BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Negative muon spin relaxation in water and ice
DTSTART;VALUE=DATE-TIME:20220828T100000Z
DTEND;VALUE=DATE-TIME:20220828T101500Z
DTSTAMP;VALUE=DATE-TIME:20220826T104756Z
UID:indico-contribution-3670@indico.stfc.ac.uk
DESCRIPTION:Speakers: Yoko Kimura (Dept. Phys. Osaka Univ.)\nMuons are the
  main component of cosmic ray particles on the earth\, and most of the cos
 mic ray muons are injected into water or ice\, which occupy more than 70% 
 of the earth's surface. When negative muons ($\\mu$$^-$) stop in H$_2$O\, 
 they are mainly trapped by oxygen nuclei and form muonic oxygen atoms O$\\
 mu$$^-$\, and about 15% of O$\\mu$$^-$ atoms finally change to stable nitr
 ogen isotopes $^{14}$N or $^{15}$N via the neutron emission after the muon
  capture process. The nitrogen isotopes produced by such a process may be 
 chemically active due to their high recoil energy and may form various nit
 rogen compounds through reactions with water molecules. In this situation\
 , $\\mu^-$SR spectroscopy is suitable for studying the behavior of such ac
 tive nitrogen in H$_2$O\, since O$\\mu^-$ atoms also act chemically as nit
 rogen. In the present study\, we measured $\\mu^-$SR spectra in water and 
 ice to approach what kind of nitrogen compounds are formed by cosmic-ray n
 egative muons\, and how they affect the surrounding chemical environment.\
 n Experiments were carried out at the D1 beamline in the Materials and Lif
 e Science Experimental Facility (MLF) of J-PARC. H$_2$O and D$_2$O samples
  were irradiated with a negative muon beam (47 MeV/c\, double pulse)\, and
  ZF and LF-$\\mu$$^-$SR spectra were measured. The result shows that the r
 elaxation due to the nuclear dipolar field is observed in solid H$_2$O and
  D$_2$O at 200 K. The field distribution widths were deduced to be $\\Delt
 a_H$=0.27 $\\mu$$s^{-1}$ and $\\Delta_D$=0.066 $\\mu$$s^{-1}$\, for H$_2$O
  and D$_2$O respectively. The relationship between these two values is wel
 l explained by the difference in the spins and magnetic moments of proton 
 and deuteron.\n In this conference\, we will discuss possible chemical sta
 tes based on the present results.\n\nhttps://indico.stfc.ac.uk/event/53/co
 ntributions/3670/
LOCATION: Aula dei Cavalieri\, University Central Palace\, via Università
  12
URL:https://indico.stfc.ac.uk/event/53/contributions/3670/
END:VEVENT
END:VCALENDAR