Meson Science Research with Intense Muon Beam

利用强介子束进行介子科学研究

基本信息

批准号：
01044036
负责人：
YAMAZAKI Toshimitsu
金额：
$ 18.24万
依托单位：
The Univetsity of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

In 1988 a new slow and D. C. negative muon channel was completed by the cooperative work between UTMSL (The University of Tokyo, Meson Science Laboratory) and TRIUMF (Tri-University Meson Facility, Vanconver, Canada) with the help of the Grant-in-Aid for special Project Research on Meson Science from Mombusho. Now, this channel located in the meson area of TRIUMF gives an opportunity for Japanese and international researchers to use the world strongest negative muon beam.With support of the present "KOKUSAI-GAKUJTYUTSU-KENKYU", many important muon experiments have been carried out by using this new negative muon channel.The importance of the oxygen in the high Tc superconducting materials have been emphasized by many theoreticians and also by many experimentalists, for which there exist a few proper probes. The negative muon captured at the oxygen nucleus is one of the most efficient microscopic probe which can detect the local electric and magnetic fields at the oxygen site.The joint … More group of UTMSL-RIKEN-Yamanashi University has found two different negative muon signals corresponding to different oxygen sites, using the very pure single srystal of LaSrCuO. The paramagnetic shift and the relaxation rate are studied for the various concentrations of the doped impurities. There temperature dependence as well as crystal axes dependences are obtained. The parts of this experiment have been reported at the 5th International Conference of muSR (Oxford, 1990) and International Conference on High Tc (Kanazawa, 1991).Also to the other group of high Tc materials YBzCuO, negative muon study was applied. There, rather small amplitude of mu^-SR signal was found for the sample which shows superconductivity but a fairly large signal was obtained for the sample which shows antiferromagnetic ordering. In order to obtain the general understanding of the negative muon behavior in the magnetic oxides a systematic study are carried out on the various 3d-metal oxides.On the other hands, the positive muon has been established as a unique and proper microscopic probes to detect antiferromagnetic ordering or weak magnetic local field, which is very difficult to be observed with another method. With this reason mu^+SR has intensively been applied on studiesof high Tc superconductors. The study was extended to new high Tc superconducting materials Bi_2Sr_2YCuO_y, Bi_2(Sr_<1-x>, La_x)_2Cuo_y, YBa(Cu_<1-x>, Cu_x)O, PrCuO, GdCeCuO etc. Another achievement is the success of mu^+SR measurement for the the high Tc material located inside the thick walled chamber for high pressure studies up to 0.6Gp.The study of Peierls instability transition has been performed for one dimensional polymers polyacetylene, using a negative muon captured at carbon forming a substitutional boron-like impurity.The interaction of slow muon and the thin foils was studied by detecting the distribution of secondary electron numbers. From the average number distribution of emitted electrons, charge asymmetric effect was obtained. The charge symmetric effect [n(mu^+)-n(mu^-)]/[n(mu^+)+n(mu^-)] called the Barkas effect (asymmetric effect in stopping power) was obtained for the momentum region 5 Mev/c - 12 Mev/c.New exploratory experiments on meson production have been carried out at TRIUMF, CERN, GSI and Saclay. The most exciting result is also the observation of delayed antiproton annihilation in helium medium. Less

1988年，在UTMSL（东京大学，梅森科学实验室）和Triumf（加拿大Vanconver，Vanconver，Triumf）之间的合作工作完成了新的慢速和D. C. C.负MUON频道。现在，这个位于Triumf梅森地区的频道为日本和国际研究人员提供了一个机会，可以利用世界强烈的负频束。在当前的“ Kokusai-gakujtyutsu-kenkyu”的支持下，许多重要的Muon实验都通过使用这种新的负uon来实现了许多重要的Muon Channel。实验者，存在一些适当的问题。在氧气核us上捕获的负元素是最有效的显微镜探针之一，可以检测氧气位置的局部电和磁场。关节……更多的UTMSL-RIKEN-YAMANASHI大学，使用非常纯净的单晶Lasrcuo的纯氧气位点，发现了两个不同的负脉络信号，与不同的氧气位点相对应。研究了掺杂的杂质的各种浓度的顺磁性移位和弛豫率。获得温度依赖性以及晶体轴的依赖性。该实验的一部分已在MUSR的第五次国际会议（牛津，1990年）和国际高TC会议（Kanazawa，1991年）。也向其他高的TC材料YBZCUO YBZCUO进行了负面的MUON研究，对MU^-SR信号进行了较大的示例，该示例是一个公平的示例。抗铁磁有序。为了获得对磁性氧化物的负un行为的一般理解，在各种3D金属氧化物上进行了系统的研究。在另一只手中，已经建立了正元作为一种独特且适当的显微镜探针，以检测抗毒素磁序或弱磁场，这是非常困难的，这是一种很难与另一种方法相似的。由于这个原因，Mu^+SR已大量应用于高TC超导体的研究。 The study was extended to new high Tc superconductors Bi_2Sr_2YCuO_y, Bi_2(Sr_<1-x>, La_x)_2Cuo_y, YBa(Cu_<1-x>, Cu_x)O, PrCuO, GdCeCuO etc. Another achievement is the success of mu^+SR measurement for the high Tc material located inside the thick walled chamber for high压力研究高达0.6GP。 PEIERLS不稳定性转变的研究已经对一维聚合物聚合物进行聚合物聚合物，使用在碳中捕获的负un捕获，形成替代性硼样杂质。缓慢的muon和薄箔的相互作用是通过检测二级电子数的分布来研究的。从发射电子的平均数分布中，获得了电荷不对称效应。对于Momentum 5 Mev/c-12 MeV/C-12 MeV/C.NEW探索实验，获得了barkas效应（停止功率的不对称效应），称为Barkas效应（停止功率的不对称效应），获得了电荷对称效应[N（Mu^+）-n（Mu^ - ）]/[N（Mu^+）+N（Mu^+）+N（Mu^ - ）]。最令人兴奋的结果也是观察氦培养基中延迟的抗抗原歼灭。较少的