[en] Full text: Electric monopole (𝘌𝘖) transition strengths are a sensitive probe of nuclear structure and shape coexistence effects. There is a lack of data for 𝘌𝘖 transition strengths in closed shell nuclei that is needed in order to develop our understanding of the mechanisms responsible for the generation of electric monopole strength. The spectroscopy measurements can be challenging, in order to determine an 𝘌𝘖 transition strength the parent state lifetime and electron branching ratio must be measured. The latter requiring simultaneous detections of gamma rays and internal conversion electrons. A series of measurements in the stable nickel isotopes has been performed at the Australian National University. Excited states in ^58,60,62Ni were populated using inelastic-proton scattering. The CAESAR array of Compton-suppressed HPGe detectors was used to measure the (E2/M1) mixing ratio of multiple transitions from angular distributions of gamma rays. The Super-e spectrometer was used to measure 𝘌𝘖 transition strengths for a number of 𝘑-𝘑 transitions. An overview of the experiments will be presented, along with preliminary results for 𝘌𝘖 transition strengths between 𝘑=𝘑 states in the semi-magic nuclei, ^58,60,62Ni and comparison with theory calculations. (author)

[en] Preliminary results from the first experiment of the Stopped Beam RISING campaign are presented. The relativistic projectile fragmentation of a 750 MeV/u beam of ¹⁰⁷Ag populated isomeric states in very neutron deficient nuclei at the proton dripline around mass 80-90. Nuclei were unambiguously identified using the FRagment Separator (FRS) and its ancillary detectors located at GSI. The ions produced were slowed down from relativistic energies by means of an Al degrader and implanted in the centre of the high-efficiency Stopped RISING array. This allowed the identification of new excited states in the N=Z=43 nucleus, ⁸⁶Tc, populated following the de-excitation of a microsecond isomer. Preliminary results of this analysis, as well as previously unobserved isomeric states in ^87,88Tc, are reported. (author)

[en] The preliminary results from the RISING Stopped Beam Isomer Campaign are presented, with specific focus on results of the initial experiment to investigate isomeric decays along the N=Z line around A∼80-90 following the projectile fragmentation of a ¹⁰⁷Ag primary beam at an energy of 750 MeV per nucleon. A description of the technical aspects behind the design of the RISING array is presented, together with evidence for previously unreported isomeric decays in ^87,88Tc and the N=Z nuclei Nb4182 and Tc4386

[en] Identification of near-yrast states in the β -stable nucleus ⁹¹Zr₅₁ has been carried out using the fusion evaporation reaction, ⁸²Se(¹³C, 4n)⁹¹Zr at an incident beam energy of 50 MeV. States above the reported τ =6 μs, I^π = 21/2⁺ isomeric level at E_x = 3167 keV have been identified for the first time in this work, a tentative decay scheme of near-yrast states to excitation energies in excess of 10 MeV has been constructed. These states are of relevance to shell model structures formed via limited valence-space configurations in this semi-magic N = 51 nucleus. (author)

[en] The TRIUMF-ISAC Gamma-Ray Escape- Suppressed Spectrometer (TIGRESS) will consist of 12 large-volume, 32-fold segmented HPGe clover detectors. Each detector is shielded by a 20-fold segmented Compton suppression shield. For performing discrete gamma-ray spectroscopy of light mass nuclei with TIGRESS, we need information about full energy peak efficiency, resolution and lineshape of full energy peaks for high energy gamma-rays. However, suitable radioactive sources having decay gamma-rays of energies greater than ∼ 3.5 MeV are not easily available. So the characteristics of gamma spectrometers at energies higher than 3.5 MeV are usually determined from simulation data. Predictions from GEANT4 simulations (experimentally validated from 0.3 to 3 MeV) indicate that TIGRESS will be capable for single 10 MeV gamma-rays of absolute detection efficiency of 1.5% for backward configuration of the array. It has been observed experimentally that simulation results work well up to certain energies and might deviate at higher energies. So, it is essential to check the validity of simulation results for energies above 3.3 MeV. We have investigated the high energy performance of seven TIGRESS detectors up to 8 MeV

[en] The SPectrometer for Internal Conversion Electrons (SPICE) has been commissioned for use in conjunction with the TIGRESS $\gamma$-ray spectrometer at TRIUMF’s ISAC-II facility. SPICE features a permanent rare-earth magnetic lens to collect and direct internal conversion electrons emitted from nuclear reactions to a thick, highly segmented, lithium-drifted silicon detector. This arrangement, combined with TIGRESS, enables in-beam $\gamma$-ray and internal conversion electron spectroscopy to be performed with stable and radioactive ion beams. Technical aspects of the device, capabilities, and initial performance are presented.

[en] The nuclear structure of ¹²²Xe has been investigated with measurements of the β⁺/EC decay of ¹²²Cs with the 8π γ-ray spectrometer at the TRIUMF-ISAC facility. The data collected have enabled the determination of relative B(E2) values of some low-energy transitions, and the in-band transitions of the excited 0⁺ bands have been observed. As a result, the 2⁺ rotational band members for the 0₂⁺ and 0₃⁺ states have been firmly identified. (authors)

[en] The heavy actinide nucleus "2"5"3No (Z = 102) was studied using the (S)ilicon (A)nd (Ge)rmanium (SAGE) spectrometer allowing simultaneous in-beam γ-ray and conversion electron spectroscopy at the accelerator laboratory of the University of Jyvaeskylae. Using the recoil-tagging technique, γ-electron coincidences have allowed for the extension of the level scheme in the lower-spin region of the yrast band. In addition, internal conversion coefficient (ICC) measurements to establish the multipolarity of transitions have been performed. Measurement of the interband-intraband branching ratios supports the assignment of the Nilsson band-head configuration 9/2"-[734] assigned in previous studies. The study shows the viability of combined in-beam electron and γ-ray spectroscopy down to μb cross sections. (orig.)

[en] The SPICE spectrometer is a new in-beam electron spectrometer designed to operate in conjunction with the TIGRESS HPGe Clover array at TRIUMF-ISAC. The spectrometer consists of a large area, annular, segmented lithium-drifted silicon electron detector shielded from the target by a photon shield. A permanent magnetic lens directs electrons around the photon shield to the detector. Experiments will be performed utilising Coulomb excitation, inelastic-scattering, transfer and fusion–evaporation reactions using stable and radioactive ion beams with suitable heavy-ion detection. Good detection efficiency can be achieved in a large energy range up to 3500 keV electron energy using several magnetic lens designs which are quickly interchangeable. COMSOL and Geant4 simulations have been used to maximise the detection efficiency. In addition, the simulations have guided the design of components to minimise the contributions from various sources of backgrounds

[en] Internal conversion coefficients have been measured for transitions in ¹¹⁰Pd to allow the determination of electric monopole (E0) transition strengths. Excited states were populated through inelastic alpha scattering and the SPICE+TIGRESS detectors at TRIUMF-ISAC-II were used to detect the emitted gamma rays and internal conversion electrons. The E0 transition strengths are found to be small and are consistent with the expectation for transitions from a K = 2 band to the K = 0 ground-state band in the axial rotor model. (orig.)