A new position reconstruction method for position sensitive photomultipliers

Mikeli, M.; Polychronopoulou, Athanasia; Gektin, A.; Giokaris, N.; Karabarbounis, A.; Maintas, D.; Papanicolas, Costas N.; Pedash, V.Yu.; Thanasas, D.; Stiliaris, E.

doi:10.1109/nssmic.2008.4774303

Cited by 10 publications

(6 citation statements)

References 5 publications

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“…analysis we use only full-energy deposition of the 511 keV annihilation γ-rays emitted from a point-like 22 Na-source (2 MBq activity). The position sensitive detector under characterization is sitting in a small movable platform at the bottom of the experimental setup, whereas the collimating system, the 22 Nasource, and the subsidiary detector are placed and fixed on top of a Plexiglas table. The x, y-gantry which drives the movable platform with the detector under study has been upgraded with respect to the one used in our previous work [18].…”

Section: Methodsmentioning

confidence: 99%

“…In the same way, many efforts have been made to determine the z-coordinate of the γ-ray hit or Depth of Interaction (DoI) for single-ended read detectors [9,17,19,20,21,22,23,24,25,26]. It is expected that, from the nature of the problem, much higher sensitivity and precision is achieved in the x,y plane than in its perpendicular axis because the DoI is deduced from the second moment of the light distribution registered by the SiPM.…”

Section: Introductionmentioning

confidence: 99%

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Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

Balibrea-Correa,

Lerendegui-Marco,

Babiano

et al. 2020

Preprint

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We investigate five different models to reconstruct the 3D γ-ray hit coordinates in five large LaCl 3 (Ce) monolithic crystals optically coupled to pixelated silicon photomultipliers. These scintillators have a base surface of 50 × 50 mm 2 and five different thicknesses, from 10 mm to 30 mm. Four of these models are analytical prescriptions and one is based on a Convolutional Neural Network. Average resolutions close to 1-2 mm fwhm are obtained in the transverse crystal plane for crystal thicknesses between 10 mm and 20 mm using analytical models. For thicker crystals average resolutions of about 3-5 mm fwhm are obtained. Depth of interaction resolutions between 1 mm and 4 mm are achieved depending on the distance of the interaction point to the photosensor surface. We propose a Machine Learning algorithm to correct for linearity distortions and pin-cushion effects. The latter allows one to keep a large field of view of about 70-80% of the crystal surface, regardless of crystal thickness. This work is aimed at optimizing the performance of the so-called Total Energy Detector with Compton imaging capability (i-TED) for time-of-flight neutron capture cross-section measurements.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

Balibrea-Correa,

Lerendegui-Marco,

Babiano

et al. 2020

Preprint

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“…The four output signals and the corresponding reconstructed coordinates (X RC , Y RC ) can be tabulated using the described model and equations (7), (8) and (4). As a result, the dependence of X RC (or of Y RC ) on the nominal position P x (or on P y ) can be studied for different values of the parameters s 1 , s 2 and A 1 /A 2 .…”

Section: Inverse Methodsmentioning

confidence: 99%

“…The proposed model for ISR technique as described in [4], parameterizes the incident light with the sum of two Gaussian distributions G 1 and G 2 given by the Equations (5). The charge of the i th wire is calculated through the charge density integration along the specific wire using Equations (6).…”

Section: Model Descriptionmentioning

confidence: 99%

An analytical position correction algorithm for γ-Camera planar images from resistive chain readouts

Thanasas

Georgiou

Giokaris

et al. 2009

2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)

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The charge limitation for peripheral Field Of View (FOV) events detected by the most commonly used Position Sensitive Photomultiplier Tubes (PSPMTs) results to spatial distortions and non-uniformities of the obtained planar images. These effects can be corrected with newly developed sophisticated techniques operating on the charge signals from the individual wires of the multi-anode systems. However, a similar algorithmic approach for the simple case, where the resistive chain readout technique is used and, consequently, the original charge distribution information is lost, is not applicable. In this work the development of a new method to eliminate these distortion effects in the planar images for Ȗ-Camera systems based on resistive chain techniques is presented. The proposed model, which incorporates an a priori knowledge of three parameters related to light diffusion inside the scintillation crystal in use, provides an accurate, analytically calculated estimate of the spatial correction as a function of the primary reconstructed planar position from the resistive chain signals. This algorithm can be used online on an event-by-event basis and can be applied to both, homogeneous and pixelated crystals.

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“…Για το σκοπό ελήφθησαν πειραματικά δεδομένα με ακτινοβόληση των διαφόρων κρυστάλλων του εργαστηρίου τοποθετημένους στο σύστημα του R2486-01 HAMAMATSU φωτοπολλαπλασιαστή ο οποίος καταγράφει τις τιμές και των 8Χ+8Υ φορτίων. Από τα δεδομένα αυτά υπολογίστηκε η παράμετρος s 1 (με τη διαδικασία του αντίστροφου fit που περιγράφθηκε σε προηγούμενη παράγραφο) που είναι το εύρος της γκαουσιανής κατανομής των οπτικών φωτονίων για διάφορα είδη και πάχη κρυστάλλων[MIK08]. Στο Σχήμα 6.22 φαίνονται οι γραφικές παραστάσεις του s 1 για διάφορα πάχη και ενέργειες των γ-φωτονίων για τους κρυστάλλους CsI(Tl) (αριστερά) και BGO (δεξιά).…”

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Ανάπτυξη Τομοσπινθηρογραφικού Συστήματος Υψηλής Ευαισθησίας Και Διακριτικής Ικανότητας

Θανασάς¹

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Στην Μονοφωτονική Τομοσπινθηρογραφία τύπου SPECT (Single Photon Emission Computed Tomography) η λήψη προβολικών εικόνων γίνεται με την βοήθεια γ-Κάμερα, η φυσική αρχή λειτουργίας της οποίας παραμένει αμετάβλητη εδώ και μισό σχεδόν αιώνα. Η εκπόνηση της παρούσας Διδακτορικής Διατριβής είχε σαν κεντρικό στόχο την ανάπτυξη ενός σύγχρονου τέτοιου συστήματος μικρού πεδίου αλλά με υψηλή ευαισθησία και διακριτική ικανότητα, βασισμένου σε μοντέρνες τεχνικές. Παράλληλα με την μελέτη των επιμέρους συνθετικών μερών της γ-Κάμερα (κατευθυντήρας, κρύσταλλοι σπινθηρισμού, χωρικά ευαίσθητος φωτοπολλαπλασιαστής) έγινε ενδελεχής μελέτη του συστήματος σε επίπεδο προσομοιώσεων με το λογισμικό GEANT4/Gate, έτσι ώστε να επιλεγούν οι καταλληλότεροι σπινθηριστές και να καθοριστούν οι βέλτιστες γεωμετρικές παράμετροι. Αναπτύχθηκαν και εφαρμόστηκαν σειρά από διορθωτικούς αλγορίθμους σε επίπεδο προβολικής εικόνας. Το ολοκληρωμένο εργαστηριακό σύστημα αξιολογήθηκε μέσα από σειρά πειραματικών ελέγχων τόσο σε προβολικό, όσο και σε τομογραφικό επίπεδο και χαρακτηρίζεται από μια χωρική διακριτική ικανότητα καλύτερη του χιλιοστομέτρου.

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A new position reconstruction method for position sensitive photomultipliers

Cited by 10 publications

References 5 publications

Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

An analytical position correction algorithm for γ-Camera planar images from resistive chain readouts

Ανάπτυξη Τομοσπινθηρογραφικού Συστήματος Υψηλής Ευαισθησίας Και Διακριτικής Ικανότητας

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A new position reconstruction method for position sensitive photomultipliers

Cited by 10 publications

References 5 publications

Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

Machine Learning aided 3D-position reconstruction in large LaCl$_{3}$ crystals

An analytical position correction algorithm for &#x03B3;-Camera planar images from resistive chain readouts

Ανάπτυξη Τομοσπινθηρογραφικού Συστήματος Υψηλής Ευαισθησίας Και Διακριτικής Ικανότητας

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An analytical position correction algorithm for γ-Camera planar images from resistive chain readouts