Analysis Procedure of the Positronium Lifetime Spectra for the J-PET Detector

Abstract

Positron annihilation lifetime spectroscopy has shown to be a powerful tool to study the nanostructures of porous materials. Positron emission tomograph is a device allowing imaging of metabolic processes e.g. in human bodies. A newly developed device, the Jagiellonian PET will allow positron annihilation lifetime spectroscopy in addition to imaging, thus combining both analyses providing new methods for physics and medicine. In this contribution we present a computer program that is compatible with the Jagiellonian PET software. We compare its performance with the standard program LT 9.0 by using positron annihilation lifetime spectroscopy data from hexane measurements at different temperatures. Our program is based on an iterative procedure, and our fits prove that it performs as good as LT 9.0.

Prospects and Clinical Perspectives of Total-Body PET Imaging Using Plastic Scintillators

“…In the current PET imaging the prompt gamma emitted by b 1 g isotopes as for example, 44 Sc constitutes a source of background. However, high sensitivity, triggerless data acquisition 36 and dedicated data selection algorithms 28,29,37,105,106,110,111 available at J-PET enable efficient registration of triple coincidences (see Fig. 3) corresponding to events with 2 backto-back annihilation photons and prompt gamma.…”

Commissioning of the J-PET detector in view of the positron annihilation lifetime spectroscopy

“…1 with values quoted in reference [18]. Results of the analysis carried out with both programs: J-PET program [45] and LT 9.2 (commonly used for the PAL spectra analysis) [46] for the spectrum measured in J-PET are similar and allow to conclude that the J-PET measuring system is adapted to perform the positron lifetime measurements. The ortho-positronium lifetimes are in good agreement with the results expected on the basis of [18].…”

“…The spectrum shows a sharp maximum corresponding to the annihilation of para-positronium and direct e + e − annihilations as well as long tail corresponding to the decays of ortho-positronium atoms. A superimposed line indicates the fit performed via the dedicated to J-PET fitting procedure described extensively in [45]. The fit function for the positron lifetime distribution is a convolution of the instrumental (resolution) function and the exponential decays, where linear coefficients are connected to probabilities of given components often referred as intensities.…”

“…The fit function for the positron lifetime distribution is a convolution of the instrumental (resolution) function and the exponential decays, where linear coefficients are connected to probabilities of given components often referred as intensities. The exact formula is given in [45]. The lifetime and intensities of annihilations in the Kapton foil were fixed to 0.374 ns and 10% respectively.…”

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

“…J-PET detector possesses the capability to study the lifetime of positronium (Ps) atoms by registering the multiple photons originating from radioactive source and the decays of Ps atoms [11,12]. The positron annihilation lifetime spectroscopy (PALS) is widely being used in characterizing the nanostructures of materials.…”