TY  - JOUR
A1  - Christ, D.
A1  - Hollendung, A.
A1  - Larue, H.
A1  - Parl, C.
A1  - Streun, M.
A1  - Weber, S.
A1  - Ziemons, Karl
A1  - Halling, H.
T1  - Homogenization of the MultiChannel PM gain by inserting light attenuating masks
JF  - 2003 IEEE Nuclear Science Symposium Conference Record, Vol. 4
N2  - 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.
Y1  - 2004
SN  - 1082-3654
SP  - 2382
EP  - 2385
ER  - 
TY  - JOUR
A1  - Beer, S.
A1  - Streun, M.
A1  - Hombach, T.
A1  - Buehler, J.
A1  - Jahnke, S.
A1  - Khodaverdi, M.
A1  - Larue, H.
A1  - Minwuyelet, S.
A1  - Parl, C.
A1  - Roeb, G.
A1  - Schurr, U.
A1  - Ziemons, Karl
T1  - Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants
JF  - Physics in Medicine and Biology
N2  - Positron emitters such as 11C, 13N and 18F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is 11CO2 since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies. Detectors, front-end electronics and data acquisition architecture of the scanner are based on the ClearPET™ system. The detectors consist of LSO and LuYAP crystals in phoswich configuration which are coupled to position-sensitive photomultiplier tubes. Signals are continuously sampled by free running ADCs, and data are stored in a list mode format. The detectors are arranged in a horizontal plane to allow the plants to be measured in the natural upright position. Two groups of four detector modules stand face-to-face and rotate around the field-of-view. This special system geometry requires dedicated image reconstruction and normalization procedures. We present the initial performance of the detector system and first phantom and plant measurements.
Y1  - 2010
U6  - http://dx.doi.org/10.1088/0031-9155/55/3/006
SN  - 1361-6560
VL  - 55
IS  - 3
SP  - 635
EP  - 646
PB  - IOP
CY  - Bristol
ER  -