Performance of Scintillation Pixel Detectors with MPPC Read-out and Digital Signal Processing

Makek, M.; Bosnar, D.; Gačić, Valentina; Pavelić, Luka; Šenjug, Pavla; Žugec, P.

doi:10.5506/aphyspolb.48.1721

Cited by 3 publications

(7 citation statements)

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“…An energy correlation between the adjacent crystal pixels had been observed, as reported in [11]. When a significantly large signal is observed in a pixel, small signals are observed in adjacent pixels, with amplitudes proportional to the main signal amplitude, as demonstrated in Figure 3.…”

Section: Light Sharing Correctionsupporting

confidence: 58%

“…Signals from each channel are first amplified, then digitized by fast pulse digitizers (CAEN V1743) at 1.6 GS/s and stored for offline analysis. A detailed description of the experimental setup and the detector performance is given in [11]. In the setup presented in this work, we additionally applied silicon grease as the optical coupling medium between the scintillators and the SiPMs (see Subsection 2.2 for details).…”

Section: Methodsmentioning

confidence: 99%

“…The raw energy spectrum is obtained as the spectrum of signal integrals for each pixel. It is first corrected for non-linearity, which is present due to the finite number of micro cells per SiPM, as described in [11]. Then, it is calibrated by fitting a Gaussian to the annihilation peak and setting the corresponding value to 511 keV.…”

Section: Energy Calibrationmentioning

confidence: 99%

“…Most notably, the peak maximum is shifted upwards ∼30 keV for the events where the fired pixels are adjacent neighbors, while much lower shifts (<10 keV) are observed when the fired pixels are more distant neighbors. The observed shifts had been attributed to light sharing between the pixels [11]. A procedure to correct this effect and reconstruct the real energy depositions is presented in Section 2.4.2.…”

Section: Energy Resolutionmentioning

confidence: 99%

“…We assembled single-layer Compton detectors, and a system of two such modules was set up, as described in [11]. Each module consists of a 4 × 4 scintillator pixel array, read out on the back side by a matching array of Silicon Photomultipliers (SiPM) in a one-to-one coupling scheme.…”

Section: Introductionmentioning

confidence: 99%

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Scintillator Pixel Detectors for Measurement of Compton Scattering

2019

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The Compton scattering of gamma rays is commonly detected using two detector layers, the first for detection of the recoil electron and the second for the scattered gamma. We have assembled detector modules consisting of scintillation pixels, which are able to detect and reconstruct the Compton scattering of gammas with only one readout layer. This substantially reduces the number of electronic channels and opens the possibility to construct cost-efficient Compton scattering detectors for various applications such as medical imaging, environment monitoring, or fundamental research. A module consists of a 4 × 4 matrix of lutetium fine silicate scintillators and is read out by a matching silicon photomultiplier array. Two modules have been tested with a 22 Na source in coincidence mode, and the performance in the detection of 511 keV gamma Compton scattering has been evaluated. The results show that Compton events can be clearly distinguished with a mean energy resolution of 12.2% ± 0.7% in a module and a coincidence time resolution of 0 . 56 ± 0 . 02 ns between the two modules.

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Section: Light Sharing Correctionsupporting

confidence: 58%

Section: Methodsmentioning

confidence: 99%

Section: Energy Calibrationmentioning

confidence: 99%

Section: Energy Resolutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Scintillator Pixel Detectors for Measurement of Compton Scattering

2019

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Single-layer Compton detectors for measurement of polarization correlations of annihilation quanta

Makek

Bosnar

Pavelić

et al. 2020

Nuclear Instruments and Methods in Physics Research Section A:

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Measurement of gamma-ray polarization can provide valuable insight in different areas of physics research. One possible application is in Positron Emission Tomography, where the annihilation quanta with orthogonal polarizations are emitted. Since polarization can be measured via Compton scattering, the initial orthogonality of polarizations can be translated to correlation of azimuthal scattering angles, and this correlation may be exploited as an additional handle to identify the true coincidence events. In order to examine the concept of utilizing the polarization correlations in PET, we have used a system of two compact, position and energy-sensitive Compton scattering detectors in coincidence mode. Each consists of a single matrix of scintillation pixels, read-out by a matching array of Silicon photomultipliers on the back side. The Compton events in each module are clearly identified and the scattering angles are reconstructed from the energy deposition and event topology. We have extracted the polarimetric modulation factors from the distributions of the difference of the azimuthal angles of the two Compton-scattered gammas and studied their dependence on Compton scattering angles θ and on azimuthal resolution ∆φ. For scattering angles around θ1,2 = 82 • , where the maximum modulation is expected, the modulation factors from µ = 0.15 ± 0.01 to µ = 0.27 ± 0.02 have been measured, depending on the azimuthal resolution, which is governed by event topology in the detectors. Analogously, for scattering around θ1,2 = 70 • , modulation factors from µ = 0.12 ± 0.01 to µ = 0.21 ± 0.02 have been obtained. The results show that the measurement of the polarization correlations of annihilation quanta are feasible with compact single-layer, single-side read-out detectors, which may be used to build cost-efficient systems for various applications where gamma-ray polarization information is of interest.

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Investigation of GaGG:Ce with TOFPET2 ASIC Readout for Applications in Gamma Imaging Systems

et al. 2020

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We investigated two detector modules, each consisting of a 8 × 8 matrix of GaGG:Ce crystals with a crystal size of 3 × 3 × 20 mm3 and a 3.2 mm pitch. The light is collected by a 8 × 8 silicon photomultiplier array, with one silicon photomultiplier matching one crystal. The signals are read out and processed using the TOFPET2 ASIC. Performed laboratory tests of the detectors were performed using a 22Na source, where energy and coincidence time resolution with different optical coupling were examined between the crystals and silicon photomultipliers, as well as under various operating voltages. The mean energy resolution of 9.8±0.6% at 511 keV was observed and it was shown that the coincidence time resolution of 384±33 ps could be achieved. The results reassure that the GaGG scintillator is a very promising candidate for the development of imaging systems, in particular, ones utilizing Compton scattering where the energy resolution plays a critical role and a moderate timing performance is acceptable.

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Performance of Scintillation Pixel Detectors with MPPC Read-out and Digital Signal Processing

Cited by 3 publications

References 0 publications

Scintillator Pixel Detectors for Measurement of Compton Scattering

Scintillator Pixel Detectors for Measurement of Compton Scattering

Single-layer Compton detectors for measurement of polarization correlations of annihilation quanta

Investigation of GaGG:Ce with TOFPET2 ASIC Readout for Applications in Gamma Imaging Systems

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