Evaluation of the PETsys TOFPET2 ASIC in multi-channel coincidence experiments

EJNMMI Physics

Table 3 Coincidence resolution time (FWTM) and Gaussian excess factors gaussexc

	KETEK		SensL		Hamamatsu
	PA3325-WB-0808		Array-J-30020-64P-PCB		S14161-3050-HS-08
	CRT (FWTM)	gaussexc	CRT (FWTM)	gaussexc	CRT (FWTM)	gaussexc
Threshold vth_t1
10	524.6 ps	5.07%	528.9 ps	9.38%	424.1 ps	3.80%
20	514.2 ps	3.89%	514.6 ps	6.34%	420.1 ps	4.13%
30	511.4 ps	4.40%	517.2 ps	7.56%	416.7 ps	3.36%
40	501.6 ps	3.40%	504.3 ps	5.22%	417.0 ps	4.02%
50	503.6 ps	4.39%	507.7 ps	6.12%	416.4 ps	3.82%
Segmentation layer
BaSO₄ (360 µm)	503.6 ps	4.39%	507.7 ps	6.12%	416.4 ps	3.82%
BaSO₄ (110 µm)	542.6 ps	5.23%	604.9 ps	5.29%	464.9 ps	4.97%
ESR (67 µm, glued)	715.1 ps	5.61%	896.7 ps	6.13%	609.6 ps	8.37%
Distance
18 mm	539.6 ps	6.71%	-	-	-	-
38 mm	503.6 ps	4.39%	507.7 ps	6.12%	416.4 ps	3.82%
58 mm	463.8 ps	3.68%	477.2 ps	3.32%	419.9 ps	2.64%
Clinical (19 mm height)
ESR (155 µm, air-coupled)	601.9 ps	4.04%	617.2 ps	4.11%	462.3 ps	2.43%

Parameter study for multi-channel configurations featuring SiPMs by different vendors. Table reports the CRT (FWTM) and Gaussian excess factors corresponding to the lowest CRTs achieved in coincidence measurements of two times 64 channels (see Table 2). If not indicated differently, data were acquired at vth_t1=50, vth_t2=20, vth_e=15, with 360 µm BaSO₄ for scintillator segmentation, a scintillator height of 12 mm, and at a distance of 38 mm. The overvoltage setting varies according to the parameter setting and SiPM type used. The error on the reported CRTs (FWTM) is less than 0.1 ps. For the clinical configuration (19-mm high scintillator), only two times 16 channels were read out