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The $ \beta^{{+}}_{}$ /EC decay of 189m, gPb has been studied at the ISOLDE facility using nuclear spectroscopy and in-source laser spectroscopy. A level scheme of 189Tl has been built from $ \gamma$ - $ \gamma$ coincidence relationships and information on the feeding of some excited levels of 189Tl provided by the hyperfine spectra obtained from laser ionization. The half-lives of both the 13/2+ and 3/2- 189Pb isomers have been estimated to be T 1/2 = 50±3 s and T 1/2 = 39±8 s, respectively. Calculations have been performed for different oblate and prolate nuclear deformations using an axial-rotor coupled to one-quasiparticle model, a structure has been suggested for the low-lying levels of the 189Tl nucleus.

Published online 7 August 2007; Low-spin states of $^{182}Ir$ were populated through the $\beta^+/EC$ decay of $^{182}Pt$. Two strong $E2$ transitions were observed for the first time: a 25.7keV transition in $^{182}Ir$ and a 34.0keV transition in Re of probable mass A = 178. Spin and parity, $I^\pi = 3^+$, are firmly assigned to the $^{182}Ir$ ground state (g.s.). For the excited states, the parity is established and the spin determined or restricted. These assignments support most of the interpretations of the level structure previously suggested. The systematics for the known $5^+ \to 3^+$ transitions in $\pi h_{9/2} \bigotimes ν 1/2^-[521]$ bands is presented. Using a semi-microscopic two-quasiparticle axial-rotor coupling model, particle configurations have been attributed or suggested for most of the coupled states lying at low energy in $^{182}Ir$.

Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path $5d^{7}6s ^{2}^{4}F_{9/2} \to 5d^{7}6s6p ^{6}F_{11/2}$ at 351.5nm were measured for $^{182-189}$Ir, $^{186}Ir^{m}$ and the stable $^{191,193}$Ir. The nuclear magnetic moments μI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of μI was experimentally determined for the first time for the masses 182≤A≤189 and the isomeric state $^{186}Ir^ m$ . The spectroscopic quadrupole moments of $^{182}$Ir and $^{183}$Ir were measured also for the first time. A large mean square charge radius change between $^{187}$Ir and $^{186}Ir^g$ and between $^{186}Ir^m$ and $^{186}Ir ^g$ was observed corresponding to a sudden increase in deformation: from β2 ≃ + 0.16 for the heavier group A = 193, 191, 189, 187 and 186m to β2 ≥ + 0.2 for the lighter group A = 186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the π3/2+[402] orbital for the heavier group and with the π1/2-[541] orbital stemming from the 1h _9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments.

Laser spectroscopy based on resonant ionization of laser-desorbed atoms has been used to study the neutron-rich tellurium isotopes with the COMPLIS facility at ISOLDE-CERN. Isotope shifts and hyperfine structures of several neutron-rich Te isotopes: $^{120−136}$Te and $^{123 m−133 m}$Te have been measured. From the hyperfine structure we have extracted magnetic and quadrupole moments. Changes in the mean square charge radii have been deduced and their comparison with the known data for the other elements near Z = 50 is presented. The experimental $\delta$ values are compared with those obtained from relativistic mean field calculations.

A direct deconvolution method has been developed to extract lifetimes from delayed-coincidence curves. After it has been checked on a Monte-Carlo simulation, it has been applied to the lifetime of the 260.5 keV level in 187 Pt . In combination with the standard re-convolution method it gives an estimate of the systematic error, and could be helpful when only approximately matched prompt curves are available.

Nuclear and atomic spectroscopy measurements have provided a great number of data on the neutron-deficient Pt and Hg nuclei. The odd-A Pt and Hg with A 186 is still an open question. The energy of the low-lying levels and the nuclear moments have been calculated in the framework of a semimicroscopic “axial-rotor + 1 quasiparticle” coupling model. The predictions are compared with the experimental data and discussed. The results strongly suggest a prolate shape for the negative-parity low-lying states of the odd-A 187–191Pt and 187–193Hg isotopes.

Low-spin states of 184Au have been studied using the β+/EC decay of 184Hg. γ-ray and conversion-electron singles spectra were recorded with 184Hg mass-separated sources. For γ-γ-t and X-γ-t coincidence measurements, mercury nuclei were produced in the 148Sm + 40Ar reaction and transported by a He-jet system. The electron spectra were recorded from 184Hg sources produced at ISOLDE. A level scheme of 184Au including 48 transitions is proposed. The experimental results are interpreted in the frame of a semi-microscopic axial-rotor-plus-two-quasiparticle model developed in the context of the HF+BCS approximation.

High-resolution measurements of low-energy conversion electrons have been performed in odd and odd–odd nuclei with masses around A=182. The experimental setup, a magnetic spectrograph coupled to a specific tape transport system, is described. Three experiments have been performed and the main results are presented.

Laser spectroscopy measurements have been performed on neutron deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d76s24F9/2 → 5d76s6p 6F11/2 at 351.5 nm have been studied for the 182–189Ir, \(^{186} {\text{Ir}}^\user1{m} \) and 191,193Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the HFS measurements and the changes of the mean square charge radii from the IS measurements. A large mean square charge radius change between 187Ir and 186Ir and between \(^{186} {\text{Ir}}^\user1{m} \) and \(^{186} {\text{Ir}}^\user1{g} \) has been observed.

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc 2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented.

Isotope shift and hyperfine structure measurements have been performed on the short lived184Au nucleus using the COMPLIS apparatus installed at ISOLDE. The charge radius change and the magnetic and quadrupole moments of both isomeric and ground states have been deduced. The184Au ground state appears to be slightly more deformed than the isomeric state.

Resonance ionization spectroscopy (RIS) was performed on desorbed Au, and the complete hyperfine spectrum of both isomeric and ground states of the short lived 184Au nucleus has been recorded from the 5d106s S1y2 ! 5d106p P3y2 optical transition. The nuclear moments of both states and the mean square charge radius changes were measured. The magnetic moments were determined to be m 184g I­5 ­ 12.07s2dmN and m I­2 ­ 11.44s2dmN and the spectroscopic quadrupole moments to be Q 184g s ­ 14.65s26db and Q184m s ­ 11.90s16d b. A difference in the mean square charge radius dkr2 c l184g,184m ­ 20.036s3d fm2 was found. [S0031-9007(97)03992-6]

Excited states in the doubly-odd{sup 184}Au nucleus have been studied by in-beam {gamma}-ray spectroscopy. This nucleus was produced through the fusion-evaporation reactions {sup 165}Ho({sup 24}Mg, 5{ital n}), {sup 170}Yb({sup 19}F, 5{ital n}), and {sup 161}Dy({sup 27}Al, 4{ital n}). Different rotational band structures have been observed and interpreted as specific couplings of proton and neutron single-particle excitations present in neighboring odd Au and Pt nuclei. {copyright} {ital 1996 The American Physical Society.}

A method is described which enables one to deduce a range of possible values for the lifetime of a nuclear level when the delayed coincidence curve is experimentally given and the prompt curve is known only through some of its features. The method still applies when a prompt contribution is present. Experimental data in 184Ir are analyzed, and yield T1/2(293 keV) = 1.1(3) ns, T1/2(70.7)

The $ \beta^{{+}}_{}$ /EC decay of 185Tl was studied at the ISOLDE facility, the $ \gamma$ -rays belonging to 185Hg have been identified and a partial low-spin level scheme of 185Hg has been built. The decay of 185m+gHg was studied at the ISOCELE facility. Conversion electron lines of very low-energy transitions were observed for the first time. Electron data have been obtained for four transitions in 185Au and two transitions in 185Hg . From the analysis performed using an internal energy calibration procedure the energy location of the 185mHg has been determined to be $ E_{IS}= 103.7(4)$ keV. This $ E_{IS}$ value is consistent with that determined independently, $ E_{IS}=94(13)$ keV, using 185m+gHg $ \alpha$ -decay data from literature. New $ \alpha$ particles emitted from 189m+gPb have been detected and their origins determined by in-source laser spectroscopy at the ISOLDE facility. $ \alpha$ - $ \gamma$ coincidence results have served to locate the $ 13/2^{+}$ isomeric state of 189Pb at $ E_{IS}=40(4)$ keV. This latter $ E_{IS}$ value added to $ \alpha$ -decay data from literature have allowed the energy location of the $ 13/2^{+}$ isomeric states of 193Po and 197Rn at 95(7)keV and 194(12)keV, respectively. The nuclear structure of the isomeric and ground states in the nuclei of the three $ \alpha$ -emitter chains starting with 195m+g, 197m+g, 199m+gRn are discussed.

A new experimental setup PILIS II has been installed on-line with the ISOCELE isotope separator (IPN, Orsay). The mass-separated ions are slowed from 30 kV to 500 V and implanted on a graphite collecting disk. The atoms are then thermally desorbed at the implantation region by Nd: YAG laser pulses and selectively ionized by three laser beams. The ions created are mass identified by a time-of-flight (TOF) system. Two versions of the TOF system with accelerating voltages of 1.5 and 30 kV were used to carry out hyperfine structure measurements. With the 30 kV system we obtained an overall detection efficiency of 1.4 × 10−5. First measurements were performed on very light gold and platinum isotopes. It has been shown that PILIS II is well adapted to study very short half-life isotopes ( T 1 2 ∼ 1 s ).

Changes in mean-square charge radius δ〈r2〉, and magnetic dipole moments μ1 have been measured for a series of neutron-deficient gold isotopes between A = 186 and 196, and for neutronrich 198,199Au, using the PILIS system on-line with the ISOCELE mass separator. These measurements confirm the existence of the shape transition between A = 186 and 187. The measured μ1 values have been compared with calculations using Nilsson, and symmetric-rotor-plus-quasiparticle models. The results are consistent with the interpretation that 186Au is prolate, and that the heavier isotopes have oblate, or possibly triaxial deformation.

Laser spectroscopy measurements have been carried out on the neutron-rich tin isotopes with the COMPLIS experimental setup. Using the $5{s}^{2}5{p}^{2\phantom{\rule{0.3em}{0ex}}3}{P}_{0}\ensuremath{\rightarrow}5{s}^{2}5p6s\phantom{\rule{0.3em}{0ex}}{}^{3}{P}_{1}$ optical transition, hyperfine spectra of $^{126\ensuremath{-}132}\mathrm{Sn}$ and $^{125,127,129\ensuremath{-}131}\mathrm{Sn}{}^{m}$ were recorded for the first time. The nuclear moments and the mean square charge radius variation ($\ensuremath{\delta}\ensuremath{\langle}{r}_{c}^{2}\ensuremath{\rangle}$) were extracted. From the quadrupole moment values, these nuclei appear to be spherical. The magnetic moments measured are thus compared with those predicted by spherical basis approaches. From the measured $\ensuremath{\delta}\ensuremath{\langle}{r}_{c}^{2}\ensuremath{\rangle}$, the absolute charge radii of these isotopes were deduced in particular that of the doubly magic $^{132}\mathrm{Sn}$ nucleus. The comparison of the results with several mean-field-type calculations have shown that dynamical effects play an important role in the tin isotopes.

Laser spectroscopy based on resonant ionization of laser-desorbed atoms has been used to study the neutron-rich tellurium isotopes with the COMPLIS facility at ISOLDE-CERN. The isotope shift and the hyperfine structure of several neutron-rich Te isotopes: $^{120–136}$Te and $^{123m–133m}$Te have been measured. From the hyperfine structure and the isotope shift we can extract the magnetic and quadrupole moments and the change in the mean square charge radius respectively. The mean square charge radii of the even-even isotopes have been deduced and their comparison with the known data for the other elements near Z=50 is presented. The experimental $\delta$ is compared with that obtained from the relativistic mean field calculations.

Laser spectroscopy measurements have been carried out on the very neutron-rich tin isotopes with the COMPLIS experimental setup. Using the 5s 2 5p 2 3 P 0 → 5s 2 5p6s 3 P 1 optical transition, hyperfine spectra of 126–132 Sn and 125 m ,127 m ,129 m –131 m Sn where recorded for the first time. The variation of the mean square charge radius ( δ 〈 r 2 〉 ) between these nuclei and the nuclear moments of the isomers and the odd isotopes were thus measured. From the quadrupole moments values, all these nuclei appear to be spherical. The experimental magnetic moments are thus compared with the Schmidt values calculations. Moreover, the measured δ 〈 r 2 〉 are compared with several mean field calculations.

Laser spectroscopy measurements have been carried out on the very neutron-rich tin isotopes with the COMPLIS experimental setup. Using the 5s 25p 23P 0 → 5s 25p6s 3P 1 optical transition, hyperfine spectra of 126-132Sn and 125m, 127m, 129m-131mSn where recorded for the first time. The variation of the mean-square charge radius ( δ〈r 2〉) between these nuclei and nuclear moments of the isomers and the odd isotopes were thus measured. An odd-even staggering which inverts at A = 130 is clearly observed. This indicates a small appearance of a plateau on the δ〈r 2〉 which has to be confirmed by measuring the isotope shift beyond A = 132.

We try to determine to what extent an “axial prolate rotor +1 or 2 quasiparticle model” succeeds in describing the transitional odd and odd-odd Ir and Au nuclei. The relative location of the excited states, as well as the properties of the ground and isomeric states, particularly the magnetic and spectroscopic quadrupole moments, is compared to the predictions of the model.

Laser spectroscopy measurements have been carried out on very-neutron-deficient platinum isotopes with the COMPLIS experimental setup. Using the ${5d}^{9}{6s}^{3}{D}_{3}\ensuremath{\rightarrow}{5d}^{9}{6p}^{3}{P}_{2}$ optical transition, hyperfine spectra of ${}^{182,181,180,179,178}\mathrm{Pt}$ and ${}^{183}{\mathrm{Pt}}^{m}$ were recorded for the first time. The variation of the mean square charge radius between these nuclei, the magnetic moments of the odd isotopes, and the quadrupole moment of ${}^{183}{\mathrm{Pt}}^{m}$ were thus measured. A large deformation change between ${}^{183}{\mathrm{Pt}}^{g}$ and ${}^{183}{\mathrm{Pt}}^{m},$ an odd-even staggering of the charge radius, and a deformation drop from $A=179$ are clearly observed. Comparisons are made with microscopic theoretical predictions, in particular Hartree-Fock-Bogoliubov calculations using the Gogny force.

Laser spectroscopy measurements have been performed on neutron-deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d76s2 4F9/2→5d76s6p 6F11/2 have been studied for the 182–189Ir, 180Irm and 191,193Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the hyperfine splitting measurements and the changes of the mean square charge radii from the isotope shift measurements. A large deformation change between 187Ir and 186Ir and between 186Irm and 186Irg has been observed.

International audience; COMPLIS is an experimental facility designed to carry out spectroscopic studieson radioisotopes produced by disintegration of elements available at CERN's Booster-ISOLDEon-line isotope separator. During recent series of experimental runs, hyperfine structuremeasurements have yielded information on nuclear moments and deformations of platinum andiridium isotopes. For the first time, population by a-decay from Hg was exploited toinvestigate 178-18lpt - the most neutron-deficient Pt isotopes yet studied. Successfulmeasurements have recently been carried out on 182-189lr

Deformation changes δβ have been found out between isomeric and ground states of the 183Pt and 184Au isotones. Atomic spectroscopy measurements by laser were carried out using the COMPLIS setup. Hyperfine structure (HFS) spectra and isotope shift (IS) were obtained for the 5d96s 3D3→5d96p 3P2 and 5d106s 2S1/2→5d106p 2P3/2 optical transitions in Pt and Au atoms respectively, providing deformation parameters β and nuclear moments μ and Qs. The influence of the proton-neutron coupling on the δβ value in 184Au relatively to its isotone 183Pt has been determined. Besides, the h9/2 proton state that is decoupled from the core in 183,185Au, becomes the 3/2[532] state (h9/2 parentage) strongly coupled in the doubly-odd 184Au nucleus.

The M3 transitions linking the ν 7 2 [514] and ν 1 2 [521] states in 78183Pt105 and 76181Os105 have been searched by high-resolution conversion-electron measurements. The reduced M3 transition probabilities have been estimated and compared to the values obtained in neighbouring isotones (74179W105 and 79184Au105). All the known M3 transitions are presented and their properties discussed, especially as a function of deformation. The present work supports the π h 9 2 ⊗ν 1 2 [521] and π h 9 2 ⊗ν 7 2 [514] particle configuration assignments proposed for the 184Au isomeric and ground states, respectively.

Low-spin states of 182Ir populated through the β+EC decay of 182Pt were studied using the ISOCELE facility. A low-spin level scheme has been established. Using a semi-microscopic rotor-plus-two-quasiparticle model developed in the context of the HF + BCS approximation, the influence of the Vpn interaction on the relative energy location of excited states has been studied and the low-spin states located at low energy in 182Ir have been identified. The α-decay energy of 186Au has been corrected to 4907 ± 16 keV.

The decay of181Ir has been studied on-line with mass-separated sources from the ISOCELE facility. The level scheme of181 Os has been established. The isomeric state has been located at 48.9 keV above the ground state. Thus the isomeric and ground states are identified as the 7/2−(T1/2 =2.7 m) and 1/2−(T1/2=105 m) levels respectively.

Gamma-gamma angular correlation measurements have been performed in 187 Pt in order to determine the spin values of the states connected by the highly converted transitions. For one of these transitions, we have determined that the spin values of the initial and final states are different, which implies abnormal M1 multipolarity for this highly converted transition. In that case the deduced penetration parameters have especially high absolute values. Moreover we have determined uniquely the spin value of most of the excited states below 800 keV. The occurence of highly converted transitions in 187 Pt is examined and the low-spin negative-parity levels are discussed in terms of shape coexistence.

γ-γ angular correlation measurements have been performed in 187Pt in order to determine the spin value of the states connected by highly converted transitions independently of their multipolarity. For one of these transitions, we have determined that the spin values of the initial and final states are different, which implies abnormal Ml multipolarity for this highly converted transition.

Low-spin states in doubly-odd184Au have been populated in the β+/EC decay of184Hg produced by bombarding184Sm targets with an 185 MeV40Ar beam. Radioactive Hg nuclei were transported by a He jet system. A new level scheme has been established from γ-γ-t and X-γ-t coincidence measurements. Spin and parity values Iπ=5+, Iπ =2+ and Iπ=3− were assigned to the ground state and the two isomeric states of184Au, respectively. The structure of these states is discussed using B(E1) values.

Half-lives of several low-lying levels in 157, 159, 161 Er have been measured using isotopically separated sources of Tm produced by the ISOCELE facility at Orsay, France. Delayed coincidences between internal conversion electrons or between conversion electrons and gamma quanta have been registered. Absolute reduced transition probabilities of γ-transitions have been deduced and compared with single-particle estimates and theoretical values found from model calculations including the Coriolis mixing of states.

A level scheme has been established for 188 Hg → Au decay which was studied with the on-line isotope separator ISOCELE. Precise conversion-electron measurements were performed with a semicircular magnetic spectrograph. The half-lives of the 16.0, 82.7 and 114.8 keV levels in 188 Au were measured with a lens electron spectrometer and reduced transition rates were deduced. Similarly the half-lives of the 36.1, 113.9, 227.7, 251.5, 288.0 and 363.6 keV levels in 186 Au and of the 28.9 and 171.5 keV levels in 190 Au were measured. Comparison of the reduced e.m. transition rates shows that a 1 + and a 2 − state have respectively the same structure in 186, 188, 190, 192 Au, the same conclusion holding for the 1 − g.s of 188, 190, 192 Au. Additional measurements in 189, 191Hg and 185, 187 Au together with data from the literature enable us to interpret them as a coupling of certain quasiparticle states of neighbouring odd- A nuclei corresponding to oblate shapes. Indications are given that some other negative- and positive-parity states in 188 Au also belong to an oblate system. The nucleus 188 Au appears as the last of a series of doubly-odd gold nuclei where no shape coexistence has, as yet, been observed.

Half-lives of 3 2 + levels in odd-mass Bi nuclei and of 1 2 + levels in 187,191 Au have been measured using mass-separated sources from the ISOCELE separator. The results are T 1 2 ( 201 Bi , 1085 keV level =260 ± 30 ps , T 1 2 ( 203 Bi , 1312.8 keV level )=410 ± 30 ps , T 1 2 ( 205 Bi , 1709.2 keV lev 105 ± 10 ps , T 1 2 ( 207 Bi , 2060.0 keV level )=103 ± 10 ps , T 1 2 ( 187 Au , 19.5 keV level )=7 ± 1 ns and T 1 2 ( 191 Au , 11.2 keV level )=15.5 ± 1.5 ns . An M1 + (9 ± 2)% E2 character has been determined for the 239 keV γ-transition in 201 Bi. Absolute reduced transition probabilities have been deduced and compared with systematics, model predictions and values for corresponding transitions in Tl and Ir nuclei.

Detailed level and decay schemes are presented for the nuclei of A = 116 mass chain. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.

Isotope shift (IS) and hyperfine structure (HFS) measurements have been performed for185, 187, 189, 191, 195Pt using the PILIS (Post ISOCELE Laser Isobar Separator) apparatus installed at the ISOCELE facility. Magnetic and quadrupole moments have been deduced from the HFS results. The charge radius changes determined for these odd nuclei from the IS results, added to the σ values of the even-A nuclei are compared to the results of lattice Hartree-Fock+BCS calculations for asymmetric solutions:185Pt is confirmed to be prolate shaped whereas187, 189, 191Pt are likely triaxial in their ground states.

Level schemes from radioactive decay and reaction studies are presented for all nuclei with mass number A=104. The experimental data have been evaluated and adopted levels, transitions, and other nuclear properties are given.

On analyse brievement les donnees disponibles sur l'effet photoelectrique relativiste dans la couche K et sur la diffusion elastique des electrons relativistes par les atomes. On decrit des experiences sur la distribution angulaire des photoelectrons K produits dans des couches minces (0,92 et 1,39 mg/cm2) de plomb, et on montre qu'elles confirment la correction de diffusion de Hultberg. On etudie l'influence de cette correction sur les mesures de spectroscopie nucleaire par conversion externe.

The 88 keV transition in 109 Ag has been studied by means of a double-focussing magnetic β-spectrometer and of a solid-state Ge(Li) detector. By comparison with the 84 keV transition in 170 Yb, the energy was found to be 88.09±0.03 keV and the internal conversion coefficient α K =12.7±0.9. The internal conversion spectrum has been recorded. All internal conversion measurements agree very well with a pure E3 assignment and theory. The fluorescence yield deduced from the Auger spectrum is ω K =0.834±0.018.

A short review is made of available data on photo-electric effect. The use of a cylindrical source-converter geometry-source coating a cylinder surface and converter stretching along the cylinder axis-in a flat-type β-spectrometer is shown to minimize the absorption of γ-rays in the source and, even at low energies, the influence of the photo-electrons angular distribution anisotropy. Numerical values of the anisotropy correction factor are given for a wide energy range, uranium, lead and tin converters and several geometrical parameters sets.

The capture decay 153 Gd → 153 Eu has been investigated by means of a double-focusing iron-free magnetic β-spectrometer and an electrostatic β-spectrometer equipped for electron-γ coincidences. The photon spectrum has been studied by external conversion, and the method is shown to be reliable even for X-rays. The internal conversion spectrum agrees with a previous measurement. The relative intensities of photons Kα69.7/97.4/103.2 are 346±30/7.5±0.7/100/70±3, which shows a bigger proportion of X photons than values previously available. The 97.4 keV transition in 153Eu is confirmed to be pure E1, and its internal conversion coefficient is α97K = 0.28 ± 0.03. K-capture and branching ratios of the main transitions are determined; the ground-state capture is found more important than previously reported. The deduced value of the decay energy is 237±4 keV.

The decay 95 Zr → 95 Nb was studied by means of an iron-free double-focussing β-spectrometer and Ge(Li) detectors. The photon relative intensity of the 758, 724 and 236 keV transitions was measured. The 236 keV isometric transition was studied with a Zr-free 95m Nb source, and its energy, half-life, α K and α K / α L+M+… were accurately measured. Internal conversion results agree completely with theoretical calculations for an M4 assignment. The number of 724 keV photons per 95 Zr decay and β-branching ratios were deduced.

Isotope shift measurements on even-$A$ Pt isotopes have been obtained from $A=186$ to $A=198$. Charge radius differences have been extracted, and are compared to constrained Hartree-Fock plus BCS calculations. A possible shape transition between $^{186}\mathrm{Pt}$ and $^{188}\mathrm{Pt}$ is discussed.

A system for laser spectroscopic studies on implanted radioactive samples has been developed and installed at the ISOCELE isotopes separator. Mass separated gold isotopes collected in a graphite substrate are desorbed by pulses from a Nd/YAG laser. Three synchronized dye laser pulses produce ions in a resonant ionization process; these are detected and identified in a time‐of‐flight mass spectrometer. Results of isotope shift and hyperfine structure measurements on gold isotopes with A=186, 187, 190, 192, 194, 195 and 196 are presented.

The transitional doubly‐odd iridium nuclei with A=184 and 186 have been studied from the β+/EC decay of the corresponding platinum isotopes using the on‐line mass separator ISOCELE. Configurations can be reasonably Attributed to the low‐lying states of 184Ir in agreement with results already known. On the other hand an E3 transition observed in 186Ir suggests that the known long‐lived 1.7h 2− state is located at 137.5 keV above the 16h 5+ state, raising questions about structure of this latter state.