Further investigations of a radiation detector based on ionization-induced modulation of optical polarization

Wang, Yuli; Tao, Li; Abbaszadeh, Shiva; Levin, Craig S.

doi:10.1088/1361-6560/abe027

Cited by 7 publications

(7 citation statements)

References 34 publications

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“…We measured the profile of steady-state electric field dependence on the incident nearinfrared light photon energy at room temperature (300 K) by a cross-polarizers technique exploiting the Pockels effect of studied crystals [21][22][23]. The samples of dimensions of 5 × 5 × 2 mm 3 were cut from the same single crystals as those used for microhardness studies.…”

Section: Methodsmentioning

confidence: 99%

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

et al. 2021

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We studied the spectral dependence of the Vickers microhardness HV0.025 of CdZnTe and CdZnTeSe samples upon illumination and found out that it increases over the entire applied spectral range of 1540–750 nm. We also found out that the photoconductivity and microhardness are correlated. We observed changes in the correlation diagram (change of slope and an abrupt change of HV0.025 at several wavelengths of the illuminating light). Based on measurements of the relative changes of the space charge upon illumination using the Pockels effect, we suggest that the observed spectral dependence of positive photoplastic effect in CdZnTe and CdZnTeSe can be explained by the trapping of photoinduced electrons and holes, which affects the motion of the partial dislocations. The underlying physical explanation relies on the assumption that reconstructed bonds break before dislocation glide.

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Section: Methodsmentioning

confidence: 99%

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

et al. 2021

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“…The experimental set up for utilizing the Pockels effect involves a polarized probe laser pumped through a crystal with an applied bias to another polarizer. The light is then focused onto a photodiode via a lens [96,97]. The refractive index of a Pockels cell is found from Eq.…”

Section: Optical Property Modulationmentioning

confidence: 99%

“…where n(E) is the refractive index of the Pockels cell, E is the applied electric field, n 0 is the refractive index without applying an electric field, and γ is the Pockels effect coefficient [96,97]. In addition to the modification of the refractive index, the transmitted light intensity is also dependent on the applied electric field.…”

Section: Optical Property Modulationmentioning

confidence: 99%

“…The photodiode can then measure the change in transmitted light to measure the modulation of the optical properties of the detector crystal [95][96][97]. This method has been completed with various materials, such as cadmium telluride (CdTe) [96][97][98], bismuth silicate [98], yttrium aluminum garnet (YAG) [99], lead bismuth gallium (PbBiGa) [98], and lithium niobate (LiNbO 3 ) [96]. Empirical analysis has predicted improvement in the timing resolution on the order of 1 ps [99].…”

Section: Optical Property Modulationmentioning

confidence: 99%

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State-of-the-art challenges and emerging technologies in radiation detection for nuclear medicine imaging: A review

Enlow

Abbaszadeh

2023

Front. Phys.

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Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are established medical imaging modalities that have been implemented for decades, but improvements in detector design and camera electronics are needed for advancement of both imaging technologies. Detectors are arguably the most important aspect of the systems. Similar to SPECT, PET typically relies on indirect conversion of gamma radiation via scintillators coupled with photosensors used to convert optical photons produced by the scintillator into an electrical signal. PET detectors are defined by their energy resolution, timing resolution, and spatial resolution, all of which affect and determine the image quality. Improvements in energy resolution have been shown by increasing the brightness of the scintillator utilizing materials like cerium bromide (CeBr3) or switching to a direct conversion detector, such as cadmium zinc telluride (CZT) or thallium bromide (TlBr). Timing resolution for PET is a focal point of the current research. Improving the timing resolution improves the signal-to-noise of the PET system and is integral to the implementation of time-of-flight PET. By utilizing novel configurations, such as side readouts on scintillators, timing resolution has been improved dramatically. Similarly, metascintillators, which use complex combinations for the scintillator material, have also shown improvements to the timing resolution. Additional research has focused on using Cherenkov light emission in scintillators to further improve the timing resolution. Other research is focused on using convolutional neural networks and other signal processing to enhance timing resolution. Lastly, aside from acollinearity and positron range, spatial resolution is impacted by the PET detector, therefore improving the intrinsic spatial resolution of the detector will allow for smaller features to be imaged. One method for improving the spatial resolution is to use unique configurations with layered scintillators. Additionally, monolithic scintillators have also been shown to have reduced spatial resolution. The future for both SPECT and PET image system advancement will depend on continued development of the detectors via many different pathways including materials, signal processing, physics, and novel configurations. In this review article, we will discuss challenges and emerging technologies for state-of-the-art radiation detectors utilized in PET and SPECT.

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“…The coincidence timing resolution (CTR) of the PET detector is influenced by various factors such as scintillator properties, structure, size, surface roughness, rise time, decay time, photosensor device, readout circuit, and threshold voltage [ 8 , 9 , 10 , 11 , 12 , 13 ]. Much research has been carried out on detector structure, timing measurement, and compensation algorithms [ 11 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. J.…”

Section: Introductionmentioning

confidence: 99%

Optical Simulation and Experimental Assessment with Time–Walk Correction of TOF–PET Detectors with Multi-Ended Readouts

Xie

Zhu

Zhang

et al. 2021

Sensors

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As a commonly used solution, the multi-ended readout can measure the depth-of-interaction (DOI) for positron emission tomography (PET) detectors. In the present study, the effects of the multi-ended readout design were investigated using the leading-edge discriminator (LED) triggers on the timing performance of time-of-flight (TOF) PET detectors. At the very first, the photon transmission model of the four detectors, namely, single-ended readout, dual-ended readout, side dual-ended readout, and triple-ended readout, was established in Tracepro. The optical simulation revealed that the light output of the multi-ended readout was higher. Meanwhile, the readout circuit could be triggered earlier. Especially, in the triple-ended readout, the light output at 0.5 ns was observed to be nearly twice that of the single-ended readout after the first scintillating photon was generated. Subsequently, a reference detector was applied to test the multi-ended readout detectors that were constructed from a 6 × 6 × 25 mm3 LYSO crystal. Each module is composed of a crystal coupled with multiple SiPMs. Accordingly, its timing performance was improved by approximately 10% after the compensation of fourth-order polynomial fitting. Finally, the compensated full-width-at-half-maximum (FWHM) coincidence timing resolutions (CTR) of the dual-ended readout, side dual-ended readout, and triple-ended readout were 216.9 ps, 231.0 ps, and 203.6 ps, respectively.

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Further investigations of a radiation detector based on ionization-induced modulation of optical polarization

Cited by 7 publications

References 34 publications

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

State-of-the-art challenges and emerging technologies in radiation detection for nuclear medicine imaging: A review

Optical Simulation and Experimental Assessment with Time–Walk Correction of TOF–PET Detectors with Multi-Ended Readouts

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