Speaker
Description
A prevailing trend in PET development is the use
of smaller SiPMs to achieve higher spatial resolution. However,
the resulting increase in SiPM quantity places a heavier burden
on the processing hardware. To address this without requiring
upgrades to the underlying readout electronics, multiple SiPM
signals can be multiplexed into a single channel. This approach is
utilized in the Hyperion PET detector platform, which integrates
both SiPMs and digitizing ASICs. The platform consists of sensor
tiles connected to the module mainboards via flexible cables.
By leveraging versatile analog SiPM and ASIC combinations,
these tiles are adaptable for various PET/MRI projects. The
initial implementation will feature a 48 x 48 mm2 form factor
utilizing 4 mm SiPMs. Through signal compression, the 144
SiPMs will be read by a single 64-channel TOFPET ASIC,
significantly optimizing spatial footprint, power consumption,
and overall costs. A range of channel compression schemes
with a factor of at least 2.25 are currently under investigation.
Five different compression schemes that do not use additional
electronic components are proposed. For comparison the row-
column-sum approach with additional resistors was also included
in the investigations. For local compression schemes SiPMs in
close proximity are connected in parallel while for more global
compression schemes distances between connected SiPMs are
maximized. The simple patterns allow straightforward algorithms
for crystal identification, whereas other more optimized patterns
employ more advanced processing algorithms, like neural net-
works, for this task. Measurements with 4 mm pixels show that
the mean absolute error only slightly increases from ∼1.25 mm
to ∼1.32 mm when using one of the local compression schemes in
comparison to using uncompressed data. Furthermore measure-
ments with 2 mm Slabs show using smaller 4 mm SiPMs with
compression schemes was still advantageous over using bigger
6 mm SiPMs for almost all investigated compression schemes. The
energy resolution is also effected by the choice of compression
scheme. Preliminary results show that using local compression
schemes as tetris and fishbone can even improve the energy
resolution over non compressed data. Test PCBs were designed
for SiPMs and for the compression schemes as interposing
PCBs. At the same time, a sensor tile is being designed with
a TOFPET2 ASIC and an FPGA on the electronics side and just
two connectors for the SIPMs on the other side. Consequently,
the digitizing ASIC, compression schemes, and SiPMs can be
combined freely.
| Track | PSMR |
|---|---|
| Presentation type | Oral |