The combination of time domain diffuse optics (TD-DO) with time-domain Raman spectroscopy (TD-DIRS), being both non-intrusive optical techniques, is a new field of research aimed at deep tissue diagnosis. For a diffusive media, which is the case of biological samples, TD-DIRS can provide molecular-specific information by analysing the Raman spectrum built by wavelength shifted re-emitted photons, while TD-DO provides depth probing by extracting information about medium’s properties (such as absorption and scattering coefficients, respectively linked to its composition and microstructure) from the Distribution of Time-of-Flight (DOTF) of the re-emitted photons. To apply TD-DO, time-resolved single-photon detectors are needed for Time-Correlated Single-Photon Counting (TCSPC), while for TD-DIRS, a high filling factor array of about 100 time-resolved single-photon detectors is needed to receive whole range of shifted wavelengths. This thesis focuses on the development of a such detection system, from the selection of the new generation Silicon Photomultipliers (SiPM) as single-photon detectors to be used to the design and implementation in PCB (Printed Circuit Board) of the detector array with its respective front-end circuit, respecting both optical and electrical project specifications. The second part of the thesis focuses on the characterization of the implemented 128-channel SiPM array to prove its robustness and provide the device’s key parameters for both the targeted techniques, such as the timing resolution and dark count rate.
La combinazione dell’ottica diffusa nel dominio del tempo (TD-DO) con spettroscopia Raman nel dominio del tempo (TD-DIRS), essendo entrambe tecniche ottiche non invasive, è un nuovo campo di ricerca mirato alla diagnosi dei tessuti in profondità. Per un mezzo diffusivo come nel caso dei campioni biologici, la TD-DIRS può fornire informazioni molecolari specifiche analizzando lo spettro dei fotoni riemessi con lunghezza d'onda spostata, mentre la TD-DO fornisce informazioni sulle proprietà del mezzo (come coefficienti di assorbimento e scattering, rispettivamente legati alla sua composizione e alla microstruttura) dalla Distribuzione del tempo di volo (DOTF) dei fotoni riemessi. Per l’uso della TD-DO, sono necessari rivelatori di singolo fotone risolti in tempo per il conteggio con tecniche di Time-Correlated Single-Photon Counting (TCSPC), mentre per la TD-DIRS, è necessario un array di circa 100 rivelatori di singolo fotone risolti in tempo ad elevata concentrazione per ricevere l'intera gamma di lunghezze d'onda. Questa tesi si concentra sullo sviluppo di un tale sistema di rilevazione, dalla selezione di fotomoltiplicatori al silicio (SiPM) di nuova generazione come rivelatori di singoli fotoni da utilizzare alla progettazione e implementazione in PCB (Printed Circuit Board) dell'array con il rispettivo circuito front-end, rispettando sia le specifiche ottiche che elettriche del progetto. La seconda parte della tesi si concentra sulla caratterizzazione dell'array SiPM a 128 canali implementato per dimostrare la sua robustezza e fornire i parametri chiave del dispositivo per entrambe le applicazioni di riferimento, come la risoluzione temporale e il tasso di conteggi di buio.
Development and characterization of a 128-channel SiPM-based time-domain diffuse Raman spectroscopy array for deep tissue diagnostics
YE, XINQIU
2023/2024
Abstract
The combination of time domain diffuse optics (TD-DO) with time-domain Raman spectroscopy (TD-DIRS), being both non-intrusive optical techniques, is a new field of research aimed at deep tissue diagnosis. For a diffusive media, which is the case of biological samples, TD-DIRS can provide molecular-specific information by analysing the Raman spectrum built by wavelength shifted re-emitted photons, while TD-DO provides depth probing by extracting information about medium’s properties (such as absorption and scattering coefficients, respectively linked to its composition and microstructure) from the Distribution of Time-of-Flight (DOTF) of the re-emitted photons. To apply TD-DO, time-resolved single-photon detectors are needed for Time-Correlated Single-Photon Counting (TCSPC), while for TD-DIRS, a high filling factor array of about 100 time-resolved single-photon detectors is needed to receive whole range of shifted wavelengths. This thesis focuses on the development of a such detection system, from the selection of the new generation Silicon Photomultipliers (SiPM) as single-photon detectors to be used to the design and implementation in PCB (Printed Circuit Board) of the detector array with its respective front-end circuit, respecting both optical and electrical project specifications. The second part of the thesis focuses on the characterization of the implemented 128-channel SiPM array to prove its robustness and provide the device’s key parameters for both the targeted techniques, such as the timing resolution and dark count rate.| File | Dimensione | Formato | |
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2024_12_Ye.pdf
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Descrizione: Final version of thesis
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https://hdl.handle.net/10589/231037