TOT Method for the Disentanglement of Photons in Positron Annihilation Lifetime Spectroscopy

Sharma, Sushil

doi:10.12693/aphyspola.137.130

Cited by 2 publications

(2 citation statements)

References 18 publications

(18 reference statements)

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“…In previous work [ 27 ], a relationship between TOT and energy deposition was established, allowing energy deposition to be directly pruned to reduce the amount of scatter. TOT values can be used as a preliminary criterion to distinguish the annihilation photons from the prompt gamma rays (1275 keV) also emitted by the Na source [ 62 ]. In the standard scanner, only the back-to-back annihilation photons (511 keV) are of interest.…”

Section: Methodsmentioning

confidence: 99%

Efficiency determination of J-PET: first plastic scintillators-based PET scanner

et al. 2023

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Background The Jagiellonian Positron Emission Tomograph is the 3-layer prototype of the first scanner based on plastic scintillators, consisting of 192 half-metre-long strips with readouts at both ends. Compared to crystal-based detectors, plastic scintillators are several times cheaper and could be considered as a more economical alternative to crystal scintillators in future PETs. JPET is also a first multi-photon PET prototype. For the development of multi-photon detection, with photon characterized by the continuous energy spectrum, it is important to estimate the efficiency of J-PET as a function of energy deposition. The aim of this work is to determine the registration efficiency of the J-PET tomograph as a function of energy deposition by incident photons and the intrinsic efficiency of the J-PET scanner in detecting photons of different incident energies. In this study, 3-hit events are investigated, where 2-hits are caused by 511 keV photons emitted in $$e^+e^-$$ e + e - annihilations, while the third hit is caused by one of the scattered photons. The scattered photon is used to accurately measure the scattering angle and thus the energy deposition. Two hits by a primary and a scattered photon are sufficient to calculate the scattering angle of a photon, while the third hit ensures the precise labeling of the 511 keV photons. Results By comparing experimental and simulated energy distribution spectra, the registration efficiency of the J-PET scanner was determined in the energy deposition range of 70–270 keV, where it varies between 20 and 100$$\%$$ % . In addition, the intrinsic efficiency of the J-PET was also determined as a function of the energy of the incident photons. Conclusion A method for determining registration efficiency as a function of energy deposition and intrinsic efficiency as a function of incident photon energy of the J-PET scanner was demonstrated. This study is crucial for evaluating the performance of the scanner based on plastic scintillators and its applications as a standard and multi-photon PET systems. The method may be also used in the calibration of Compton-cameras developed for the ion−beam therapy monitoring and simultaneous multi-radionuclide imaging in nuclear medicine.

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Section: Methodsmentioning

confidence: 99%

Efficiency determination of J-PET: first plastic scintillators-based PET scanner

et al. 2023

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“…The hit time, on the other hand, was calculated as the average of the measured times of the light signals [37]. In J-PET, the data are stored in triggerless mode [38,39] and Time Over Threshold (TOT) is approached as measure of energy depositions [40,41]. In addition, a special framework was developed to analyse the stored data [42].…”

Section: Jpet As Compton Polarimeter To Measure Relative Polarizationmentioning

confidence: 99%

Decoherence puzzle in measurements of photons originating from electron-positron annihilation

Sharma¹,

Kumar²,

Moskal³

2022

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Entanglement of photons originating from the electron-positron annihilation has not been proven experimentally. Though the independent experiments performed so far unanimously confirm that correlation between the linear polarizations of back-to-back photons from the electron-positron annihilation is consistent with the assumption that these photons are entangled in polarization. Yet, unexpectedly, recent experiments differ as regards the correlation of polarization direction of back-to-back photons after the decoherence induced by scattering of one of these photons on the electron in the scattering material. In one of the experiments the correlation before and after the decoherence of the photon state is the same and in the other experiment the scattering of one photon leads to a significant decrease of this correlation. Here we discuss this puzzle. The separable states were ensured by forcing one of the annihilation photons through prior scattering before the Compton kinematics-based measurement of the polarization correlation. A comparison between the experimental setups used for the different measurements and the results obtained are briefly discussed, highlighting the parameters that are important for performing such measurements. Finally, the main features of the J-PET detector are presented with the schemes for performing similar measurements so that the results can be used as conclusive remarks for solving this puzzle. Solving of these puzzle will have crucial consequences for basic studies of entanglement and also for the proposed application of polarisation of photons in positron emission tomography. In case if the correlation of polarisation of back-to-back photons from the electron-positron annihilation is the same before and after the scattering of these photons, then it will not be useful for the reduction of the scatter fraction in PET diagnostics.

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TOT Method for the Disentanglement of Photons in Positron Annihilation Lifetime Spectroscopy

Cited by 2 publications

References 18 publications

Efficiency determination of J-PET: first plastic scintillators-based PET scanner

Efficiency determination of J-PET: first plastic scintillators-based PET scanner

Decoherence puzzle in measurements of photons originating from electron-positron annihilation

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