Download The 3 MeV pygmy resonance in 163164 Dy

The 3 MeV pygmy resonance in
163,164Dy
Hilde-Therese Nyhus
Department of Physics University of Oslo
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Introduction
Motivation for analyzing these nuclei
Experimental method
Level density
Gamma-ray strength function
Motivation
Motivation
Various other rare earth nuclei
have been studied using the
Oslo method, one has then
measured a width of the pygmy
resonance between
1.2-1.5 MeV.
This contradicts what has been
measured in Prague for other
rare earth nuclei, where about
half the width has been found.
The reactions used to produce the nuclei
The reactions used to produce the nuclei
 At Oslo Cyclotron Laboratory:
164Dy(3He, 3He*)164Dy
164Dy(3He,
)163Dy
The reactions used to produce the nuclei
 At Oslo Cyclotron Laboratory:
164Dy(3He, 3He*)164Dy
164Dy(3He,
)163Dy
In Prague:
162Dy(n,
)163Dy
Experimental method
-Gate on the various particles to construct
coincidence matrix.
Coincidence matrixes
163Dy
164Dy
Experimental method
-Gate on the various particles to construct
coincidence matrix.
-Unfold the gamma spectrum and generate first
generation matrix.
First generation matrixes
163Dy
164Dy
Experimental method
-Gate on the various particles to construct
coincidence matrix.
-Unfold the gamma spectrum and generate first
generation matrix.
-The experimentally obtained first
generation
matrix is according to the Brink-Axel
hypothesis proportional to the level density
and gamma ray strength function.
P(E x ,E )T(E )(E x ,E )
Preliminary
Level density in 163,164Dy
163Dy
164Dy
Preliminary
Gamma-ray strength function with pygmy resonance
163Dy
164Dy
Gamma-ray
strength
function in
163Dy, with a
pygmy
resonance.
The width
of the
pygmy
resconance
masured in
Prague is
0.6 MeV
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Gamma-ray
strength
function in
164Dy, with a
pygmy
resonance.
Preliminary
Gamma-ray strength function with pygmy resonance
163Dy
Gamma-ray
strength
function in
163Dy, with a
pygmy
resonance.
The width
of the
pygmy
resconance
masured in
Prague is
0.6 MeV