In order to meet the increasing demands of modern radiotherapy, real time in-vivo dose measurement has recently attracted significant attention. A small, flexible optical fiber radiation dosimeter, with high signal-to...In order to meet the increasing demands of modern radiotherapy, real time in-vivo dose measurement has recently attracted significant attention. A small, flexible optical fiber radiation dosimeter, with high signal-to-noise ratio (SNR) that employs inorganic scintillator materials is presented. In this paper, some properties are investigated under special conditions, such as saturation properties when the intensity of the X-Ray is increased and the influence of the temperature of the environment. These properties are important to practical considerations if the sensor is to be successfully deployed in-vivo.展开更多
To measure the pulsed neutron of a pulsed fission source,an organic scintillation fiber(OSF) detector with separation structure has been designed.The proposed detector employs UV optical fibers as the light guide,and ...To measure the pulsed neutron of a pulsed fission source,an organic scintillation fiber(OSF) detector with separation structure has been designed.The proposed detector employs UV optical fibers as the light guide,and the sensitive region of the detector is composed of a linear array of OSFs,which are individually connected to the optical fibers.The other end of the light guide is coupled to a photomultiplier tube.The key properties of the device including the energy response,time response,neutron sen-sitivity,and radiation effect of the optical fiber were studied.The detector has a relatively high n/? sensitivity ratio,which in-creases as the diameter of the OSF decreases,and ratios greater than 10 could be achieved when the diameter of the OSF is less than 0.3 mm.The sensitivity of the detector to neutrons ranges from 10?14 to 10?20 C cm2/n,and has a response time of 3 ns(FWHM).The proposed detector is also highly flexible.For instance,the probe can be set close to the source,while the PMT can be placed far away from radiation,allowing easy shielding.Due to these characteristics,pulsed fission neutrons in the vi-cinity of the source can be accurately measured.展开更多
We present a liquid refractive index （RI） sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range o...We present a liquid refractive index （RI） sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range of 1.333-1.473, the sensor has a good linear loss （dB） response to the liquid RI in the micro-holes and a high sensitivity of 18 dB/RIU approximately. The experimental results are explained with the mode of the refrac- tion loss caused by the hole core interface and connection loss caused by the gap of the holes. The sensor has many advantages including high sensitivity and low cost.展开更多
Radiation therapy,which uses X-rays to destroy or injure cancer cells,has become one of the most important modalities to treat the primary cancer or advanced cancer.High resolution,water equivalent and passive X-ray d...Radiation therapy,which uses X-rays to destroy or injure cancer cells,has become one of the most important modalities to treat the primary cancer or advanced cancer.High resolution,water equivalent and passive X-ray dosimeters are highly desirable for developing quality assurance（QA）systems for novel cancer therapy like microbeam radiation therapy（MRT）which is currently under development.Here we present the latest developments of high spatial resolution scintillator based photonic dosimeters,and their applications to clinical external radiation beam therapies：specifically high energy linear accelerator（LINAC）photon beams and low energy synchrotron photon beams.We have developed optical fiber dosimeters with spatial resolutions ranging from 50 to 500 gm and tested them with LINAC beams and synchrotron microbeams.For LINAC beams,the fiberoptic probes were exposed to a 6 MV,10 cm by 10 cm X-ray field and,the beam profiles as well as the depth dose profiles were measured at a source-to-surface distance（SSD）of 100 cm.We have also demonstrated the possibility for temporally separating Cherenkov light from the pulsed LINAC scintillation signals.Using the 50 μm fiber probes,we have successfully resolved the microstructures of the microbeams generated by the imaging and medical beamline（IMBL）at the Australian Synchrotron and measured the peak-to-valley dose ratios（PVDRs）.In this paper,we summarize the results we have achieved so far,and discuss the possible solutions to the issues and challenges we have faced,also highlight the future work to further enhance the performances of the photonic dosimeters.展开更多
文摘In order to meet the increasing demands of modern radiotherapy, real time in-vivo dose measurement has recently attracted significant attention. A small, flexible optical fiber radiation dosimeter, with high signal-to-noise ratio (SNR) that employs inorganic scintillator materials is presented. In this paper, some properties are investigated under special conditions, such as saturation properties when the intensity of the X-Ray is increased and the influence of the temperature of the environment. These properties are important to practical considerations if the sensor is to be successfully deployed in-vivo.
文摘To measure the pulsed neutron of a pulsed fission source,an organic scintillation fiber(OSF) detector with separation structure has been designed.The proposed detector employs UV optical fibers as the light guide,and the sensitive region of the detector is composed of a linear array of OSFs,which are individually connected to the optical fibers.The other end of the light guide is coupled to a photomultiplier tube.The key properties of the device including the energy response,time response,neutron sen-sitivity,and radiation effect of the optical fiber were studied.The detector has a relatively high n/? sensitivity ratio,which in-creases as the diameter of the OSF decreases,and ratios greater than 10 could be achieved when the diameter of the OSF is less than 0.3 mm.The sensitivity of the detector to neutrons ranges from 10?14 to 10?20 C cm2/n,and has a response time of 3 ns(FWHM).The proposed detector is also highly flexible.For instance,the probe can be set close to the source,while the PMT can be placed far away from radiation,allowing easy shielding.Due to these characteristics,pulsed fission neutrons in the vi-cinity of the source can be accurately measured.
文摘We present a liquid refractive index （RI） sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range of 1.333-1.473, the sensor has a good linear loss （dB） response to the liquid RI in the micro-holes and a high sensitivity of 18 dB/RIU approximately. The experimental results are explained with the mode of the refrac- tion loss caused by the hole core interface and connection loss caused by the gap of the holes. The sensor has many advantages including high sensitivity and low cost.
文摘Radiation therapy,which uses X-rays to destroy or injure cancer cells,has become one of the most important modalities to treat the primary cancer or advanced cancer.High resolution,water equivalent and passive X-ray dosimeters are highly desirable for developing quality assurance（QA）systems for novel cancer therapy like microbeam radiation therapy（MRT）which is currently under development.Here we present the latest developments of high spatial resolution scintillator based photonic dosimeters,and their applications to clinical external radiation beam therapies：specifically high energy linear accelerator（LINAC）photon beams and low energy synchrotron photon beams.We have developed optical fiber dosimeters with spatial resolutions ranging from 50 to 500 gm and tested them with LINAC beams and synchrotron microbeams.For LINAC beams,the fiberoptic probes were exposed to a 6 MV,10 cm by 10 cm X-ray field and,the beam profiles as well as the depth dose profiles were measured at a source-to-surface distance（SSD）of 100 cm.We have also demonstrated the possibility for temporally separating Cherenkov light from the pulsed LINAC scintillation signals.Using the 50 μm fiber probes,we have successfully resolved the microstructures of the microbeams generated by the imaging and medical beamline（IMBL）at the Australian Synchrotron and measured the peak-to-valley dose ratios（PVDRs）.In this paper,we summarize the results we have achieved so far,and discuss the possible solutions to the issues and challenges we have faced,also highlight the future work to further enhance the performances of the photonic dosimeters.
