@article{StreunBrandenburgBroekeletal.2004, author = {Streun, M. and Brandenburg, G. and Br{\"o}kel, M. and Fuss, L. and Larue, H. and Parl, C. and Zimmermann, E. and Ziemons, Karl and Halling, H.}, title = {The ClearPET data acquisition}, series = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5}, journal = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 5}, issn = {1082-3654}, pages = {3097 -- 3100}, year = {2004}, abstract = {Within the Crystal Clear Collaboration a modular system for a small animal PET scanner (ClearPET™) has been developed. The modularity allows the assembly of scanners of different sizes and characteristics in order to fit the specific needs of the individual member institutions. Now a first demonstrator is being completed in Julich. The system performs depth of interaction detection by using a phoswich arrangement combining LSO and LuYAP scintillators which are coupled to multi-channel photomultipliers (PMTs). A free-running ADC digitizes the signal from the PMT and the complete scintillation pulses are sampled by an FPGA and sent with 20 MB/S to a PC for preprocessing. The pulse provides information about the gamma energy and the scintillator material which identifies the interaction layer. Furthermore, the exact pulse starting time is obtained from the sampled data. This is important as no hardware coincidence detection is implemented. All single events are recorded and coincidences are identified by software. An advantage of that is that the coincidence window and the dimensions of the field of view can be adjusted easily. The ClearPET™ demonstrator is equipped with 10240 crystals on 80 PMTs. This paper presents an overview of the data acquisition system.}, language = {en} } @article{ChristHollendungLarueetal.2004, author = {Christ, D. and Hollendung, A. and Larue, H. and Parl, C. and Streun, M. and Weber, S. and Ziemons, Karl and Halling, H.}, title = {Homogenization of the MultiChannel PM gain by inserting light attenuating masks}, series = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 4}, journal = {2003 IEEE Nuclear Science Symposium Conference Record, Vol. 4}, issn = {1082-3654}, pages = {2382 -- 2385}, year = {2004}, abstract = {MultiChannel Photomultipliers (PM), like the R7600-00-M64 or R5900-00-M64 from Hamamatsu, are often chosen as photodetectors in high-resolution positron emission tomography (PET). A major problem of this PM is the nonuniform channel gain. In order to solve this problem, light attenuating masks were created. The aim of the masks is a homogenization of the output of all 64 channels using different hole sizes at the channel positions. The hole area, which is individually defined for the different channels, is inversely proportional to the channel gain. The measurements by inserting light attenuating masks improved a homogenization to a ratio of 1:1.2.}, language = {en} } @article{StreunChristHellendungetal.2005, author = {Streun, M. and Christ, D. and Hellendung, A. and Larue, H. and Ziemons, Karl and Halling, H.}, title = {Effects of crosstalk and gain nonuniformity using multichannel PMTs in the Clearpet® scanner}, series = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, volume = {537}, journal = {Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, number = {1-2}, isbn = {0168-9002}, pages = {402 -- 405}, year = {2005}, abstract = {The ClearPET® scanners developed by the Crystal Clear Collaboration use multichannel PMTs as photodetectors with scintillator pixels coupled individually to each channel. In order to localize an event each channel anode is connected to a comparator that triggers when the anode signal exceeds a common predefined threshold. Two major difficulties here are crosstalk of light and the gain nonuniformity of the PMT channels. Crosstalk can generate false triggering in channels adjacent to the actual event. On the one hand this can be suppressed by sufficiently increasing the threshold, but on the other hand a threshold too high can already prevent valid events on the lower gain channels from being detected. Finally, both effects restrict the dynamic range of pulse heights that can be processed. The requirements to the dynamic range are not low as the ClearPET® scanners detect the depth of interaction by phoswich pixels consisting of LSO and Lu0.7Y0.3AP, two scintillators with different light yields. We will present a model to estimate the achievable dynamic range and show solutions to increase it.}, language = {en} } @inproceedings{TersteggeWeberHerzogetal.1997, author = {Terstegge, Andreas and Weber, S. and Herzog, H. and M{\"u}ller-G{\"a}rtner, H. W. and Halling, H.}, title = {Design and implementation aspects of a 3D reconstruction algorithm for the J{\"u}lich TierPET system}, series = {1997 International Meeting on Fully ThreeDimensional Image Reconstruction in Radiology and Nuclear Medicine : 3D97}, booktitle = {1997 International Meeting on Fully ThreeDimensional Image Reconstruction in Radiology and Nuclear Medicine : 3D97}, pages = {170 -- 173}, year = {1997}, language = {en} } @inproceedings{WeberTersteggeEngelsetal.1996, author = {Weber, S. and Terstegge, Andreas and Engels, R. and Herzog, H. and Reinartz, R. and Reinhart, P. and Rongen, F. and M{\"u}ller-G{\"a}rtner, H. W. and Halling, H.}, title = {The KFA TierPET: performance characteristics and measurements}, series = {Conference record / 1996 IEEE Nuclear Science Symposium [and Medical Imaging], November 2 - 9, 1996, Anaheim, California ; vol. 2}, booktitle = {Conference record / 1996 IEEE Nuclear Science Symposium [and Medical Imaging], November 2 - 9, 1996, Anaheim, California ; vol. 2}, publisher = {IEEE}, address = {Piscataway, NJ}, organization = {Institute of Electrical and Electronics Engineers}, isbn = {0-7803-3534-1}, issn = {1082-3654}, pages = {1117 -- 1119}, year = {1996}, language = {en} } @inproceedings{WeberTersteggeHallingetal.1995, author = {Weber, S. and Terstegge, Andreas and Halling, H. and Herzog, H. and Reinartz, R. and Reinhart, P. and Rongen, F. and M{\"u}ller-G{\"a}rtner, H.-W.}, title = {The design of an animal PET: flexible geometry for achieving optimal spatial resolution or high sensitivity}, series = {Conference record / 1995 IEEE Nuclear Science Symposium and Medical Imaging, October 21 - 28, 1995, San Francisco ; vol. 2}, booktitle = {Conference record / 1995 IEEE Nuclear Science Symposium and Medical Imaging, October 21 - 28, 1995, San Francisco ; vol. 2}, publisher = {IEEE}, address = {Piscataway, NJ}, organization = {Institute of Electrical and Electronics Engineers}, isbn = {078033180X ; 0780331818 ; 0780331826}, pages = {1002 -- 1005}, year = {1995}, language = {en} }