Publicação
Characterisation and functional test of the full readout chain of a microdosimeter using scintillating plastic optical fibres
| datacite.subject.fos | Ciências Naturais::Ciências Físicas | pt_PT |
| dc.contributor.advisor | Saraiva, João Gentil Mendes | |
| dc.contributor.advisor | Evans, Guiomar Gaspar de Andrade | |
| dc.contributor.author | Santos, Matilde Maria Sobreiro | |
| dc.date.accessioned | 2022-07-12T13:27:07Z | |
| dc.date.available | 2022-07-12T13:27:07Z | |
| dc.date.issued | 2022 | |
| dc.date.submitted | 2021 | |
| dc.description | Tese de Mestrado Integrado, Engenharia Física, 2022, Universidade de Lisboa, Faculdade de Ciências | pt_PT |
| dc.description.abstract | Instruments with a high spatial resolution are necessary to measure dosimetric quantities at a cellular level in order to have a better delineation of treatment plans in radiotherapy. The work here described is within a project aiming to develop a new detector capable of measuring real time absorbed dose with sub-millimetre resolution. The device is constructed using juxtaposed scintillating plastic optical fibres (SPOF) readout by a multi-anode photomultiplier (MAPMT, Hamamatsu H8500D) and a data acquisition (DAQ) system. In this thesis a first validation of the full readout chain is done, going through the characterisation of the different elements composing this detector. Using a dedicated test bench SPOFS (Kuraray SCSF-78) of 1 mm and 0.5 mm were optically characterised, measuring basic properties, such as light yields and attenuation lengths, before measuring the crosstalk between juxtaposed optical fibres. Methods of analysis were designed to compare the signal from an isolated and ribbon SPOF. Next, the MAPMT’s key characteristics were studied using a UV-LED exciting SPOF, to guide the light to individual MAPMT cells, and a picoammeter as a readout system. Concerning the assembly of the MAPMT in a detector assembly, the ideal conditions to achieve a light tight setup were evaluated. The full readout chain was completed by including a costumed DAQ board. Pulsed LEDs were firstly used to evaluate main limitations in signal response of the readout chain. Radioactive sources were then used to test the sensibility to particles (betas, gammas and alphas). In terms of results, the crosstalk study needs further revision, specially quantifying its value. The MAPMT’s performance was characterised and validated, whereas the DAQ board observed saturation and response to particles needs more understanding. However, the integration of the three elements of the microdosimeter was achieved and could be implemented into a first prototype. | pt_PT |
| dc.identifier.tid | 203219422 | pt_PT |
| dc.identifier.uri | http://hdl.handle.net/10451/53766 | |
| dc.language.iso | eng | pt_PT |
| dc.subject | Terapia com protões | pt_PT |
| dc.subject | Microdosimetria | pt_PT |
| dc.subject | Fibras ópticas cintilantes de plástico | pt_PT |
| dc.subject | Fotomultiplicador multi-ânodo | pt_PT |
| dc.subject | Placa de aquisição de dados | pt_PT |
| dc.subject | Teses de mestrado - 2022 | pt_PT |
| dc.title | Characterisation and functional test of the full readout chain of a microdosimeter using scintillating plastic optical fibres | pt_PT |
| dc.type | master thesis | |
| dspace.entity.type | Publication | |
| rcaap.rights | openAccess | pt_PT |
| rcaap.type | masterThesis | pt_PT |
| thesis.degree.name | Mestrado Integrado em Engenharia Física | pt_PT |