TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Coincidence detection by digital processing of free-running sampled pulses
JF  - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
N2  - 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.
Y1  - 2002
SN  - 0168-9002
VL  - 487
IS  - 3
SP  - 530
EP  - 534
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Brandenburg, G.
A1  - Larue, H.
A1  - Zimmermann, E.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - A PET system based on data processing of free-running sampled pulses
JF  - 2001 IEEE Nuclear Science Symposium Conference Record, Vol. 2
N2  - 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.
Y1  - 2002
SN  - 1082-3654
SP  - 693
EP  - 694
ER  - 
TY  - JOUR
A1  - Streun, M.
A1  - Christ, D.
A1  - Hellendung, A.
A1  - Larue, H.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Effects of crosstalk and gain nonuniformity using multichannel PMTs in the Clearpet® scanner
JF  - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
N2  - 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.
Y1  - 2005
SN  - 0168-9002
N1  - Proceedings of the 7th International Conference on Inorganic Scintillators and their Use in Scientific and Industrial Applications
VL  - 537
IS  - 1-2
SP  - 402
EP  - 405
ER  - 
TY  - CHAP
A1  - Terstegge, Andreas
A1  - Weber, S.
A1  - Herzog, H.
A1  - Müller-Gärtner, H. W.
A1  - Halling, H.
T1  - Design and implementation aspects of a 3D reconstruction algorithm for the Jülich TierPET system
T2  - 1997 International Meeting on Fully ThreeDimensional Image Reconstruction in Radiology and Nuclear Medicine : 3D97
Y1  - 1997
SP  - 170
EP  - 173
ER  - 
TY  - CHAP
A1  - Weber, S.
A1  - Terstegge, Andreas
A1  - Engels, R.
A1  - Herzog, H.
A1  - Reinartz, R.
A1  - Reinhart, P.
A1  - Rongen, F.
A1  - Müller-Gärtner, H. W.
A1  - Halling, H.
T1  - The KFA TierPET: performance characteristics and measurements
T2  - Conference record / 1996 IEEE Nuclear Science Symposium [and Medical Imaging], November 2 - 9, 1996, Anaheim, California ; vol. 2
Y1  - 1996
SN  - 0-7803-3534-1
SN  - 1082-3654
SP  - 1117
EP  - 1119
PB  - IEEE
CY  - Piscataway, NJ
ER  - 
TY  - CHAP
A1  - Weber, S.
A1  - Terstegge, Andreas
A1  - Halling, H.
A1  - Herzog, H.
A1  - Reinartz, R.
A1  - Reinhart, P.
A1  - Rongen, F.
A1  - Müller-Gärtner, H.-W.
T1  - The design of an animal PET: flexible geometry for achieving optimal spatial resolution or high sensitivity
T2  - Conference record / 1995 IEEE Nuclear Science Symposium and Medical Imaging, October 21 - 28, 1995, San Francisco ; vol. 2
Y1  - 1995
SN  - 078033180X ; 0780331818 ; 0780331826
SP  - 1002
EP  - 1005
PB  - IEEE
CY  - Piscataway, NJ
ER  -