@article{StreunBrandenburgLarueetal.2002,
  author    = {Streun, M. and Brandenburg, G. and Larue, H. and Zimmermann, E. and Ziemons, Karl and Halling, H.},
  title     = {Coincidence detection by digital processing of free-running sampled pulses},
  series = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  volume    = {487},
  journal   = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  number    = {3},
  isbn      = {0168-9002},
  pages     = {530 -- 534},
  year      = {2002},
  abstract  = {Coincident events in two scintillator crystals coupled to photomultipliers (PMT) are detected by processing just the digital data of the recorded pulses. For this purpose the signals from both PMTs are continuously sampled by free-running ADCs at a sampling rate of 40 MHz. For each sampled pulse the starting time is determined by processing the pulse data. Even a fairly simple interpolating algorithm results in a FWHM of about 2 ns.},
  language  = {en}
}
@article{StreunBrandenburgLarueetal.2002,
  author    = {Streun, M. and Brandenburg, G. and Larue, H. and Zimmermann, E. and Ziemons, Karl and Halling, H.},
  title     = {A PET system with free running ADCs},
  series = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  volume    = {486},
  journal   = {Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment},
  number    = {1-2},
  issn      = {0168-9002},
  pages     = {18 -- 21},
  year      = {2002},
  abstract  = {A small PET system has been built up with two multichannel photomultipliers, which are attached to a matrix of 64 single LSO crystals each. The signal from each multiplier is being sampled continuously by a 12 bit ADC at a sampling frequency of 40 MHz. In case of a scintillation pulse a subsequent FPGA sends the corresponding set of samples together with the channel information and a time mark to the host computer. The data transfer is performed with a rate of 20 MB/s. On the host all necessary information is extracted from the data. The pulse energy is determined, coincident events are detected and multiple hits within one matrix can be identified. In order to achieve a narrow time window the pulse starting time is refined further than the resolution of the time mark (=25 ns) would allow. This is possible by interpolating between the pulse samples. First data obtained from this system will be presented. The system is part of developments for a much larger system and has been created to study the feasibility and performance of the technique and the hardware architecture.},
  language  = {en}
}
@article{StreunBrandenburgLarueetal.2002,
  author    = {Streun, M. and Brandenburg, G. and Larue, H. and Zimmermann, E. and Ziemons, Karl and Halling, H.},
  title     = {A PET system based on data processing of free-running sampled pulses},
  series = {2001 IEEE Nuclear Science Symposium Conference Record, Vol. 2},
  journal   = {2001 IEEE Nuclear Science Symposium Conference Record, Vol. 2},
  issn      = {1082-3654},
  pages     = {693 -- 694},
  year      = {2002},
  abstract  = {Within the developments for the Crystal Clear small animal PET project (CLEARPET) a dual head PET system has been established. The basic principle is the early digitization of the detector pulses by free running ADCs. The determination of the γ-energy and also the coincidence detection is performed by data processing of the sampled pulses on the host computer. Therefore a time mark is attached to each pulse identifying the current cycle of the 40 MHz sampling clock. In order to refine the time resolution the pulse starting time is interpolated from the samples of the pulse rise. The detector heads consist of multichannel PMTs with a single LSO scintillator crystal coupled to each channel. For each PMT only one ADC is required. The position of an event is obtained separately from trigger signals generated for each single channel. An FPGA is utilized for pulse buffering, generation of the time mark and for the data transfer to the host via a fast I/O-interface.},
  language  = {en}
}