The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detec...The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detected using a low-leakage silicon drift detector(SDD),which is cooled to-30℃.The SDD output is processed using two parallel shaping amplifiers with peaking times of 315 ns and 65 ns.The amplifiers are designed using two-pole multiple-feedback active low-pass filters optimized to achieve a Bessel response.The differential output of the shaping amplifier generates a bipolar signal.The phase of the differential stage is tuned to ensure zero crossing corresponding to the peak of the shaping amplifier.A high-speed switch is inserted between the shaping amplifier and the peak-hold capacitor,and the peak value is maintained by turning off the switch.Fast and slow peak-hold circuits share a common ADC via time-division multiplexing.Both peak values are sampled for space-background rejection.Traditional pile-up detection methods cannot distinguish pulses that overlap in a fast channel.In this study,the differential of the“fast shaping”is selected,enabling the distinction of events separated by as little as 65ns,which is crucial for solar flare detection.The energy resolution is measured to be 138 eV at 5.90 keV.The centroid drift is less than 3.6 eV between-5℃ and 20℃.Compared with other solar X-ray instruments,this study demonstrates improved energy resolution with a lower peaking time,indicating a higher solar flare detection capability.展开更多
Based on the RXTE observations of Sco X-1,we identified a clear dichotomy in the behavior of its X-ray crosscorrelation functions(CCFs)which is possibly associated with two different radio jet ejection events.Twenty s...Based on the RXTE observations of Sco X-1,we identified a clear dichotomy in the behavior of its X-ray crosscorrelation functions(CCFs)which is possibly associated with two different radio jet ejection events.Twenty six observations display asymmetric CCFs of low correlation coefficients with soft or hard delays of a few hundred seconds along with no oscillation feature in the power density spectrum associated with horizontal branch/hard apex.All the observations belonging to NB/FB have symmetric CCFs with NBO/NBO+HBO/FBO in the PDS.Based on radio observations,two different types of jets were associated with Sco X-1 i.e.,ballistic radio jets and an ultra-relativistic flow(URF).We noted that asymmetric CCFs with delays were connected with ballistic or lobe radio jets and symmetric CCFs with URFs in Sco X-1.We interpret these findings as evidence of two different states of the inner accretion disk.We propose that the launch of a ballistic jet triggers significant instability within the inner accretion region,likely the boundary layer and corona.This disruption explains the observed delays in the CCF and simultaneously quenches the conditions required for coherent oscillations,leaving only flat-topped noise in the PDS.We constrain the size of this unstable region in the inner region of accretion to be~10-40 km.In contrast,the symmetric CCFs and persistent oscillations(NBO/NBO+HBO)during URF events suggest a more stable,steady accretion flow.Although connecting the URF to a specific oscillation is difficult,its strong association with the NB phase of variation suggests a common underlying physical mechanism.Therefore,the CCF's asymmetry acts as a powerful diagnostic,linking ballistic jets to disk instability and URFs to a stable accretion state.Various physical scenarios are discussed to understand the connection among X-ray CCFs,PDS,and radio ejections in Sco X-1.展开更多
介绍了21世纪国际上第一个X射线天文学会议的简况1概况《X射线天文学的新世纪(NewCentury of X-ray Astronotny)》学术会议2001年3月6~8日在日本国横浜市举行,出席会议的代表共283人。其中日本代表156人,美国60人,德国24人,意大利9人,英...介绍了21世纪国际上第一个X射线天文学会议的简况1概况《X射线天文学的新世纪(NewCentury of X-ray Astronotny)》学术会议2001年3月6~8日在日本国横浜市举行,出席会议的代表共283人。其中日本代表156人,美国60人,德国24人,意大利9人,英国7人,荷兰、波兰和印度各4人,中国、法国和韩国各3人,乌克兰2人,澳大利亚、葡萄牙和喀麦隆各1人。出席会议人数之多是出乎人们意料的,会议共提出特邀报告12篇、一般口头报告40篇和墙报206篇.报告展示了X射线天文学的最新成果,今后的计划和展望。展开更多
基金supported by the National Natural Science Foundation of China(No.12035020)National Key Scientific Instrument and Equipment Development Projects of China(No.42327802).
文摘The main scientific payload of Macao Science Satellite-1B is a solar soft X-ray detection unit.To obtain an accurate solar X-ray spectrum,we have designed low-noise,high-throughput electronics.Solar radiation is detected using a low-leakage silicon drift detector(SDD),which is cooled to-30℃.The SDD output is processed using two parallel shaping amplifiers with peaking times of 315 ns and 65 ns.The amplifiers are designed using two-pole multiple-feedback active low-pass filters optimized to achieve a Bessel response.The differential output of the shaping amplifier generates a bipolar signal.The phase of the differential stage is tuned to ensure zero crossing corresponding to the peak of the shaping amplifier.A high-speed switch is inserted between the shaping amplifier and the peak-hold capacitor,and the peak value is maintained by turning off the switch.Fast and slow peak-hold circuits share a common ADC via time-division multiplexing.Both peak values are sampled for space-background rejection.Traditional pile-up detection methods cannot distinguish pulses that overlap in a fast channel.In this study,the differential of the“fast shaping”is selected,enabling the distinction of events separated by as little as 65ns,which is crucial for solar flare detection.The energy resolution is measured to be 138 eV at 5.90 keV.The centroid drift is less than 3.6 eV between-5℃ and 20℃.Compared with other solar X-ray instruments,this study demonstrates improved energy resolution with a lower peaking time,indicating a higher solar flare detection capability.
基金the support of the DST-ANRF(Anusandhan National Research Foundation)Core Research Grant project,Government of India。
文摘Based on the RXTE observations of Sco X-1,we identified a clear dichotomy in the behavior of its X-ray crosscorrelation functions(CCFs)which is possibly associated with two different radio jet ejection events.Twenty six observations display asymmetric CCFs of low correlation coefficients with soft or hard delays of a few hundred seconds along with no oscillation feature in the power density spectrum associated with horizontal branch/hard apex.All the observations belonging to NB/FB have symmetric CCFs with NBO/NBO+HBO/FBO in the PDS.Based on radio observations,two different types of jets were associated with Sco X-1 i.e.,ballistic radio jets and an ultra-relativistic flow(URF).We noted that asymmetric CCFs with delays were connected with ballistic or lobe radio jets and symmetric CCFs with URFs in Sco X-1.We interpret these findings as evidence of two different states of the inner accretion disk.We propose that the launch of a ballistic jet triggers significant instability within the inner accretion region,likely the boundary layer and corona.This disruption explains the observed delays in the CCF and simultaneously quenches the conditions required for coherent oscillations,leaving only flat-topped noise in the PDS.We constrain the size of this unstable region in the inner region of accretion to be~10-40 km.In contrast,the symmetric CCFs and persistent oscillations(NBO/NBO+HBO)during URF events suggest a more stable,steady accretion flow.Although connecting the URF to a specific oscillation is difficult,its strong association with the NB phase of variation suggests a common underlying physical mechanism.Therefore,the CCF's asymmetry acts as a powerful diagnostic,linking ballistic jets to disk instability and URFs to a stable accretion state.Various physical scenarios are discussed to understand the connection among X-ray CCFs,PDS,and radio ejections in Sco X-1.
文摘介绍了21世纪国际上第一个X射线天文学会议的简况1概况《X射线天文学的新世纪(NewCentury of X-ray Astronotny)》学术会议2001年3月6~8日在日本国横浜市举行,出席会议的代表共283人。其中日本代表156人,美国60人,德国24人,意大利9人,英国7人,荷兰、波兰和印度各4人,中国、法国和韩国各3人,乌克兰2人,澳大利亚、葡萄牙和喀麦隆各1人。出席会议人数之多是出乎人们意料的,会议共提出特邀报告12篇、一般口头报告40篇和墙报206篇.报告展示了X射线天文学的最新成果,今后的计划和展望。
