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SUMMARY:Gamma-Gamma Angular Correlation Measurements With GRIFFIN
DTSTART;VALUE=DATE-TIME:20150616T223000Z
DTEND;VALUE=DATE-TIME:20150616T224500Z
DTSTAMP;VALUE=DATE-TIME:20200120T171155Z
UID:indico-contribution-841283@indico.cern.ch
DESCRIPTION:Speakers: Andrew MacLean (University of Guelph)\nWhen a excite
d nuclear state emits successive $\\gamma$-rays in a $\\gamma-\\gamma$ cas
cade\, $X^{**} \\rightarrow X^{*} + \\gamma_{1} \\rightarrow X + \\gamma_{
2}$ an anisotropy is found in the spatial distribution of $\\gamma_{2}$ wi
th respect to $\\gamma_{1}$. By defining the direction of $\\gamma_{1}$ to
be the z-axis\, the intermediate level\, $X^{*} $\, in general will have
an uneven distribution of m-states. This causes an anisotropy in the angul
ar correlation of the second $\\gamma$-ray with respect to the first. The
correlations depend on the sequence of spin-parity values for the nuclear
states involved as well as the multipolarities and mixing ratios of the em
itted $\\gamma$-rays. These angular correlations are expressed by the $W(\
\theta)$ function:\n\\begin{center}\n\n$W(\\theta) = 1 + \\sum\\limits_{k
= even}^{2L} a_{k}P_{k}(cos\\theta)$\n\n\\end{center}\nwhere $L$ is the lo
west multipole order of the emitted $\\gamma$-rays and the $a_{k}$ are coe
fficients\\part{title} for all of the $P_{k}(cos\\theta)$ Legendre polynom
ials.\n\nAngular correlations can be used for the assignment of spins and
parities to nuclear states and thus provide a powerful means to elucidate
the structure of nuclei away from stability through $\\beta-\\gamma-\\gamm
a$ coincidence measurements. In order to explore the sensitivity of the ne
w 16 clover-detector GRIFFIN $\\gamma$-ray spectrometer at TRIUMF-ISAC to
such $\\gamma-\\gamma$ angular correlations\, and to optimize its performa
nce for these measurements\, we have studied a well known $4^{+}\\rightarr
ow 2^{+}\\rightarrow 0^{+}$ $\\gamma-\\gamma$ cascade from $^{60}$Co decay
through both experimental measurements and Geant4 simulations. Results of
these investigations will be presented in this talk.\n\nhttps://indico.ce
rn.ch/event/355942/contributions/841283/
LOCATION:University of Alberta CCIS L1-140
URL:https://indico.cern.ch/event/355942/contributions/841283/
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