反电子中微子的反β衰变反应链实验的触发系统实现
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摘要
中微子的实验研究对理解宇宙的演化和揭示可能出现的新物理具有非常重要的意义,是当前的一个研究热点。
论文从不同类型中微子物理实验研究的目的和要求出发,分析了在中微子探测中所采用的反电子中微子反β衰变反应链模式的特性。有针对性地设计了相关的电子学触发系统,实现了对中微子信号的探测。
针对日本超级神冈中微子实验在探测超新星遗迹中微子过程中所出现的本底与信号特性,首次提出了正电子关联的强制触发机制。在该实验已有的触发系统基础上添加了强制触发模块,使探测器在纯水环境中具有识别反电子中微子的反β衰变反应链的能力。该方法成功降低了非关联的宇宙线本底,提高了统计显著性,实现无触发阈状态下探测中微子事例,触发模块自身的触发效率接近100%。并在水质切伦科夫探测器中首次观察到中子衰变曲线,测量出相应的中子寿命为(201±13)μs。
而在要求高精度的大亚湾反应堆中微子振荡实验中,为整个实验设计了完整的触发系统。通过多种独立触发机制的互相校验,保证触发的高效率和可测量;用高速可编程电子学技术提高了触发系统的灵活性,能适用于不同的子探测器;设计了子探测器间的交叉触发增强对本底事例的研究手段;独立高精度的时钟系统提供了分布式实验站的基准时间,在不增加相关子探测器相关度的前提下建立物理事例的时间关联。
The experimental research of neutrinos plays an important role in understanding the evolution of the universe, and is a most possible way to discover the possible new physics.
Based on the physics goals and the requirements of different neutrino experiments, this paper analyzed the features of the inverse beta decay reaction chain of anti-electron-neutrino used in the neutrino detection. Relevent electronic trigger systems have been designed, realizing the detection of neutrino signals.
The Super-Kamiokande Neutrino experiment is suffering from a cosmis muon neutrino background in detecting supernova relic neutrino. To solve this problem, the paper has developed a new forced trigger technique to provide a coincident detection on both the prompt positron signal and the delayed neutron from the inversed decay. This technique includes a hardware trigger module and a software trigger algorithm, which are both compatible with SK’s present system. This technique has also greatly suppressed the cosmic ray background and increased the significance of signal; the neutrino capture time curve in pure water was observed in the first time and the corresponding lifetime was also measured to be (201±13)μs.
The Daya Bay reactor neutrino oscillation experiment requires a very high precision to measure the mixing angleθ13 downto 1%. To meet this requirement, a great efford has been made to design the the whole trigger system: the multi indepentdent trigger algorithms are implemented to cross check each other to ensure a high trigger efficiency; the use of high speed programmable logic can increase the flexibility of trigger system; the mechanism of cross-trigger among different sub-detectors enables the ability in the background study; the independent high-accurate clock system can provide a uniform time reference for the distributed experiment halls, giving a time-relation among events from different halls without increasing the detector correlation.
论文从不同类型中微子物理实验研究的目的和要求出发,分析了在中微子探测中所采用的反电子中微子反β衰变反应链模式的特性。有针对性地设计了相关的电子学触发系统,实现了对中微子信号的探测。
针对日本超级神冈中微子实验在探测超新星遗迹中微子过程中所出现的本底与信号特性,首次提出了正电子关联的强制触发机制。在该实验已有的触发系统基础上添加了强制触发模块,使探测器在纯水环境中具有识别反电子中微子的反β衰变反应链的能力。该方法成功降低了非关联的宇宙线本底,提高了统计显著性,实现无触发阈状态下探测中微子事例,触发模块自身的触发效率接近100%。并在水质切伦科夫探测器中首次观察到中子衰变曲线,测量出相应的中子寿命为(201±13)μs。
而在要求高精度的大亚湾反应堆中微子振荡实验中,为整个实验设计了完整的触发系统。通过多种独立触发机制的互相校验,保证触发的高效率和可测量;用高速可编程电子学技术提高了触发系统的灵活性,能适用于不同的子探测器;设计了子探测器间的交叉触发增强对本底事例的研究手段;独立高精度的时钟系统提供了分布式实验站的基准时间,在不增加相关子探测器相关度的前提下建立物理事例的时间关联。
The experimental research of neutrinos plays an important role in understanding the evolution of the universe, and is a most possible way to discover the possible new physics.
Based on the physics goals and the requirements of different neutrino experiments, this paper analyzed the features of the inverse beta decay reaction chain of anti-electron-neutrino used in the neutrino detection. Relevent electronic trigger systems have been designed, realizing the detection of neutrino signals.
The Super-Kamiokande Neutrino experiment is suffering from a cosmis muon neutrino background in detecting supernova relic neutrino. To solve this problem, the paper has developed a new forced trigger technique to provide a coincident detection on both the prompt positron signal and the delayed neutron from the inversed decay. This technique includes a hardware trigger module and a software trigger algorithm, which are both compatible with SK’s present system. This technique has also greatly suppressed the cosmic ray background and increased the significance of signal; the neutrino capture time curve in pure water was observed in the first time and the corresponding lifetime was also measured to be (201±13)μs.
The Daya Bay reactor neutrino oscillation experiment requires a very high precision to measure the mixing angleθ13 downto 1%. To meet this requirement, a great efford has been made to design the the whole trigger system: the multi indepentdent trigger algorithms are implemented to cross check each other to ensure a high trigger efficiency; the use of high speed programmable logic can increase the flexibility of trigger system; the mechanism of cross-trigger among different sub-detectors enables the ability in the background study; the independent high-accurate clock system can provide a uniform time reference for the distributed experiment halls, giving a time-relation among events from different halls without increasing the detector correlation.
引文
[1]何景棠,中微子质量和中微子振荡实验物理学进展Jun,2001
[2] K.S.Hirata et al., The Kamiokande Collaboration, Phys. Rev. Lett. 58, 1490 (1987)
[3] R.M.Bionta et al., The IMB Collaboration, Phys. Rev. Lett. 58, 1494 (1987)
[4] Y.Fukuda et al., Evidence for Oscillation of Atmospheric Neutrinos at Phys. Rev. Lett. 81, 1562 (1998)
[5] M.Shiozawa et al., Search for Proton Decay via p→e+π0 in a Large Water Cherenkov Detector at Phys. Rev. Lett. 81, 3319 (1998)
[6] Y.Suzuki, Spin-orbit splitting ofΛ9Be excited states studied with the SU6 quark-model baryon-baryon interactions at Nucl. Phys. B P.S. 137, 5 (2004)
[7] T.Totani et al., Neutrino Burst from Supernovae and the Implications for Neutrino Oscillation Parameters at Astropart. Phys. 3, 367 (1995)
[8] T.Totani et al., Supernova relic neutrino background at Astrophys. J. 460, 303 (1996)
[9] R.A.Malaney, Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector at Astropart. Phys. 7, 125 (1997)
[10] D.H.Hartmann et al., Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector at Astropart. Phys. 7, 137 (1997)
[11] M.Kaplinghat et al., Supernova relic neutrino background atPhys. Rev. D 62, 043001 (2000)
[12] S.Ando et al., Detection potential for the diffuse supernova neutrino background in the large liquid-scintillator detector LENA at Astropart. Phys. 18, 397 (2003)
[13] M.S.Malek, Ph.D Dissertation (2003)
[14] M.S.Malek et al., Three-generation flavor transitions and decays of supernova relic neutrinos at Phys. Rev. Let. 90, 061101 (2003)
[15] J.F.Beacom et al., Antineutrino Spectroscopy with Large Water ?erenkov Detectors at Phys. Rev. Lett 93 171101 (2004)
[16] S.Chen et al., Production and Decay of at BABAR at Nucl. Phys. B-P.S. 166 252 (2007)
[17] Zhu Yong-Sheng, High Energy Phys. Nucl. Phys. 30(4) 331 (2006)
[18] http://root.cern.ch
[19] M.Nakahata et al., Limits On the Neutrino Magnetic Moment Using 1496 Days of Super-Kamiokande-I Solar Neutrino Data at Nucl. Instrum. Meth. A 421 113 (1999)
[20] Y.Koshio, Ph.D Dissertation (1998)
[21] http://root.cern.ch/root/html/examples/mlpHiggs.C.html
[22] H.Zhang, SK Collaboration Meeting Report, 2006
[23] Fogli G L et al., Physical region for three-neutrino mixing angles at hep– ph/050637
[24]王贻芳大亚湾反应堆中微子实验物理2006年3期
[25] www.fnal.gov
[26]大亚湾合作组大亚湾中微子实验初步设计报告
[27]薛涛,龚光华,邓智,陈少敏,邵贝贝超级神冈中微子实验的强制触发模块设计核电子学与探测技术2008年3期
[28] www-sk.icrr.u-tokyo.ac.jp/sk/index-e.html
[29] http://sales.hamamatsu.com
[2] K.S.Hirata et al., The Kamiokande Collaboration, Phys. Rev. Lett. 58, 1490 (1987)
[3] R.M.Bionta et al., The IMB Collaboration, Phys. Rev. Lett. 58, 1494 (1987)
[4] Y.Fukuda et al., Evidence for Oscillation of Atmospheric Neutrinos at Phys. Rev. Lett. 81, 1562 (1998)
[5] M.Shiozawa et al., Search for Proton Decay via p→e+π0 in a Large Water Cherenkov Detector at Phys. Rev. Lett. 81, 3319 (1998)
[6] Y.Suzuki, Spin-orbit splitting ofΛ9Be excited states studied with the SU6 quark-model baryon-baryon interactions at Nucl. Phys. B P.S. 137, 5 (2004)
[7] T.Totani et al., Neutrino Burst from Supernovae and the Implications for Neutrino Oscillation Parameters at Astropart. Phys. 3, 367 (1995)
[8] T.Totani et al., Supernova relic neutrino background at Astrophys. J. 460, 303 (1996)
[9] R.A.Malaney, Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector at Astropart. Phys. 7, 125 (1997)
[10] D.H.Hartmann et al., Direct measurement of supernova neutrino emission parameters with a gadolinium-enhanced Super-Kamiokande detector at Astropart. Phys. 7, 137 (1997)
[11] M.Kaplinghat et al., Supernova relic neutrino background atPhys. Rev. D 62, 043001 (2000)
[12] S.Ando et al., Detection potential for the diffuse supernova neutrino background in the large liquid-scintillator detector LENA at Astropart. Phys. 18, 397 (2003)
[13] M.S.Malek, Ph.D Dissertation (2003)
[14] M.S.Malek et al., Three-generation flavor transitions and decays of supernova relic neutrinos at Phys. Rev. Let. 90, 061101 (2003)
[15] J.F.Beacom et al., Antineutrino Spectroscopy with Large Water ?erenkov Detectors at Phys. Rev. Lett 93 171101 (2004)
[16] S.Chen et al., Production and Decay of at BABAR at Nucl. Phys. B-P.S. 166 252 (2007)
[17] Zhu Yong-Sheng, High Energy Phys. Nucl. Phys. 30(4) 331 (2006)
[18] http://root.cern.ch
[19] M.Nakahata et al., Limits On the Neutrino Magnetic Moment Using 1496 Days of Super-Kamiokande-I Solar Neutrino Data at Nucl. Instrum. Meth. A 421 113 (1999)
[20] Y.Koshio, Ph.D Dissertation (1998)
[21] http://root.cern.ch/root/html/examples/mlpHiggs.C.html
[22] H.Zhang, SK Collaboration Meeting Report, 2006
[23] Fogli G L et al., Physical region for three-neutrino mixing angles at hep– ph/050637
[24]王贻芳大亚湾反应堆中微子实验物理2006年3期
[25] www.fnal.gov
[26]大亚湾合作组大亚湾中微子实验初步设计报告
[27]薛涛,龚光华,邓智,陈少敏,邵贝贝超级神冈中微子实验的强制触发模块设计核电子学与探测技术2008年3期
[28] www-sk.icrr.u-tokyo.ac.jp/sk/index-e.html
[29] http://sales.hamamatsu.com
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