June 7-12, 2015 | Hotel Shattuck Plaza, Berkeley
2086 Allston Way,  Berkeley, California, USA

R E G I S T R A T I O N 


Sunday -Tutorial Speakers

Monday - Plenary Speakers

Friday -  Plenary Speakers

T1-1: S. Kerisit

T1-2: P. Feng

T1-3: S. Gundaker

O1-2: P. Lecoq

O2-1: P. Di Stefano

O2-2: P. Schotanus

O3-1: G. Pratx




Sunday Tutorial Speakers


S. Kerisit

Pacific Northwest National Laboratory, Richland, WA, U.S.A

Tutorial 1: Calculational Approaches to Scintillation Properties

  Computational approaches spanning a range of length and time scales are increasingly being developed and applied to simulate scintillator materials. Today, researchers are turning to computational methods for a variety of reasons such as to interpret and rationalize experimental data, further the developments of comprehensive physics models, and generate quantitative predictions of scintillator performance. In this tutorial, I will provide a review of the computational approaches available to today’s researchers for simulating inorganic scintillator materials (electronic structure calculations, Monte Carlo simulations, etc.). The first part of the tutorial will concentrate on presenting the major fundamental concepts underlying these approaches, their areas of applicability, and examples of scintillation properties that can be calculated and physical insights that have been gained from each. In the second part of this tutorial, I will focus in greater depth on one or two specific examples, using the gamma-ray response of common alkali halide scintillators CsI and NaI as an example of how to construct a computational model that can account for experimental observations on the kinetics and efficiency of scintillation, as a function of parameters such as incident energy, temperature, and activator concentration. 

P. Feng

Sandia National Laboratories, Livermore, CA, U.S.A.

Tutorial 2: Molecular Origins of Scintillation in Plastic Scintillators

Plastic scintillators are indispensable materials for radiation detection owing to their low cost, ease of manufacturability, and durable mechanical properties. Over the past few years, there has been a resurgence of interest in plastic scintillators due to exciting discoveries related to neutron discrimination and gamma-ray spectroscopy, which represent capabilities previously thought not possible in plastics. In this tutorial I will discuss the origins of scintillation in organic-based materials, as relevant to the design and manufacture of these emerging classes of plastic scintillators. Particular attention will be paid to the different energy-transfer mechanisms that control the observed light yields, energy resolution, and timing response. A brief review of contemporary plastic scintillator research will also be provided.



S. Gundacker

CERN, Geneva, Switzerland

Tutorial 3: Practical Guide to Using SiPMs

     Geiger-mode avalanche photodiodes (G-APDs) or often called silicon photomultipliers (SiPMs), because of their ability to detect single photons like photomultiplier tubes (PMTs), become increasingly interesting in medical and high energy physics applications. They combine compactness and insensitivity to magnetic fields as well as very good single photon resolution and excellent timing properties. Generally SiPMs impose a different electronic readout strategy, when compared to PMTs or microchannel plates (MCPs), because of there relatively high terminal capacitance and long recovery times. In this tutorial we will discuss the main parameters characterizing these devices, e.g the SiPM's equivalent circuit, breakdown voltage, crosstalk, afterpulsing, recovery time, photon detection efficiency and single photon time resolution. Examples of practical electronic readout will be given, in order to achieve best single photon resolution, energy resolution and timing resolution. We as well will discuss coincidence time resolution measurements in a TOF-PET like system and investigate the electronics in order to achieve highest timing performances.




Monday- Plenary Speakers


P. Lecoq

CERN, Geneva, Switzerland

Fast Timing with Scintillators : Towards 10 ps Time Resolution ?

   The future generation of radiation detectors is more and more demanding on timing performance for a wide range of applications, such as time of flight (TOF) techniques for PET cameras and particle identification in nuclear physics and high energy physics detectors, precise event time tagging in high luminosity accelerators and a number of photonic applications based on single photon detection.The time resolution of a scintillator-based detector is directly driven by the density of photoelectrons generated in the photodetector at the detection threshold. At the scintillator level it is related to the intrinsic light yield, the pulse shape (rise time and decay time) and the light transport from the gamma-ray conversion point to the photodetector. When aiming at 10ps time resolution fluctuations in the thermalization and relaxation time of hot electrons and holes generated by the interaction of ionization radiation with the crystal become important. These processes last for up to a few tens of ps and are followed by a complex trapping-detrapping process, Poole-Frenkel effect, Auger ionization of traps and electron-hole recombination, which can last for a few ns with very large fluctuations.

   This talk will review the different processes at work and evaluate if some of the transient phenomena taking place during the fast thermalization phase can be exploited to extract a time tag with a precision in the few ps range.

   Some considerations will also be given on the possibility to exploit quantum confinement for the production of ultrafast spontaneous or stimulated emission in semi-conductors. A particularly promising route toward ultrafast emission comes in the form of 2D CdSe nanosheets. This system is characterized by confinement in only one dimension and free electron and hole motion in the plane, which contributes to a giant oscillator strength transition and ultrafast radiative emission rates. Further, CdSe nanosheets have ultralow thresholds for stimulated emission, with a lifetime of less than 1 picosecond. The light transport in the crystal is also an important source of time jitter. In particular light bouncing within the scintillator must be reduced as much as possible as it spreads the arrival time of photons on the photodetector and strongly reduces the light output by increasing the effect of light absorption within the crystal. It concerns typically about 70% of the photons generated in currently used scintillators. A possible solution to overcome these problems is to improve the light extraction efficiency at the first hit of the photons on the crystal/photodetector coupling face by means of photonic crystals (PhCs) specifically designed to couple light propagation modes inside and outside the crystal at the limit of the total reflection angle.   


P. Di Stefano

Queen's University,
Kingston, ON, Canada

 Dark Matter Search

    The mystery of dark matter is that most of the matter in the universe appears only through its gravitational interactions.  Particle physics may provide an explanation in the form of new particles beyond the Standard Model.  Detecting them directly is a challenge because of the small energies and the minuscule rates involved.  Detector requirements include low threshold, draconian radiopurity and the ability to distinguish between different types of interacting particles.  Scintillators have played an important role in these searches, most recently in the guise of cryogenic detectors in which the measurement of light is coupled to one of phonons, enabling particle identification.  There has also been a renewal of interest in alkali halide scintillators to verify a longstanding, but controversial, claim of dark matter detection.  Lastly, brittle fracture as a possible background in scintillators for rare-event searches will be discussed. 




P. Schotanus

Scionix, Holland

 Development and application of novel scintillators on an industrial scale

    Last years a growing number of new scintillation materials have been discovered/developed for applications in science and industry (LaBr3:Ce,  CLYC:Ce, SrI2(Eu), CeBr3, G(Y)AGG:Ce etc). At the same time we see a strongly renewed interest in novel organic scintillators suitable for neutron/gamma discrimination and a revival some old organic materials like Stilbene.
In this presentation we describe the difficulties and hurdles before new materials are actually used at a larger scale in radiation detection instrumens or “real size” scientific experiments.
An important aspect in the industrialisation of novel scintillation crystals is the performance specification. It will be shown that there are large difference between data in scientific publications and what is realistic in an real instrument.
Some recent examples of the application of novel scintillators in industry are presented.



Friday - Plenary Speakers


G. Pratx

Medical Physics and Radiation Oncology, Stanford University School of Medicine, Palo Alto, U.S.A.

One is More: New Radionuclide Approaches for Studying Single Cells

The conventional techniques used in biology require large numbers of cells and can only measure the average characteristics of a given cell population. There is growing evidence that the average of a cell population may not faithfully recapitulate the properties of its individual members. New techniques that can analyze single cells are thus being developed and applied to answer biologically motivated questions. In this context, radionuclide methods offer much promise due to their unmatched sensitivity and their compatibility with a wide range of small-molecule probes. In this talk, we will present radioluminescence microscopy, a novel microscopy technique that allows radionuclide probes to be imaged with 20 μm resolution inside a conventional microscopy environment. To localize individual beta emissions emanating from single live cells, the method uses a scintillator, whose design must be carefully optimized to yield high image quality. This imaging technique has be used to probe the heterogeneous dynamics of living cells and better understand the unique properties of rare cell types such as cancer stem cells or circulating tumor cells. We will conclude this presentation with a look at how single cells may also be tracked in vivo using radionuclide labeling and PET.






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