Design of compact neutron spin flipper based on cold neutron spectrum
-
摘要: 为节省极化中子散射谱仪传输光路的空间，实现特定冷中子谱的极化中子高效率自旋翻转，使用在空间上自然衰减的前端多层膜极化器静磁场作为中子自旋倒相器的导向磁场，在空间上形成了紧凑型冷中子自旋倒相器设计模型。介绍了实际模型物理参数的计算方法。对前端极化器静磁场在空间上的自然衰减进行了实验测试，根据测试结果及拟使用冷中子波段，针对设计的紧凑型中子自旋倒相器的相关参数进行了优化计算。模拟了极化中子在实际复合磁场中的自旋翻转图像，计算了自旋倒相器的翻转效率。对设计的紧凑型中子自旋倒相器进行了翻转效率物理实验测试，测试结果表明：设计的中子自旋倒相器翻转效率可在99.2%以上，达到了预期设计指标，可用于极化冷中子散射谱仪。Abstract: In order to save the limited space of polarized neutron scattering spectrometer and realize the high efficiency spin flip for the given energy band cold neutrons. A compact neutron flipper is established using the spontaneous attenuation magnetic field of polarizer as gradient magnetic field. The real calculation method is introduced, and spontaneous attenuation data of gradient magnetic field along the neutron beam flight is measured. Based on the real neutron wave band and workable dimension, the key parameters and flip probability for neutron flipper are calculated, and the distribution of neutron spin projection on the real magnetic field along the spin flipper is simulated. Finally, the measurement is done and the correction of the designed neutron flipper is discussed as well. Experimental results indicate that the flip probability can reach over 99.2%. The designed neutron spin flipper can satisfy the anticipant requirements, which can be used for construction of polarized neutron scattering instruments.
-
Key words:
- cold neutrons spectrum /
- spin flip /
- compact design /
- flip probability /
- spin flipper
-
[1] 丁大钊,叶春堂,赵志祥.中子物理学[M]. 北京:原子能出版社,2001. DING D ZH,YE CH T,ZHAO ZH X. Neutron Physics[M]. Beijing:Atom Energy Press,2001.(in Chinese).
[2] 冯蕴深.磁共振原理[M]. 北京:高等教育出版社,1992. FENG Y SH. Magnetic Resonance Principle[M]. Beijing:Higher Education Press,1992.(in Chinese)
[3] NEWTON R R,KITTEL C. On a proposal for determining the thickness of the transition layer between ferromagnetic domains by a neutron polarization experiment[J]. Physical Review,1948,74:1604-1605.
[4] ROBISCOE R T. A spin flip problem[J]. America J. Physics,1971,39:146-150.
[5] GRIGORIEV S V,OKOROKOV A I,RUNOV V V. Peculiarities of the construction and application of a broadband adiabatic flipper of cold neutrons[J]. Nucl. Instr. and Meth A,1997,384:451-456.
[6] SUMBATYAN A A,SLYUSAR V N,OKOROKOV A I,et al.. Methods and devices for reversing neutron polarization[J]. Nuclear Experimental Technique,2009,3:30-34.
[7] LEBEDEV V T,TöRÖK G. Broadband neutron spin-flippers on magnetized foils[J]. Nuclear Instruments and Methods in Physics Research A,2002,195:449-454.
[8] REKVELDT M TH,KELLER T,KRAAN W H. New instrumentation using Larmor precession of polarized neutrons[J]. Physica B,2001,297:18-22.
[9] HOLLEY A T,BROUSSARD L J,DAVIS J L,et al.. A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment[J]. Review Scientific Instruments,2012,83:0735051-07350517.
[10] TAKEDA T,YAMADA N L,SETO H,et al.. Development of spin flippers with steady current for the TOF-NSE spectrometer[J]. Physica B,2003,335:211-214.
[11] KRAAN W H,GRIGORIEV S V,REKVELDT M TH,et al.. Test of adiabatic spin flippers for application at pulsed neutron sources[J]. Nuclear Instruments and Methods in Physics Research A,2003,510:334-345.
[12] SLYUSAR V N,SOLOVEI V A,SUMBATYAN A A. A triangular-shaped current used in devices for reversing neutron polarization[J]. Instruments and Experimental Techniques,2009,4:50-53.
[13] KITAGUCHIA M,HINOA M,KAWABATAA Y,et al.. Development of neutron resonance spin flipper for high resolution[J]. Physica B,2006,385 386:1128-1130.
[14] KRAAN W H,REKVELDT M T. Single domain wall in FeNi film on Si as a neutron spin flipper[J]. Nuclear Instruments and Methods in Physics Research A,2008,596:422-429.
[15] OHOYAMA K,TSUTSUMI K,INO T,et al.. Development of a non-adiabatic two-coil spin flipper for a polarized thermal neutron diffractometer with a 3He spin filter[J]. Nuclear Instruments and Methods in Physics Research A,2012,680:75-81.
[16] PYNN R. Broadband spin flippers constructed from thin magnetic films[J]. Physica B,2005,356:178-181.
[17] WEINFURTER H,BADUREK G,RAUCH H,et al.. Inelastic action of a gradient radio-frequency neutron spin flipper[J]. Z.Phys. B,1988,72:195-201.
[18] FRANK A I,ANDERSON I,BONDAREKO I V,et al.. Larmor spin precession and neutron optics[J]. Physics of Atomic Nuclei,2002,65(11):2066-2078.
[19] 陈良,彭梅,孙良卫,等. 使用山嵛酸银标定中子小角散射谱仪关键参数[J]. 光学精密工程,2013,21(7):1755-1762. CHEN L,PENG M,SUN L W,et al.. Calibration of key parameters for small angle neutron scattering spectrometer by using silver behenate[J]. Opt. Precision Eng.,2013,21(7):1755-1762.(in Chinese)
[20] 王晓影,李建,谢超美,等. 中子衍射应力谱仪垂直聚焦单色器的优化设计[J]. 光学精密工程,2008,16(10):1880-1885. WANG X Y,LI J,XIE CH M,et al.. Optimal simulation of vertical monochromator of neutron diffraction residual stress instrument[J]. Opt. Precision Eng.,2008,16(10):1880-1885.(in Chinese)
[21] 李新喜,王燕,黄朝强,等. 斩盘产生的中子脉冲特性[J]. 光学精密工程,2009,17(9):2112-2119. LI X X,WANG Y,HUANG CH Q,et al.. Neutron pulse speciality produced by chop disk[J]. Opt. Precision Eng.,2009,17(9): 2112-2119.(in Chinese)
[22] 李新喜,王燕,黄朝强,等. 中子反射谱仪的闸门与会聚导管组合设计[J]. 光学精密工程,2009,17(12):2983-2989. LI X X,WANG Y,HUANG CH Q,et al.. Optimized combination of shutters and focus neutron guides for neutron reflectometers peciality produced by chop disk[J]. Opt. Precision Eng.,2009,17(9): 2112-2119.(in Chinese)
[23] 赵凯华,陈熙谋.电磁学[M]. 北京:高等教育出版社,2002. ZHAO K H,CHEN X M. Electromagnetics[M]. Beijing:Higher Education Press,2002.(in Chinese) -
点击查看大图
计量
- 文章访问数: 2049
- HTML全文浏览量: 613
- PDF下载量: 437
- 被引次数: 0
下载:
