A. Erven

PhenoPET: A dedicated PET scanner for plant research based on digital SiPMs (DPCs)

In the framework of the German Plant Phenotyping Network (DPPN) we developed a novel PET scanner for imaging plants and crops. The observation of the carbon transport within the plant becomes possible by using 11CO2 as PET tracer. The use of the rather short living isotope C-11 asks for a scanner with high dynamic range. That means fast timing and high data rates are important features which let us choose the Philips Digital Photon Counter (DPC) as photo detector. Due to the fast photo detectors and the special crystal matrix arrangement the system will allow measurements with rather high activities. We could measure a coincidence resolution time of ~ 250 ps FWHM between two detector elements. This opens the opportunity to employ time-of-flight information for the first time on a PET scanner of this size. This paper presents very first results from a prototype single-ring system with a FOV of 18 cm diameter and 6.5 cm axial height.

Read-out electronics for digital silicon photomultiplier modules

This work has its focus on the development of fast read-out electronics for digital silicon photomultipliers (dSiPM -called Digital Photon Counter (DPC) by Philips).

PET scintillator arrangement on digital SiPMs

A typical high resolution PET detector consists of a matrix of scintillator elements which are connected to a light guide in order to spread the light onto the pixels of a photo detector. In this work we introduce a matrix that works without light guide but has defined internal light leaks in order to allow controlled light sharing between the individual scintillator elements. This is especially useful when used together with the Philips digital SiPM DPC 3200. We show that better position determination is achieved and in addition higher count rates should be possible compared to a classical light guide solution.

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

This work describes the development of the first demonstrator device for neutron detection based on a 6Li-glass as a scintillator and silicon photomultipliers (SiPM) as photodetector. For the first characterization, the scintillator was pixelated with a one to one correspondence between scintillator and SiPM pixels, and optical cross-talk between pixels was minimized. Measurements in a high luminosity neutron beam show the functionality of the device and allow for partial characterization. The position resolution is 4 × 4mm2 and the detection efficiency of neutrons is 91(6)% relative to the active area. The device is linear up to at least 600 kcps.

PhenoPET — results from the plant scanner

Within the German Plant Phenotyping Network (DPPN), we developed a novel PET scanner based on Philips Digital Photon Counters (DPCs, or dSiPMs = digital Silicon Photomultipliers). The scanner is dedicated for plant research and provides functional information on carbon transport within the plant. To this end the detector ring is oriented horizontally. It provides a Field-of-View of 18 cm dia. and 20 cm in height. The read-out electronics cluster hits from different photodetector pixels when they originate from the same scintillation event. These single events are written via USB 3.0 with up to 300 MB/s to the computer system. Crystal identification, energy discrimination and coincidence detection is realized in software. The spatial resolution in the center Field-of-View (CFOV) could be estimated to approx. 1.6 mm from measurements of a dedicated hot rod phantom. Preliminary sensitivity measurements result in a peak sensitivity of 4.04% (ΔE = 250-750 keV) in the CFOV and a Coincidence Resolving Time of 298 ps could be achieved.

The use of USB 3.0 for fast data transfer in a PET detector

The Research Centre Juelich is developing a PET detector for plant phenotyping together with Philips Digital Photon Counting, Aachen. The scientific goal is to study the carbon transport in plants. To detect 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 the coincidences. It is assumed that the necessary data rate from the FPGA to the acquisition computer is about 300 MByte/s. As data link a 10-gigabit Ethernet link would be preferred, but the evaluation board contains a USB 3.0 interface already, therefore we chose to use this one in order to reduce the development costs.

ADC-Based Real-Time Signal Processing for the PANDA Straw Tube Tracker

The PANDA (AntiProton Annihilations at Darmstadt) experiment is being built at the new Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. PANDA will measure antiproton-proton annihilation reactions in the charm quark mass range to investigate the nature of the strong interaction. This particle physics experiment will run at very high reaction rates of 10-20 MHz. Our work is related to an ADC (analog-to-digital converter) based data acquisition system for the PANDA Straw Tube Tracker (STT). The STT will be able to deliver data rates up to 20 GByte/s through over 4600 signal channels and could require major efforts for the hardware implementation as well as high offline processing power. Test beam studies were carried out in order to specify a proper system architecture with feasible hardware and to reduce output data stream to a level suitable for offline processing. We analyze the straw tube response to both the proton beam and 55Fe irradiation. Furthermore, we present real-time processing using the neighboring straw information and introduce the technique to reconstruct the tracks.

Investigation of an ADC based signal processing and design of an ATCA data acquisition system unit for the Straw Tube Tracker at PANDA

The work concerns with ADC based data acquisition system for PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker (STT). Test-beam studies in terms of parameters and system architecture definition were carried out. We present on-FPGA real time processing dependent on neighboring straw data and introduce track reconstruction technique.

Sophisticated online analysis in ADC boards

For the readout of the calorimeter of the WASA-at-COSY experiment a QDC board using flash 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.