(Wednesday, 8/1/2018) 10:00 AM - 10:30 AM
Room: Exhibit Hall | Forum 3
Purpose: The development of multi-point plastic scintillation detectors has proven the strength of combining several scintillators in a single detector. This study intends to extend this concept from point-like detectors to 3D measurement devices using multiple scintillators with different emission spectrum.
Methods: Two cubic scintillators with different emission spectrum, EJ-212 and EJ-260 (Eljen technology), were irradiated at 6 MV in a water tank and imaged with a polychromatic CCD camera. The setup was irradiated by two parallel opposed beams to create a homogeneous dose deposition. The RGB channels of the camera were then used as three spectrum measuring wavebands. Prior kV measurements were performed to obtain the individual response of each scintillating element. The multispectral formalism was then used to decouple the signal from our three luminescence sources, namely EJ-212’s blue emission, EJ-260’s green emission and Cerenkov signal produced within water. Finally, the signal separation was studied in three different setups: (1) EJ-260 in front of EJ-212, (2) EJ-260 behind EJ-212 and (3) EJ-212 next to EJ-260.
Results: The multispectral formalism was applied to extract the dose deposited to each luminescent material and doses were normalized to reference individual scintillator signal measurements. Throughout the different setups studied, the dose measured by Cherenkov signal varied by less than 1%. Setup 3 resulted in dose differences of 1.75% and 0.36% for EJ-212 and EJ-260, respectively. Setups 1 and 2, however, led to an increase of signal due to EJ-260’s photo-excitation by EJ-212’s emission. Setup 1 showed dose differences of 7% and 3% for EJ-212 and EJ-260 while setup 2 resulted in a 46% dose increase in EJ-260.
Conclusion: This work demonstrates the possibility of using the multispectral formalism for 3D signal separation and reveals the need to consider photoexcitation when designing a detector with multiple scintillators.
Funding Support, Disclosures, and Conflict of Interest: The presenting author is financially supported by a doctoral scholarship from the Fonds de recherche du Quebec - Nature et technologies (FRQNT) and also acknowledges partial support from the CREATE Medical Physics Research Training Network grant of the NSERC (grant number: 432290).
Keywords
3D, Radiation Dosimetry, Scintillators
Taxonomy
TH- Radiation dose measurement devices: scintillators
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