Read-out electronics for digital silicon photomultiplier modules

A new kind of a PET-Scanner (PET = positron emission tomography) for plant research is developed asa joint project of the Forschungszentrum Jülich and Philips Digital Photon Counting (PDPC). Thisscanner will utilize digital silicon photomultiplier (dSiPM) for plant phenotyping for the very first time.The goal of this work is to get a further knowledge of the operation of digital silicon photomultiplier.On this account a test-facility for this new photo detectors has been installed at the central instituteof engineering, electronics and analytics (ZEA-2 electronic systems) to determine the usage of thissensors, having regard to use them as scintillation detectors in a PET-Scanner later on.This work has its focus on the development of a fast read-out electronic for the used photo sensorsDPC3200-22-44. As there will be high data rates a fast USB 3.0 interface has been used. All thenecessary processing and data handling has been implemented in a state of the art FPGA

phenoPET: A dedicated PET Scanner for Plant Research based on digital SiPMs

In the frame of the German Plant Phenotyping Project (DPPN) we developed a novel PET scanner. In contrary to a clinical or preclinical PET scanner the detector rings of the Plant System are oriented in a horizontal plane. The final system will be equipped with three rings covering a Field of View (FOV) of 18 cm diameter and 20 cm axial height. One detector ring is formed by 12 modules. Each module contains four 8×8 pixel digital SiPM devices DPC-3200-22-44 (Philips Digital Photon Counting) connected to a PCB and four scintillator matrices with 16×16 individual LYSO scintillators. Crystal size is 1.85×1.85×10 mm3. The matrices are composed with both reflective and transparent contact faces between the crystals in order to optimize crystal identification. A cooling system keeps the detectors below 5°C and limits the dark count rate. Data are already preprocessed by the Cyclone FPGA (Altera) in the module and transmitted from there at 50MiB/s to the base board. The base board collects the data from all modules and allows coincidence detection performed on a Kintex-7 FPGA (Xilinx). Finally the data link to the computer system for image reconstruction is realized via an USB 3.0 connection. Due to the fast photodetectors the system is dedicated to work with rather high activities. Preliminary measurements showed a coincidence peak of 250 ps FWHM between two detector elements and an energy resolution ΔE/E = 12%. This paper will present first results from a one ring system with a FOV of 18 cm diameter and 6.5 cm axial height

„Verfahren zur Bestimmung einer Ankunftszeit eines eine physikalische Meßgröße repräsentierenden, digitalisierten Signalpulses, Auswerteeinheit, Vorrichtung, Auswertsystem und Strahlendetektionssystem"

Die Erfindung betrifft ein Verfahren zur Bestimmung einer Ankunftszeit (t) eines eine physikalische Messgröße repräsentierenden, digitalisierten Signalpulses (P), wobei- bestimmt wird, welche Form die steigende Flanke (F) des Signalpulses (P) aufweist, wobei die Form ausgewählt wird aus der Gruppe umfassend- einen zumindest im Wesentlichen linearen Anstieg,- einen nichtlinearen Anstieg ohne Wendepunkt (pi) und- einen S-ähnlichen nichtlinearen Anstieg mit wenigstens einem Wendepunkt (pi),- in allen drei Fällen eine Differenz zwischen dem Zeitpunkt (t) des ersten Abtastpunktes (s) des Signalpulses (P) und der Ankunftszeit (t) des Signalpulses (P) berechnet wird über die Gleichung- unter Berücksichtigung des erhaltenen Wertes für Δt die Ankunftszeit (t) des Signalpulses (P) berechnet wird.Darüber hinaus betrifft die Erfindung eine Auswerteeinheit und eine Vorrichtung zur Bestimmung einer Ankunftszeit von eine physikalische Messgröße repräsentierenden Signalpulsen, ein Auswertesystem und ein Strahlendetektionssystem

Sophisticated Online Analysis in ADC Boards

For the readout of the calorimeter of the WASA at COSY experiment a QDC board using sampling ADCs and FPGAs to perform the pulse integration was developed. In the initial version only a simple pulse finding algorithm was implemented in order to avoid delay cables by storing the digitized signals in a pipeline of a few microseconds. Recently a new version with 16 ADCs at a sample rate of 240 MHz and 12 Bit resolution was developed for tests of cylindrical drift chambers (straw tubes) in the Straw Tube Tracker of the PANDA experiment. The goal was to measure the energy loss by charge readout in addition to drift time measurement. Due to the irregular cluster structure of the straw signals complex algorithms for pulse finding, pulse feature extraction and triggering were implemented. The algorithm can detect pile up and find pulse groups. Integration is possible over single pulses and over complete groups. Different methods for the calculation of starting time, including constant fraction, are implemented. Internal trigger generation depends on various criteria, e.g. slew rate, amplitude or sum of consecutive samples

The Use of USB 3.0 for Fast Data Transfer in a Plant PET Detector

The Research Centre Juelich is developing a PET detector for plant phenotyping together with Philips Digital PhotonCounting, Aachen. The scientific goal is to study the carbon transport in plants. The poster will give an overview overthe whole project, but will focus on the use of USB 3.0 to transfer data from the FPGA to the acquisition computer. Todetect the photon pairs we use a ring of digital photon counters recently developed by Philips.For the prototype we decided to use a Xilinx Kintex evaluation board for data concentration and processing of thecoincidences. It is assumed that the necessary data rate from the FPGA to the acquisition computer is about 300MByte/s. As data link a 10-gigabit Ethernet link would be preferred, but the evaluation board contains a USB 3.0interface already, therefore we chose to use this one in order to reduce the development costs. The poster will discussthe pros and cons of the use of USB for data acquisition and the results achieved so far

Development and characterization of a 4 × 4 mm² pixel neutron scintillation detector using digital SiPMs

This work describes the development of the first demonstrator device for neutrondetection based on a 6 Li-glass as a scintillator and silicon photomultipliers (SiPM) as photodetector.For the first characterization, the scintillator was pixelated with a one to one correspondence betweenscintillator and SiPM pixels, and optical cross-talk between pixels was minimized. Measurementsin a high luminosity neutron beam show the functionality of the device and allow for partialcharacterization. The position resolution is 4 ×4 mm² and the detection efficiency of neutrons is91(6) % relative to the active area. The device is linear up to at least 600 kcps

ADC based signal processing for the Straw Tube Tracker at PANDA

Test-beam studies in terms of parameters and system architecture definition were carried out. We present the technique allowing step by step integration of on-FPGA real time processing dependent on neighboring straw data from low level up to fully track reconstruction with self-triggering feature

SiPM-based Scintillator Detectors for Small Angle Neutron Scattering Experiments

Small Angle Neutron Scattering (SANS) technique uses cold or thermal neutrons for investigation of soft and condensed matter. Significant developments in microelectronics enabled scintillation-based pixelated neutron detectors that use Silicon Photomultipliers (SiPM) for detecting the visible light generated within a scintillator. We characterized three different SiPM technologies in terms of their radiation hardness. The results of this first study are presented together with the first preliminary characterization results obtained in a beam of cold neutrons of a demonstrator consisting of a 1 mm thick Ce doped 6Li-glass optically coupled to an 8 × 8 pixel Philips DPC module