order to characterize this phenomenon.


 Italian Institute of Technology, Genova

 European Organisation for Nuclear Research (CERN)

Duration: 1 month (01/08/2015 to 31/08/2015)

Use of colloidal nanocrystals (NCs) to provide sub-100ps response to high energy excitation

The feasibility of using colloidal nanocrystals (NCs) to provide sub-100 picosecond response to high energy excitation will be investigated. Toward this end, the photo-response of shape- and composition-controlled NCs including core/shell quantum dots (QDs) and 2-dimensional nanoplates (NPLs) under high energy excitation will be measured.


 Technological Educational Institute of Athens

 Division of Biomedical imaging, University of Leeds

Duration: 5 months (01/09/2015 to 31/01/2016)

Implementation of TOF reconstruction in STIR software

STIR is an open source image reconstruction toolkit, well validated by the scientific community. It is feature-rich and versatile but it doesn’t include the option to reconstruct with TOF information. The purpose of this STSM is the implementation of TOF reconstruction algorithm which will distribute free in a future version of STIR.The distribution of this feature is going to help numerous researchers in their studies and provide a common background for results sharing.


 CIEMAT, Madrid

 European Organisation for Nuclear Research (CERN)

Duration: 5 days (24/08/2015 to 28/08/2015)

Precise timing measurements of the FlexToT v2 ASIC

Performing precise timing measurements of the FlexToT v2 ASIC using the characterization setup at CERN based on the NINO ASIC, taking advantage of equipments which are not available at the home institution nor at national collaborators, such as co-doped LSO:Ce,Ca scintillators and HPTDCs. In particular, the coincidence time resolution (CTR) and the single photon time resolution (SPTR) will be evaluated under different conditions, aiming at precisely characterizing the best possible timing performance of the lexToTv2 ASIC for TOF-PET applications.


 PETsys Electronics, SA, Lisboa Science and Technology Park

 Dept. Nuclear Medicine, Laarbeeklaan

Duration: 3 weeks (24/11/2015 to 15/12/2015)

Fast TOF reonstruction algorithm

Learn the new techniques in tomographic image reconstruction to develop a fast TOF PET image reconstruction algorithm for a new PEM scanner and to speed up the calculation without the need for such extensive hardware.


 Research Institute for Nuclear Problems, Minsk

 Semiconductor Physics Department, Vilnius University

Duration: 5 days (05/10/2015 to 09/10/2015)

Study of the possibility to measure rise time of scintillator by nonlinear optics methods

Timing become crucial feature of detecting systems to be applied in collider experiments. Particularly, it is important for experiments at LHC with high luminosity. Lead tungstate scintillation material is used at two experiments at LHC. So it is important to understand a limit of this scintillation material for fast timing. It is suggested that rise time of scintillation in a low light yield self-activated scintillator is one of the limiting factors for a very fast timing. However, no reliable data of the rise time in PWO are available for the moment. We expect that it is faster in PWO than in a doped scintillator. So, essential of the work plan is to examine different possibilities to measure rise time in the range 20-80 ps . The brainstorming with Colleagues from Vilnius University is also in the plan.


 Institute of Physics, University of Tartu, Tartu

 European Organisation for Nuclear Research (CERN)

Duration: 10 days (24/01/2016 to 06/02/2016)

Measurement of time and spectral properties of IBL in several popular scintillating materials utilizing pulsed low-density x-ray luminescence setup available in CERN

Intraband luminescence (IBL) is one of the candidate processes for extremely fast scintillators. This prompt (about 1 ps decay time) emission with a relatively low efficiency (10-5–10-3 eV/eV) is connected with the radiative transitions of hot electrons (e-IBL) or hot holes (h-IBL) between the levels of the conduction or valence band of a crystal, respectively. Despite a low efficiency, this process can be still considered for TOF-PET to provide a time marker for the event. Our recent studies have been aimed at finding the materials with the highest IBL yield and proposing the ways IBL could be utilized for fast timing. All our spectral data were obtained so far at a single experimental setup in Tartu utilizing a high-density electron beam excitation. These data may suffer from the influence of surface effects and needs to be verified using a different experimental technique implementing an excitation method more similar to that in PET. The proposed working plan for the STSM contains the measurement of time and spectral properties of IBL in several popular scintillating materials utilizing pulsed low-density x-ray luminescence setup available in CERN.


 European Organisation for Nuclear Research (CERN)

 LIP, Lisboa

Duration: 5 days (10/11/2015 to 15/11/2015)

Test the TOF capability of new PET module developed in the frame of the Crystal clear collaboration for the next generation of PET using the TOF-­‐PET Asic developed by the Lisbon group

The working plan aims to test the TOF capability of new PET module developed in the frame of the Crystal clear collaboration for the next generation of PET using the TOF-­‐PET Asic developed by the Lisbon group. At CERN the module based on a 64 LYSO:Ce crystals matrix and a MPPC array (Hamamatsu) was tested using a CAEN DT5740 digitizer. The time binning of the digitizer does not allow the realization of time measurements as CTR (“Coincidence Time resolution”) but the TOF-­‐PET Asic can reach this purpose with a time binning of 50 ps. The increase of the time resolution due to the finer time binning reduce the random coincidence rate and this feature makes this kind of device more suitable in PET scanner.


 Institute of Atomic and Subatomic Particles, Vienna

 Radiation for Isotopes and Health, Delft University of Technology

Duration: 12 days (21/02/2016 to 04/03/2016)

MC simulations for ultra fast gamma detector design

The EU-project PALADIN (positron annihilation detection beyond the limits, ref. nb. 659317) aims to overcome present technological limits and pushing time resolution beyond current limits. Therefore, a new detector based on monolithic scintillation crystals combined with digital photon counter (DPC) arrays is being designed. The future detector will be incorporated in a PALS setup at the Reactor Institute at TU Delft and used for TU Delfts materials research on renewable energy. Hence, the detector performance will be investigated for application in clinical TOF-PET devices allowing to go beyond state-of-the-art spatial and temporal resolution. This short term scientific mission of approximately two weeks will mainly serve to acquire practical knowledge of the experimental set up for the researcher Florian Dachs. This will help him for his master thesis project to develop a detailed simulation using GEANT4 with the goal to investigate the characteristics of the detector system. Besides acquiring knowhow of the detector system, the problem of self triggering due to photo emission during cell recharge will be investigated experimentally and a strategy for minimizing this effect should be found during the STSM. Apart of the scientific value, the STSM will also allow to get to know the partner-team at TU Delft in person, which will strengthen the team-spirit of the collaboration.


 Research Institute for Nuclear Problems, Minsk

 Semiconductor Physics Department, Vilnius University

Duration: 5 days (10/12/2015 to 16/12/2015)

Study of potential of different techniques to measure rise time of luminescence in crystals

Recently, we started preparation of the series of experiments to measure decay time of scintillation materials by non-linear optics methods. First results are encouraging. It was already found that rise time of PWO at photo-excitation is less than 25 ps, whereas rise time of photo-luminescence of GAGG:Ce depends on wavelength of excitation. During October – November 2015 we performed a set of modeling experiments. Thickness of samples was optimized and new samples were prepared by RINP optical shop. We plan to carry on new measurements during the week from 10th of December 2015. Scheduled activity agreed with Prof. Gintautas Tamulaitis, head of he chair and dedicated laboratory.


 Institute of Neuroscience and Medicine (INM-4), Jülich

  Fondazione Bruno Kessler - FBK, Trento

Duration: 5 days (14/3/2016 to 18/3/2016)

Characterization of Linearly-Graded Silicon Photomultiplier coupled to monolithic crystals

An 8-by-8 mm² LG-SiPM prototype has been already developed by the FBK. Miniature monolithic crystals are provided by Forschungszentrum Jülich GmbH. With the existing hardware, proof-of-concept study for LG-SiPM 8-by-8 mm² coupled to monolithic scintillators based detectors can be characterized can be performed. First feasibility measurements should demonstrate the possibility to identify the x- and y-position of the scintillator event inside a monolithic 8-by-8-by-3 mm³ crystal. If x and y positions can be determined, the scintillation detector will be characterized for its spatial, energy and timing resolution. Results from simulations that have been run at the Foprschungszentrum Jülich GmbH during the year 2015 were very promising and encourage us to proceed with measurements. The measurements should take place at FBK. In advance, the measurement will be prepared in cooperation between FBK and Forschungszentrum Jülich GmbH. The total measurement time is planned for 5 days. The first day is for preparing the final measurement setup. During the second and third days, the previous prepared position algorithms will be applied to characterize the position-encoding of this detector setup. This is a necessary step for the fourth and fifth days, where the energy and timing resolution measurements are planned. Measurements of energy resolution, spatial resolution and timing resolution are planned for 3 typical positions in the plane of the entrance window (i.e. center, corner, center of border) The results of these measurements should be published in paper providing a full characterization of the new 8-by-8 mm² LG-SiPM prototype coupled to monolithic crystal. Further work to be performed after this feasibility study include a full characterization of this type of scintillation detector, the comparison of detector performances of the 8-by-8 mm² LG-SiPM between the monolithic and a pixilated detector setup. Especially the comparison of the timing resolution is an important result for FAST. If the indented scintillation detector design is feasible, it would be a very interesting detector concept for high spatial resolution and high sensitivity small animal PET inserts for simultaneous preclinical PET/MR imaging.


 NRNU MEPhI, Moscow

 KETEK GmbH, München

Duration: 22 days (20/01/2016 to 10/02/2016)

Measuring of photodetection and timing properties of the KETEK SiPMs

  1. Measuring of photodetection and timing properties of the KETEK SiPMs with different sensitive area by using of variable connection schemes in order to select of the optimum SiPM type and readout way for TOF PET application.
  2. Implementation of differentiation pulse technique for improving of SiPM+scintillator crystal timing resolution. Selection of the best fast amplifier for usage with wide bandwidth digital scope as a reference setup.
  3. Development and implementation of the dedicated algorithm for digital processing with data from single detector obtained by using wide bandwidth digital scope. Data analysis with ROOT.
  4. Selection of the fast scintillator and its geometry. Two possible candidates are LYSO and GAGG scintillator crystalls.
  5. Development of a prototype module for TOF PET application on the basis of KETEK SiPMs and PETsys TOF ASIC evaluation kit (http://www.petsyselectronics.com/web/ ) with two identical detectors’ arrays.
  6. Experimental study of the developed TOF PET module with Na-22 source.

 Institute for Neuroscience and Medicine, Jülich

  University Hospital Zurich, Zürich

Duration: 6 days (24/01/2015 to 29/01/2015)

LSO background radiation for attenuation correction (AC)

In our group, we have been working on LSO background radiation for attenuation correction (AC) and our results are quite promising [1]. Until this moment, we have applied our approach to the Siemens 3T MR-BrainPET scanner available at our research center, which does not have Time-Of-Flight (TOF) capabilities. Therefore, the transmission and emission measurement cannot be performed simultaneously, but rather sequentially. This is incompatible with clinical practice and can only be done in research facilities. In this STSM, our goal is to apply the developed approach to the GE Signa scanner [2], which has TOF capabilities. For this purpose, we will perform measurements with the LSO background for two different phantoms (cylinder phantom and head phantom) without any activity, but also with activity to evaluate the AC performance. We will also acquire MR images of these phantoms. Furthermore, we will have to convert the acquired data to a format readable by our program, perform the necessary corrections and reconstruct the data. We will perform different pre-processing of the data: random correction, sinogram compression, bin calculations and reconstruction to evaluate the best processing pipeline. We will also evaluate the acquisition time necessary for obtaining a reasonable attenuation correction map.


 Institute for Neuroscience and Medicine, Jülich

 University Hospital Zurich Klinik für Nuklearmedizin, Zürich

Duration: 6 days (24/01/2015 to 29/01/2016)

LSO background radiation for attenuation correction (AC)

In our group, we have been working on LSO background radiation for attenuation correction (AC) and our results are quite promising [1]. Until this moment, we have applied our approach to the Siemens 3T MR-BrainPET scanner available at our research center, which does not have Time-Of-Flight (TOF) capabilities. Therefore, the transmission and emission measurement cannot be performed simultaneously, but rather sequentially. This is incompatible with clinical practice and can only be done in research facilities. In this STSM, our goal is to apply the developed approach to the GE Signa scanner [2], which has TOF capabilities. For this purpose, we will perform measurements with the LSO background for two different phantoms (cylinder phantom and head phantom) without any activity, but also with activity to evaluate the AC performance. We will also acquire MR images of these phantoms. Furthermore, we will have to convert the acquired data to a format readable by our program, perform the necessary corrections and reconstruct the data. We will perform different pre-processing of the data: random correction, sinogram compression, bin calculations and reconstruction to evaluate the best processing pipeline. We will also evaluate the acquisition time necessary for obtaining a reasonable attenuation correction map.


 Università Politecnica delle Marche, Ancona

 European Organisation for Nuclear Research (CERN)

Duration: 2 months (24/01/2016 to 26/03/2016)

Influence of quality and stress conditions to luminescence performances of the scintillating crystals

Light production, transport, transmission and absorption in scintillating crystals are related to optical properties like the refractive indices. Refractive indices variations and distribution can be induced by defects, stress condition and orientation of the optic indicatrix. Some setups have been arranged at CERN in order to observe crystal condition and to induce stress distribution during luminescence properties measurements. Since the results from the previous STSM at CERN are encouraging, the activity aims to test more deeply the influence of quality and stress conditions to luminescence performances of the scintillating crystals by means of the arranged measurement benches.


 PETsys Electronics, SA, Lisboa Science and Technology Park

 Insitute of Nuclear Medicine, UCL Hospital, London

Duration: 6 weeks (20/2/2016 to 01/04/2016)

Study image reconstruction techniques for a dedicated breast scanner

The purpose of this project is to learn the new techniques in tomographic image reconstruction including the image normalization and plan and initiate the development of a fast TOF PET image reconstruction software based on STIR for a new PET prototype and later for a PET dedicated to breast. The challenge is to take advantage of the excellent time resolution made possible with SiPMs, and to demonstrate the corresponding improved image resolution.


 LIP, Lisbon

 University of Torino, Department of Physics

Duration: 3 weeks (1/2/2016 to 21/2/2016)

Development of a prototype amplifier and discriminator chip in CMS 110 nm technology for application in the CT-PPS timing detectors of the CMS experiment at LHC.

In the framework of the CT-PPS project the LIP group is pursuing a new version of the TOFPET chip suitable for the PPS timing detectors. A necessary step in this project is the design and test of the front-end part of the chip, which includes the amplifiers and discriminators, adapted to the Ultra Fast Silicon Sensors. The objective of the present STSM proposal is precisely the development of a new version of the front-end suitable for the UFSD. The design has to take into account the different characteristics of the silicon signal, in particular the fact that the typical signal charge is about 1 fC (100 times smaller than the 1 p.e. signal provided by SiPMs) and the very fast rising time of the signal. A new preamplifier stage adapted to the TOFPET2 input could be a possible solution, but other solutions are also being exploited. The development of circuits with the capability to provide time measurements with excellent resolution is one of the main motivations of the WG4 in the FAST network.


 Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University, Moscow

 European Organisation for Nuclear Research (CERN)

Duration: 1 week (23/1/2015 to 30/1/2015)

Intraband luminescence (IBL) properties

Theoretical estimations of the efficiency of intarband luminescence in different crystals. Dependence of intraband luminescence on electron band structure. Treating and discussion of experimental results of excitation of intraband luminescence. Discussion of other possible approaches for achievement of main goals of WG2.


 Università Politecnica delle Marche, Ancona

 European Organisation for Nuclear Research (CERN)

Duration: 5 days (15/2/2016 to 19/2/2016 )

Study the influence of the optical orientation and samples stress on the timing performances

The scintillating crystals are the fundamental components of high energy physics calorimeters and PET. Light production, transport, transmission and absorption are related to the different crystal species by means of the refractive indices. The optic indicatrix summarize the optic crystal behavior determining the the refractive indices by the Dielectric Impermeability tensor. Refractive indices variations and distribution can be induced by defects, stress condition and orientation. Luminescence properties measurements of crystals submitted to induced stress distribution and as a function of orientation are mandatory to test the light efficiency and decay time.


 Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University,Moscow

 Institut Lumière Matière, Villeurbanne

Duration: 14 days (28/2/2016 to 12/3/2016)

Experimental studies of the decay kinetics of Ce3+ emission in the mixed crystals of complex oxides.

Experimental studies of the decay kinetics of Ce3+ emission in the mixed crystals of complex oxides. Evaluation of Ce3+ emission rise time modification throughout the set of mixed crystals. Treating and discussion of the obtained experimental results. Discussion of other possible approaches for achievement of main goals of WG2.


 CPPM, Aix-Marseille Université, Marseille

 European Organisation for Nuclear Research (CERN)

Duration: 12 days (11/4/2016 to 22/4/2016)

Model of a spectrometric chain using a Silicon photo-multiplier (SiPM) to be integrated in the C++ digitizer module of the Monte Carlo simulation platform GATE

My objective is to develop a comprehensive model of a spectrometric chain using a Silicon photo-multiplier (SiPM) to be integrated in the C++ digitizer module of the Monte Carlo simulation platform GATE. Once validated, this development will be released within the GATE public version. The team at CERN has a long expertise in SiPM operation and characterization. Thus, the objective of this second short-term scientific mission (STSM) of two weeks will be to assess against experimental measurements performed at CERN the simulation results from the C++ modules that would have been developed in Marseille following the first STSM spent at CERN.


 Skobeltsyn Institute of Nuclear Physics of Lomonosov Moscow State University, Moscow

 Institut Lumière Matière, Villeurbanne

Duration: 7 days (6/3/2016 to 12/3/2016)

Experimental studies of the decay kinetics of Ce3+ emission in the mixed crystals of complex oxides.

Experimental studies of the decay kinetics of Ce3+ emission in the mixed crystals of complex oxides. Evaluation of Ce3+ emission rise time modification throughout the set of mixed crystals. Treating and discussion of the obtained experimental results. Skills acquisition in carrying out of the experiments to measure the fast decay kinetics using the X-ray source with ps time resolution.


 Institute of Neuroscience and Medicine (INM-4), Jülich

 Fondazione Bruno Kessler - FBK, Trento

Duration: 5 days (01/08/2016 to 05/08/2016)

The main goal of this STSM is to characterize Linearly-Graded Silicon Photomultiplier coupled to monolithic crystals. A first STSM focused on intrinsic resolution. The next step is to characterize the timing resolution.

An 8-by-8 mm² LG-SiPM prototype has been already developed by the FBK. Monolithic crystals can be provided by Forschungszentrum Jülich. With the existing hardware, the LG-SiPM 8-by-8 mm² monolithic based detectors can be characterized. The measurements should take place at FBK. The measurement will be prepared in cooperation between FBK and Forschungszentrum Jülich in advance. The planned measurement time in total is planned to be 5 days. The first days are for preparing the measurement setup. During the last days, the measurements will take place. An option is to let advanced measurements run after leaving the FBK, depending on the availability of the measurement setup. The results of these measurements should be published in paper providing a characterization of the timing resolution of the new 8-by-8 mm² LG-SiPM prototype coupled to monolithic crystal.


 Research Institute for Physical Chemical Problems of the Belarusian State University, Minsk

 Semiconductor Physics Department, Vilnius University

Duration: 8 days (30/05/2016 to 06/06/2016)

Study of luminescent and kinetics properties of garnets doped Ce(III)-ions with partial introduction of bivalent and tetravalent elements in lattice

The main idea of visit -- experiments on free carrier absorption in PWO and cerium-doped garnet. Luminescent and kinetics properties of garnets doped Ce(III)-ions with partial introduction of bivalent and tetravalent elements in lattice will be studied. The results can be interesting for understanding future modification of garnets with purpose to improve their scintillations properties. Furthermore, this visit will also serve for detailed discussions of results and determination of possibility to their presentation as a paper manuscript.

  • Determining the most appropriate bi- and thetravalent elements for implantation into the garnet structure;
  • Develop a method of synthesis of garnet powder with bi- and thetravalent elements;
  • Investigation the effect of the bi- and thetravalent elements on the structural properties of the granates;
  • Investigation the luminescent and kinetics properties of the obtained garnets;