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SUMMARY:Development of Microdosimetric Detectors for Radiobiology in Hadro
 n Therapy
DTSTART:20261015T103000Z
DTEND:20261015T120000Z
DTSTAMP:20261008T043800Z
UID:indico-event-2247@indico.lip.pt
DESCRIPTION:Speakers: Cristiana Rodrigues\n\nMicroscale characterization o
 f radiation fields in hadron therapy requires detectors capable of combini
 ng high dose sensitivity with high spatial resolution. This work explored 
 two approaches to develop cost-effective materials for active and passive 
 dosimetry in radiobiology: production of micrometric plastic optical fiber
 s (mPOFs) for active dosimeters\; and growth of α-Al2O3 crystals for lumi
 nescence dosimetry and particle tracking. \nFiber-based microdosimetry re
 quires micrometer-thick fibers with dimensions close to typical cell sizes
 . However\, the smallest mPOFs available have a 200 μm diameter. Three pr
 oduction methods were studied with an in-house setup: electrospinning\, me
 lt-electrospinning\, and melt-spinning. Melt-spinning delivered highly ali
 gned fibers down to 80 μm. Process reproducibility was acceptable\, with 
 diameter tolerances within 30% and optical transmission comparable to that
  of commercial POFs. \nLuminescence-based detectors are particularly attr
 active as thermoluminescence (TL) and optically stimulated luminescence (O
 SL) provide high low-dose sensitivity\, whereas fluorescent nuclear track 
 detectors (FNTDs) enable visualization of individual charged-particle trac
 ks with subcellular resolution. α-Al2O3 single crystals were grown by the
  flux-evaporation method\, with a Li2O–MoO3 system. Standard C\, {C\,Mg}
  doping and novel combinations {C\,Zn}\, {C\,Ti}\, {C\,Mn}\, {C\,Ce} and {
 C\,Si} were investigated. The radiation-induced luminescence (30 mGy – 1
 5 Gy) to 90Sr/90Y β-radiation were studied as a function of precursor pur
 ity and doping. Increasing MoO3 and Al2O3 precursor purity enhanced TL and
  OSL intensity by up to 67× and 14×\, respectively\, and significantly i
 mproved low-dose sensitivity. {C\,Mg} and {C\,Mn(IV)} yielded the stronges
 t TL/OSL responses\, with up to a twofold TL and fourfold OSL intensity in
 crease relative to undoped crystals. The FNTD potential of flux-grown crys
 tals was assessed through 12C-ion irradiations conducted at the Heidelberg
  Ion-Beam Therapy Center (HIT\, Germany). Both undoped and {C\,Mg}-doped c
 rystals exhibited ion tracks. {C\,Mg} samples showed improved performance\
 , with approximately 50% detection of expected tracks\, although remaining
  less sensitive than commercial Czochralski-grown FNTDs. These results dem
 onstrate the potential of flux-grown Al2O3 as a low-cost material for lumi
 nescence dosimetry and track detection\, motivating further optimization o
 f crystal growth.\n\nhttps://indico.lip.pt/event/2247/
LOCATION:LIP-Lisboa/3-311 - Sala de Seminários (LIP Lisboa)
URL:https://indico.lip.pt/event/2247/
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