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，UTMSL Y和Triumf（加拿大Vanconver，Tri-University Meson设施）之间的合作工作在1988年进行了负面的合作工作。 E和国际研究人员使用世界最强的负uon束的梅森地区的介子区域。与当前的支持。许多理论家和许多实验学家都强调了超导式的，其中有一些适当的探针。使用拉斯氏菌的纯为纯的尖锐症状，在掺杂的杂质的各种货架上研究了纯净的氧气。（牛津，1990年）和国际高TC会议（Kanazawa，1991年）。为了获得对磁性氧化物中的负ume行为的一般理解，对样品进行了序列。建立为独特的显微镜象征性gnetic有序或弱磁性局部场，这是非常差异的方法，该方法已将MU ^+SR的方法强烈地应用于超导体上。超导材料，BI_2（sr_ <1-x>，la_x）_2cuo_y，yba（cu_ <1-x>，cu_x）o，prcuo，gdcecuo等。另一个成就是位于位于Mu^+SR TC材料的成功腔室F或高度促进研究最高为0.6GP。PEIERLS不稳定性转移的研究已经对一维聚合物聚合物聚乙烯进行了，使用在碳中捕获的负雄乙烯，形成替代硼样杂质。通过次级电子数的分布进行了研究。在Triumf的动量区域5 MEV/C -12 MEV/C.新的介绍性经验是在Triumf中进行的。他最令人兴奋的结果也是对氦培养基中延迟的抗抗原灭绝的观察