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\markright{\underline{REV\TeX~4: $^{174,175}$Pt -- GREAT version 0.0}}
\title{Lifetimes of yrast states in $^{174}$Pt and $^{175}$Pt}
%=================================================================
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\author{H.~Watkins}
\altaffiliation[Corresponding Author: ]{hw@ns.ph.liv.ac.uk}
\affiliation{Department of Physics, Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom}
\author{T.~Grahn}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{D.T.~Joss}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{D.~O'Donnell}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\affiliation{STFC Daresbury Laboratory, Daresbury, Warrington, WA4
4AD, United Kingdom.}
\author{R.~Carroll}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{A.~Dewald}
\affiliation{Institut fur Kernphysik, Universit\"{a}t zu K\"{o}ln,
Zulphicer Strasse 77, 50937 K\"{o}ln, Germany.}
\author{P.T.~Greenless}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{M.~Hackstein}
\affiliation{Institut fur Kernphysik, Universit\"{a}t zu K\"{o}ln,
Zulphicer Strasse 77, 50937 K\"{o}ln, Germany.}
\author{U.~Jakobsson}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{P.M.~Jones}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}

\author{R.~Julin}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{S.~Juutinen}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{S.~Ketelhut}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{T.~Kr\"{o}ll}
\affiliation{Physik-Department E12, 85748 Garching, TU M\"{u}nchen,
Germany.}
\author{R.~Kr\"{u}cken}
\affiliation{Physik-Department E12, 85748 Garching, TU M\"{u}nchen,
Germany.}
\author{M.~Labiche}
\affiliation{STFC Daresbury Laboratory, Daresbury, Warrington,
WA4 4AD, UK.}
\author{M.~Leino}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{N.~Lumley}
\affiliation{The School of Physics and Astronomy,
The University of Manchester, M13 9PL, UK.}
\author{P.~Maierbeck}
\affiliation{Physik-Department E12, 85748 Garching, TU M\"{u}nchen,
Germany.}
\author{M.~Nyman}
\affiliation{Department of Physics,
University of Jyv\"{a}skyl\"{a}, P.O. Box 35, FI-40014, Finland.}
\author{P.~Nieminen}
\affiliation{Department of Physics,
University of Jyv\"{a}skyl\"{a}, P.O. Box 35, FI-40014, Finland.}
\author{J.~Pakarinen}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{R.D.~Page}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{P.~Peura}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{T.~Pissalla}
\affiliation{Institut fur Kernphysik, Universit\"{a}t zu K\"{o}ln,
Zulphicer Strasse 77, 50937 K\"{o}ln, Germany.}
\author{P.~Rahkila}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{J.~Revill}
\affiliation{Oliver Lodge Laboratory,

University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{W.~Rothen}
\affiliation{Institut fur Kernphysik, Universit\"{a}t zu K\"{o}ln,
Zulphicer Strasse 77, 50937 K\"{o}ln, Germany.}
\author{P.~Ruotsalainen}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{S.~Rigby}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{J.~Saren}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{P.J.~Sapple}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{M.~Scheck}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{C.~Scholey}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{J.~Simpson}
\affiliation{STFC Daresbury Laboratory, Daresbury, Warrington, WA4
4AD, United Kingdom.}
\author{J.~Sorri}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
\author{J.~Thomson}
\affiliation{Oliver Lodge Laboratory,
University of Liverpool, Liverpool, L69 7ZE, United Kingdom.}
\author{J.~Uusitalo}
\affiliation{Department of Physics, University of Jyv\"{a}skyl\"{a},
P.O. Box 35, FI-40014, Finland.}
%=================================================================
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\date{\today}
\begin{abstract}
The excited states in $^{174,175}$Pt were populated using the
$^{92}$Mo($^{86}$Sr,2p2n)$^{174}$Pt and $^{92}$Mo($^{86}$Sr,2pn)$^{175}$Pt fusion-evaporation reaction. Lifetime of the 6$^{+}$ yrast state in $^{174}$Pt has been extracted from recoil-decay tagged $\gamma$-ray spectra by using the recoil distance Doppler-shift method. In addition, lifetimes of the
17/2$^{+}$ and 21/2$^{+}$ yrast states in $^{175}$Pt have been extracted from recoil-gated $\gamma$$\gamma$-coincidence spectra.
\end{abstract}
\maketitle
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\section{Introduction}
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The nuclear phenomena of shape coexistence occurs when collective bands based on competing nuclear shapes, one of large prolate deformation, the other weakly oblate or nearly spherical, interfere. Shape polarisation occurs when one or more valence nucleons occupy deformation-driving orbitals and polarise it towards a certain shape. These phenomena have been a source of investigation with respect to nuclei near the proton dripline and the
$\textit{Z}$=82 closed proton shell.
Moving away from $\textit{Z}$=82, with decreasing proton number, leads to a region where the nuclei could already be well deformed in the ground state resulting in a decrease in the difference in deformation between the competing minima and the height of the potential barrier between them.
Theoretical calculations of the shape coexistence observed in
$^{174-180}$Pt suggest that the prolate minimum is due to the excitation of two (or more) protons across the $\textit{Z}$=82 gap into
$\pi\textit{h}_{9/2}/\textit{f}_{7/2}$ deformation driving orbitals~\cite{Dracoulis}.
The irregular level spacing observed at low spin in the yrast band of $^{176}$Pt was interpreted~\cite{Cederwall} as a competition between triaxial and prolate shapes relating to the occupation of different proton orbitals in the zero-quasiparticle ground state band. This behaviour was found to be more pronounced in $^{174}$Pt. The prolate deformed band results from a pair of nonaligned quasiprotons scattering into deformation-driving
$\textit{h}_{9/2}/\textit{f}_{7/2}$ orbitals~\cite{Dracoulis}. This irregular behaviour at low spin was also observed in the assigned
$\nu\textit{i}_{13/2}$ signature partner bands of $^{175}$Pt~\cite{Cederwall}.
It was also noted that the $\textit{N}$=98 gap stays almost constant when the $^{175}$Pt nucleus undergoes the calculated shape changes, implying the neutron configuration is not affect by the deformation changes.
Therefore the low spin irregularity observed in $^{175}$Pt was explained to be analogous to the crossing of different zero-quasiproton structures as discussed for the even-A Pt nuclei~\cite{Cederwall}.
For the ground states of $^{174,176}$Pt total Routhian surface (TRS) calculations~\cite{Cederwall} predict weakly deformed, $\gamma$ soft minima, with the $\gamma$-softness being even more pronounced in $^{174}$Pt. For $^{175}$Pt TRS calculations also showed, for the favoured $\alpha$=+1/2 signature, a polarisation of the shape but not the extent of $\gamma$ softness observed in the even Pt nuclei.
Experimentally the degree of collectivity for the low-lying excited states in nuclei can be determined from measuring the lifetime of the level.
In doing so the absolute transition probabilities can be determined and provide a direct measure of the collectivity.
In the present study, Recoil Distance Doppler Shift (RDDS)~\cite{Schwarz} lifetime measurements have been carried out in $^{174}$Pt and for the first time an odd-A Pt nucleus $^{175}$Pt. The lifetimes of the low-lying yrast states in $^{175}$Pt and the 6$^{+}$ state in $^{174}$Pt have been measured.

For the 17/2$^{+}$ state in $^{175}$Pt the $\mid$Q$_{t}\mid$ value is in agreement with the non-collective, possible triaxial assignment whilst the 21/2$^{+}$ is part of the collective, prolate deformed band.
The 6$^{+}$ state in $^{174}$Pt is also a member of the collective, prolate band.
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\section{Experimental Details}
%=================================================================
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The experiment was performed at the Accelerator Laboratory of the
University of Jyv\"{a}skyl\"{a}, Finland. Excited states in
$^{174,175}$Pt were populated in heavy ion fusion-evaporation reactions using a 1 mg/cm$^{2}$ thick $^{92}$Mo target with a beam of $^{86}$Sr$^{16+}$ ions accelerated to an energy of 401 MeV using the
K130 cyclotron. The reaction resulted in initial recoil velocities of v/c = 4.4$\%$.
Prompt $\gamma$ rays were detected using the JUROGAM Ge-detector array consists of 39 Compton suppressed high-purity Ge detectors,
24 of which are segmented Clover detectors. The K\"{o}ln plunger device was installed at the JUROGAM target position to perform
Recoil Distance Doppler-Shift (RDDS) lifetime measurements. The average beam current was 2pnA, limited by heating of the stretched target and the counting rate of the JUROGAM array.The low production cross sections of $^{174,175}$Pt require high selectivity of prompt $\gamma$ rays. In order to separate the prompt $\gamma$-ray spectra of the recoil of interest from that of residues from other reaction channels and fission background, the standard stopper foil of the plunger device was replaced by a
1 mg/cm$^{2}$ Mg degrader foil. This allows evaporation residues to recoil into the gas-filled separator Recoil Ion Transport Unit
(RITU)~\cite{Leino}, which separates recoiling evaporation residues from the scattered beam from according to their magnetic rigidity. The recoils are transported to the focal plane of RITU to the GREAT spectrometer~\cite{Page} which is utilised for the recoil-gated tagging technique (RDT)~\cite{Paul}. At its entrance the GREAT spectrometer contains a MultiWire Proportional Counter (MWPC) to record the energy loss and provide timing information of the recoils.
After passing through the MWPC, the recoils were implanted into a pair of adjacent Double-sided Silicon Strip Detectors (DSSDs).
The DSSDs record the arrival time of the recoil as well as its subsequent radioactive decay properties.
The timing and energy loss information of the MWPC was combined with the timing information of the DSSDs to select recoil evaporation residues. Thus, the prompt $\gamma$ rays recorded at the target position by JUROGAM were associated with recoils detected at GREAT and recoil-gated $\gamma$-ray spectra were constructed. For recoils with favourable $\alpha$-decay properties of relatively short half-life and sufficient branching ratio, the characteristic $\alpha$ decay can be used to associate the prompt $\gamma$ rays unambiguously to the nucleus

under study. The $\alpha$ decays detected by the DSSDs were temporally and spatially correlated with the detected recoils and subsequently to the prompt $\gamma$ rays. Hence, RDT tagged $\gamma$-ray spectra were constructed. The data were collected using the
Total Data Readout triggerless data acquisition system~\cite{Lazarus}.
The spectra was constructed using the GRAIN software package~\cite{Rahkila}.
\subsection{A. $^{174}$Pt}
The $\alpha$ decays of $^{174}$Pt (E$_{\alpha}$=6040keV,t$_{1/2}$=889ms)
~\cite{Akovali} were correlated with the recoils and singles RDT $\gamma$ spectra were constructed. For the RDDS measurement on $^{174}$Pt only ring 1
(5 detectors at an angle of 158$^{0}$) and ring 2 (10 detectors at an angle of 134$^{0}$ with respect to the beam direction) of the JUROGAM
Ge detectors were used. The spectra were recorded with 10 different target-to-degrader distances ranging from 3 to 3000 $\mu$m. Examples of the singles $\gamma$-ray spectra are shown in Fig.~\ref{fig:tar2deg} . The fitted peak areas were normalised to the summed intensities of degraded (I$_{d}$) and fully shifted (I$_{s}$) components of transitions under investigation and decay curves of I$_{s}$/(I$_{d}$+I$+{s}$) were constructed. The lifetime of the I$^{\pi}$ = 6$^{+}$ yrast state was extracted using the
Differential Decay Curve Method (DDCM) ~\cite{Dewald}, illustrated in
Fig.~\ref{fig:174DecCur}.
The resulting mean lifetime $\tau$ values presented in ~\ref{tab:elecmag} are weighted averages of the two values extracted separately from the data recorded with the detectors at 134$^{\circ}$ and 158$^{\circ}$.
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.98\columnwidth]{tar_to_deg.eps}
\caption{\label{fig:tar2deg} Singles RDT $\gamma$-ray spectra of $^{174}$Pt measured at three target-to-degrader distances with ten JUROGAM detectors at
134$^{\circ}$ with respect to the beam axis. The dashed (dotted) lines indicate the positions of the fully Doppler-shifted (degraded) components of the transitions under study.}
\end{center}
\end{figure}
In the case of $^{174}$Pt, the statistics did not allow for $\gamma\gamma$ analysis. For the analysis of singles RDDS data the effect of unobserved feeding transitions must be taken into account.
If the majority of the feeding is observed and the lifetime of the observed transition is not long compared with that of the depopulating transition, it is realistic to assume that the time behaviour of the unobserved feeding is similar to that of the observed feeding.
This has been studied in several cases and verified by the coincidence analysis (see Ref~\cite{Grahn} and references therein).
This assumption is valid for the 6$^{+}$ in $^{174}$Pt.
\begin{figure}
\begin{center}[h!]
\includegraphics[width=0.90\columnwidth]{pt174_6+_black.eps}
\caption{\label{fig:174DecCur} Lifetime determination using singles

RDDS data of the JUROGAM ring 2 detectors for the 6$^{+}$ state in
$^{174}$Pt. The top panel shows the decay curve of the depopulating transition. The middle panel shows the difference between the degrading components of the feeding and depopulating transitons, the line is the derivative of the decay curve shown in the upper panel.
The lower panel shows the individual lifetimes at the target-to-degrader distances in the region of sensitivity and the final average lifetime. }
\end{center}
\end{figure}
\subsection{B. $^{175}$Pt}
In the case of $^{175}$Pt the statistics permitted a $\gamma\gamma$ analysis. For $\gamma\gamma$-coincidence analysis recoil-gated $\gamma$ rays recorded with the JUROGAM detectors at either 158$^{\circ}$ (5 detectors) or 134$^{\circ}$ (10 detectors) and with the whole JUROGAM array were sorted into two separate matrices for each of the 10 target-to-degrader distance. To exclude the uncertainties originating for the time behaviour of unobserved feeding, the projected spectra were gated with transitions directly feeding levels of interest and projected onto the axis recorded with the JUROGAM detectors at either 134$^{\circ}$ or
158$^{\circ}$.
In standard DDCM analysis gates are usually set on the fully Doppler-shifted component of the feeding transition. However, in the present work it was necessary to gate on the full line shape~\cite{Dew}, corresponding to the degraded and fully-shifted component of the detected $\gamma$-ray transition recorded with all the JUROGAM Ge detectors to increase statistics of the $\gamma\gamma$-coincidence spectra of $^{175}$Pt.
The normalised decay curves I$_{s}$/(I$_{d}$+I$+{s}$) were constructed and the results of the application of the DDCM to the intensity measurements for the 17/2$^{+}$ and 21/2$^{+}$ are shown in Fig.~\ref{fig:175DecCur_1} and Fig.~\ref{fig:175DecCur_2}, respectively. The mean lifetime $\tau$ values of the yrast states 17/2$^{+}$ and 21/2$^{+}$ presented in ~\ref{tab:elecmag} were extracted separately from the data recorded with the detectors at 158$^{\circ}$ and those at 134$^{\circ}$ using the DDCM. The resulting state lifetimes are weighted averages of these two values.
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.90\columnwidth]{175Pt_172+_black.eps}
\caption{\label{fig:175DecCur_1} Lifetime determination of the 17/2$^{+}$ state in $^{175}$Pt using $\gamma\gamma$-coincidence matrix data. Each panel represents that same as explained in ~\ref{fig:174DecCur}. The decay curve in the top panel is extracted from the coincidence spectra gated on the direct feeding transition of the state.}
\end{center}
\end{figure}
\begin{figure}[h!]
\begin{center}
\includegraphics[width=0.90\columnwidth]{175Pt_212+_black.eps}
\caption{\label{fig:175DecCur_2} Lifetime determination of the 21/2$^{+}$

state in $^{175}$Pt using the DDCM as described in ~\ref{fig:175DecDur_1}.}
\end{center}
\end{figure}
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\section{Results and Discussion}
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The lifetime of the two lowest yrast states in $^{175}$Pt and the 6$^{+}$ state in $^{174}$Pt were obtained and are presented in Table~\ref{tab:elecmag} along with the absolute values of transition quadrupole moments Q$_{t}$ and deformation parameters $\beta^{(t)}_{2}$, extracted from the experimental B(E2) values.
For $^{174}$Pt the 497 keV and 501 keV $\gamma$-rays (4$^{+}$ $\rightarrow$
2$^{+}$ and 8$^{+}$ $\rightarrow$ 6$^{+}$ transition respectively) could not be resolved (see Fig.~\ref{fig:tar2deg}) as a result the lifetime of the 2$^{+}$ and
4$^{+}$ states could not be extracted.
\begin{table}[h!]
\caption{\label{tab:elecmag} Electromagnetic properties of the low lying yrast states in
$^{174,175}$Pt}
\begin{tabular}{cccccc}
\hline \hline
& $E_{\gamma}$ & $I^{\pi}_i$ & ${\tau}[ps]$ & B(E2)[W.u.] & $|Q_{t}|[eb]$ \\
\hline
$^{174}$Pt & 474 & 6$^{+}$ & 3(1) & 197(98) & 6(1) \\
\\
$^{175}$Pt & 328 & 17/2$^{+}$ & 33(3) & 156(20) & 4.5(2) \\
& 437 & 21/2$^{+}$ & 2(1) & 666(267) & 8.8(22) \\
\hline \hline
\end{tabular}
\end{table}
In order to discuss the significance of the lifetimes measured the kinematic moment of inertia of the even $^{172,178}$Pt and the odd $^{175}$Pt are compared in Fig.~\ref{fig:kinMOI}. The onset of the irregularity in the yrast level scheme at low spin can be seen in $^{176}$Pt and is very apparent in $^{174}$Pt.
This irregularity has been interpreted as a crossing of a near-spherical ground state sequence by a more deformed vacuum configuration in the framework of a two band mixing model~\cite{Dracoulis}. From the kinematic moment of inertia it can be seen that the yrast band in $^{175}$Pt behaves in a similiar way to that of $^{174}$Pt as predict by TRS calculations performed by Cederwall et al~\cite{Cederwall}. It was also noted that the $\textit{N}$=98 gap stays almost constant when the $^{175}$Pt nucleus undergoes the shape change, implying the odd neutron is decoupled from the deformed
$^{174}$Pt nucleus.
\begin{figure}
\begin{center}
\includegraphics[angle=90,width=0.98\columnwidth]{kinMOI_yrast.eps}
\caption{\label{fig:kinMOI} Kinematic moment of inertia MOI$^{1}$ vs rotational frequency
$\hbar\omega$ for the yrast bands of the even nuclei $^{172,178}$Pt and the favoured i$_{13/2}$ $\alpha$=+1/2 signature band of the odd-A

$^{175}$Pt.}
\end{center}
\end{figure}
The transition quadrupole moment $\mid$Q$_{t}\mid$ values extracted from the measured lifetimes of the yrast states in these neutron deficient Pt nuclei are compared in Fig.~\ref{fig:SpinQuad}. For $^{176}$Pt the trend in $\mid$Q$_{t}\mid$ implies the shape coexistence phenomena discussed previously, as the slightly lower transition strength of the 2$^{+}$ $\rightarrow$ 0$^{+}$ transition reflects a lower collectivity than the 4$^{+}$ $\rightarrow$ 2$^{+}$ yrast transition and higher. The small difference in $\mid$Q$_{t}\mid$ values indicates the subtlety of the band crossing behaviour.
\begin{figure}[h!]
\begin{center}
\includegraphics[angle=90,width=0.98\columnwidth]{SQ.eps}
\caption{\label{fig:SpinQuad} Experimental $\mid$Q$_{t}\mid$ values for the even A
$^{174-178}$Pt and the odd A $^{175}$Pt nuclei. The data for $^{176,178}$Pt are taken from ref.~\cite{Drac}.}
\end{center}
\end{figure}
The extracted $\mid$Q$_{t}\mid$ of $^{175}$Pt for the 17/2$^{+}$ $\rightarrow$
13/2$^{+}$ transition is slightly lower than the corresponding value for the 2$^{+}$ $\rightarrow$ 0$^{+}$ transition in $^{176}$Pt. This difference could indicate the increase in triaxility of the ground state with decreasing neutron number as proposed. For $^{174}$Pt the extracted $\mid$Q$_{t}\mid$ value for the 6$^{+}$ $\rightarrow$ 4$^{+}$ transition is comparable to that for $^{176,178}$Pt. This result provides evidence that the yrast 6$^{+}$ state in $^{174}$Pt is a likely member of the collective prolate band associated with the scattering of quasiprotons across the Z=82 shell gap into the $\pi$h$_{9/2}$/f$_{7/2}$ orbitals. It is understood that the yrast band in $^{176,178}$Pt is a pure member of these orbitals.
The larger $\mid$Q$_{t}\mid$ value for the 21/2$^{+}$ $\rightarrow$ 17/2$^{+}$ in comparison to the corresponding value for the 4$^{+}$ $\rightarrow$
2$^{+}$ in the even $^{176,178}$Pt could contribute further to the shape coexistence interpretation of the irregularity at low spin. Level energy systematics of the odd and even mass Pt nuclei show a strong coupling of the odd mass isotopes in relation to their even mass neighbours, the level energies are almost degenerate below N=98 reflecting the decoupling of the odd neutron from the weakly decoupled core as suggest by Cederwall et al~\cite{Cederwall}. Unfortunately the lifetimes of the corresponding 2$^{+}$ and 4$^{+}$ states in $^{174}$Pt could not be measured, and the error of the measured lifetime of the
21/2$^{+}$ state of $^{175}$Pt is too high to contribute to experimental measurements regarding the shape changes at low spin occuring in these
Pt nuclei.
%=================================================================
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\section{Summary and Conclusion}

%=================================================================
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To summarise, the lifetimes of the low-lying yrast states in $^{175}$Pt and the 6$^{+}$ state in $^{174}$Pt have been measured by employing the
RDDS technique and tagging methods, allowing the collectivity of the bands to be established. For the 17/2$^{+}$ state in $^{175}$Pt the $\mid$Q$_{t}\mid$ value is in agreement with the non-collective, possible triaxial assignment whilst the 21/2$^{+}$ is part of the collective, prolate deformed band.
The 6$^{+}$ state in $^{174}$Pt is also a member of the collective, prolate band.
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\begin{acknowledgments}
Financial support for this work has been provided by the UK Science and
Technology Facilities Council (STFC).
\end{acknowledgments}
%=================================================================
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\end{document}
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