We present a prototype for hybrid Compton and positron emission tomography(PET)imaging aimed at enhancing data utilization and enabling concurrent imaging of multiple radiopharmaceuticals.The prototype comprises two d...We present a prototype for hybrid Compton and positron emission tomography(PET)imaging aimed at enhancing data utilization and enabling concurrent imaging of multiple radiopharmaceuticals.The prototype comprises two detectors that utilize LYSO-SiPM and were available in our laboratory.One detector consists of a 50×50 array of LYSO crystals,each measuring 0.9mm×0.9mm×10mm with 1 mm pitches,whereas the other detector comprises a 25×25 array of LYSO crystals,each measuring 1.9mm×1.9mm×10mm with 2 mm pitches.These detectors are mounted on a rotational stage,which enables them to function as either a Compton camera or a PET detector pair.The 64-channel signals from the SiPMs of each detector are processed through a capacitive multiplexing circuit to yield four position-weighted outputs.Distinct energy windows were used to discriminate Compton events from PET events.Energy resolution and energy-channel relationships were calibrated via multiple sources.The measured average energy resolutions(full widths at half maximum,FWHMs)for the detectors at 511 keV were 17.5%and 15.2%,respectively.The initial experimental results indicate an angular resolution(FWHM)of 8.6◦for the system in Compton imaging mode.A V-shaped tube injected with 18 F solution was clearly reconstructed,which further verified the imaging capabilities of the system in Compton imaging mode.The results of simulation and experimental imaging studies show that the system can detect tumors as small as 1 mm in diameter when working in PET imaging mode.Mouse bone PET imaging was successfully conducted,with the results matching well with the corresponding CT images.This technology holds great potential for advancing the development of physiological function modalities.展开更多
Ultraintense laser–plasma experiments generate a variety of high-energy radiations,including nonlinear inverse Compton scattered(NCS)X-rays,which are expected to be a key experimental observable as we transition into...Ultraintense laser–plasma experiments generate a variety of high-energy radiations,including nonlinear inverse Compton scattered(NCS)X-rays,which are expected to be a key experimental observable as we transition into the quantum electrodynamic plasma regime.However,there is also a high bremsstrahlung X-ray background that reduces our ability to observe NCS X-rays.Previous numerical studies comparing NCS and bremsstrahlung emissions fail to capture the full temporal emission of both processes.We present for the first time two-dimensional particle-in-cell(PIC)and three-dimensional hybrid-PIC EPOCH simulations that capture up to 150 ps of the laser–plasma interaction and directly compare the NCS and bremsstrahlung emissions for a plastic target for intensities of 10^(20)-10^(23)W/cm^(2).We present angular distribution plots where the NCS emission is seen to dominate at intensities greater than 5×10^(21)W/cm^(2)and the target design is seen to successfully divert the bremsstrahlung signal away from the NCS lobe regions,making the experimental observation of nonlinear inverse Compton scattering at lower intensities more likely.展开更多
Extreme ultraviolet(EUV)lithography is crucial for advancing semiconductor manufacturing;however,current EUV light sources,such as laser-produced plasma(LPP),have significant limitations,including low energy-conversio...Extreme ultraviolet(EUV)lithography is crucial for advancing semiconductor manufacturing;however,current EUV light sources,such as laser-produced plasma(LPP),have significant limitations,including low energy-conversion efficiency and debris contamination.Various schemes,including optical free-electron laser undulators,have been studied to generate coherent EUV light.However,optical undulators suffer from limited focal lengths,which pose a significant challenge to achieving a higher gain.In this study,a novel approach is proposed that employs a stretched off-axis paraboloid(sOAP)mirror,thus extending the focus distance to the centimeter range while achieving a well-controlled periodic light field.This enables high-intensity 92-eV EUV sources to exceed 1016/s,as demonstrated in the simulations.The proposed setup provides an efficient and powerful solution for advanced applications including semiconductor lithography.展开更多
基金supported by the National Natural Science Foundation of China(No.12105018)the Beijing Nova Program(Nos.Z211100002121129 and 20230484413)the Beijing Normal University Start-up Grant(No.312232104).
文摘We present a prototype for hybrid Compton and positron emission tomography(PET)imaging aimed at enhancing data utilization and enabling concurrent imaging of multiple radiopharmaceuticals.The prototype comprises two detectors that utilize LYSO-SiPM and were available in our laboratory.One detector consists of a 50×50 array of LYSO crystals,each measuring 0.9mm×0.9mm×10mm with 1 mm pitches,whereas the other detector comprises a 25×25 array of LYSO crystals,each measuring 1.9mm×1.9mm×10mm with 2 mm pitches.These detectors are mounted on a rotational stage,which enables them to function as either a Compton camera or a PET detector pair.The 64-channel signals from the SiPMs of each detector are processed through a capacitive multiplexing circuit to yield four position-weighted outputs.Distinct energy windows were used to discriminate Compton events from PET events.Energy resolution and energy-channel relationships were calibrated via multiple sources.The measured average energy resolutions(full widths at half maximum,FWHMs)for the detectors at 511 keV were 17.5%and 15.2%,respectively.The initial experimental results indicate an angular resolution(FWHM)of 8.6◦for the system in Compton imaging mode.A V-shaped tube injected with 18 F solution was clearly reconstructed,which further verified the imaging capabilities of the system in Compton imaging mode.The results of simulation and experimental imaging studies show that the system can detect tumors as small as 1 mm in diameter when working in PET imaging mode.Mouse bone PET imaging was successfully conducted,with the results matching well with the corresponding CT images.This technology holds great potential for advancing the development of physiological function modalities.
基金the Science and Technology Facilities Council and the Engineering and Physical Sciences Research Council for their funding towards this project,and the continued support of research into QED laser–plasma physicsfunding fromthe Engineering and Physical Sciences Research Council[EP/S022430/1]。
文摘Ultraintense laser–plasma experiments generate a variety of high-energy radiations,including nonlinear inverse Compton scattered(NCS)X-rays,which are expected to be a key experimental observable as we transition into the quantum electrodynamic plasma regime.However,there is also a high bremsstrahlung X-ray background that reduces our ability to observe NCS X-rays.Previous numerical studies comparing NCS and bremsstrahlung emissions fail to capture the full temporal emission of both processes.We present for the first time two-dimensional particle-in-cell(PIC)and three-dimensional hybrid-PIC EPOCH simulations that capture up to 150 ps of the laser–plasma interaction and directly compare the NCS and bremsstrahlung emissions for a plastic target for intensities of 10^(20)-10^(23)W/cm^(2).We present angular distribution plots where the NCS emission is seen to dominate at intensities greater than 5×10^(21)W/cm^(2)and the target design is seen to successfully divert the bremsstrahlung signal away from the NCS lobe regions,making the experimental observation of nonlinear inverse Compton scattering at lower intensities more likely.
基金supported in part by the National Key R&D Program of China(No.2023YFA1606900)the National Natural Science Foundation of China(NSFC)(Nos.12235003 and 12447106).
文摘Extreme ultraviolet(EUV)lithography is crucial for advancing semiconductor manufacturing;however,current EUV light sources,such as laser-produced plasma(LPP),have significant limitations,including low energy-conversion efficiency and debris contamination.Various schemes,including optical free-electron laser undulators,have been studied to generate coherent EUV light.However,optical undulators suffer from limited focal lengths,which pose a significant challenge to achieving a higher gain.In this study,a novel approach is proposed that employs a stretched off-axis paraboloid(sOAP)mirror,thus extending the focus distance to the centimeter range while achieving a well-controlled periodic light field.This enables high-intensity 92-eV EUV sources to exceed 1016/s,as demonstrated in the simulations.The proposed setup provides an efficient and powerful solution for advanced applications including semiconductor lithography.
