D. Ivanova's research while affiliated with Medical University of Sofia and other places

Publications (14)

Article
The odd-mass Pd99–105 nuclei were studied via Zr90–96(C12,13,xnγ) fusion/evaporation reactions. The beam was provided by the IFIN-HH Tandem accelerator at energies of approximately 50 MeV. Emitted γ rays were detected by the hybrid multidetector system RoSphere. The structure of the low-lying excited states in Pd99–105 and their gamma-decay pattern...
Article
Full-text available
In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of γ-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system produ...
Conference Paper
Full-text available
At the PF1B cold neutron beam line at the Institut Laue Langevin, the EXILL array consisting of EXOGAM, GASP and ILL-Clover detectors was used to perform (n,g) measurements at very high coincidence rates. About ten different reactions were measured in autumn 2012 using a highly collimated cold neutron beam. In spring 2013, the EXOGAM array was comb...
Article
Full-text available
A smooth onset of collectivity in 88,92,94,96Kr has been determined from reported B(E2; 2+1→ 0+1) and E(2+1) values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the B(E2; 2+1→ 0+1) value in 90Kr, which was produced by cold-neutron-induced fission of 235U....
Conference Paper
Full-text available
At the PF1B cold neutron beam line at the Institut Laue Langevin the EXILL array consisting of EXOGAM, GASP and LOHENGRIN detectors was used to perform (n,γ) measurements under very high coincidence rates. About ten different reactions were then measured in autumn 2012. In spring 2013 t he EXOGAM array was combined with 16 LaBr3(Ce) scintillators i...
Article
This is an open article distributed under the terms of the Creative Commons Attribution Licence 4.0
Article
Full-text available
New positive-parity states, having a band-like structure, were observed in 105Ru. The nucleus was produced in induced fission reaction and the prompt gamma-rays, emitted from the fragments, were detected by the EUROBALL III multi-detector array. The partial scheme of excited 105Ru levels is analyzed within the Triaxial-Rotor-plus-Particle approach.
Article
New positive-parity states, having a bandlike structure, were observed in Ru-105. The nucleus was produced in an induced fission reaction, and the prompt gamma-rays, emitted from the fragments, were detected by the EUROBALL III multidetector array. The partial scheme of excited Ru-105 levels is analyzed within the triaxial-rotor-plus-particle appro...
Article
The half-life of the yrast Iπ=2+ state in the neutron-rich nucleus 188W has been measured using fast-timing techniques with the HPGe and LaBr3:Ce array at the National Institute of Physics and Nuclear Engineering, Bucharest. The resulting value of t1/2=0.87(12) ns is equivalent to a reduced transition probability of B(E2;21+→01+)=85(12) W.u. for th...
Data
Full-text available
The neutron-rich nucleus 117 Rh was synthesized in the fission of relativistic 238 U beam produced at the GSI laboratory in Darmstadt, Germany. An isomeric state with t 1/2 = 138(17) ns decaying by a single γ-ray was observed, providing the first information on the excited states in this nucleus. The experimental data is discussed in terms of syste...
Article
The 7 Li+ 130 Te reaction was used to populate excited states in 132 Te and 134 Xe. The experiment at the Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania, used an array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (LaBr 3 (Ce)) de-tectors to measure sub-nanosecond half-lives using fast-t...
Conference Paper
7Li induced-reactions have been used with a 186W target to populate nuclei around A∼180−190 at the National Institute of Physics and Nuclear Engineering in Bucharest, Romania. An array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (LaBr3:Ce) detectors have been used to measure sub-nanosecond half-lives with fast-timing techniqu...

Citations

... New experimental results on 90 Sr, 92 Sr, 94 Sr, and 96 Sr nuclei were obtained from measurements of γ rays following spontaneous fission of 252 Cf and neutron-induced fission of 235 U, performed using the Gammasphere [20] and the Exogam at Institut Laue Langevin (EXILL) [21] arrays of anti-Compton Spectrometers, respectively. The two experiments provided significantly higher number of triple-γ coincidences, compared to the Eurogam study [18], especially for 90,92 Sr isotopes. ...
... [22], astrophysics or nuclear related applications. In order to cover all the requirements for the different experimental proposals the campaign was scheduled for an n-γ measurement on 17 stable targets in total, to investigate nuclei near the valley of stability [23] and a neutron induced fission part for the actinides 235 U and 241 Pu for measurements on the corresponding fission products in the β − unstable region around neutron number 50-60 for the light fission fragments and around neutron number 80-90 for the heavy fission fragments respectively. ...
... For this count rate the pile-up probability is low. The detector setup was part of the EXILL (EXogam at ILL) [34] (n, γ) campaign [36]. For the experiment, eight Exogam HPGe Clover detectors were available. ...
... More details about this experiment, and other fission products produced in it, are published in Refs. [19][20][21]. ...
... The neutron flux at the target position was approximately 9 × 10 7 n/cm 2 s [15,16]. Prompt γ rays from the fission fragments were detected using a hybrid array of HPGe and Ce-doped LaBr 3 detectors, the EXILL&FATIMA spectrometer [17,18]. The EXILL array [19] was composed of eight BGO-shielded EXOGAM Clover detectors [20], each one consisting of four HPGe crystals. ...
... In contrast to the sharp onset of quadrupole deformation observed in Sr (Z = 38) and Zr (Z = 40) isotopes, when going from neutron number N = 58 to N = 60, a much smoother development of collectivity has been reported along the krypton (Z = 36) isotopic chain, beyond N = 50. This follows from a complete systematic investigation of B(E2; 2 + 1 → 0 + 1 ) transition probabilities, obtained from Coulomb excitation experiments using the MINIBALL γ -ray array at the REX-ISOLDE facility [166,167] and, in the case of 90 Kr, via electronic γ -γ timing (fast-timing) technique performed during the neutron-induced fission EXILL campaign, with the FATIMA spectrometer [168]. Isomers are reported in 94,95 Kr only [165,169]. ...
... In the even-even isotopes, rotational bands have been established up to moderate spins and shape transitions have been identified, as well as K-isomeric states associated with well-deformed, axially symmetric, prolate shapes [14][15][16][17]. Figure 1 presents some key systematic trends in the tungsten isotopes between 176 ≤ A ≤ 188 [7][8][9][10][11][12][13]. Energy systematics [18], as well as known B(E2; 2 + 1 → 0 + 1 ) values [19,20], indicate that 186 W, at N = 112, lies beyond the maximum axial deformation and is softening in shape [4]. ...
... The investigation of the neutron-rich Zr isotopes towards N=70 is crucial for the predicted shell quenching of N=82 at Z=40 [67]. These previously inaccessible nuclei from that region are under shell-model analysis and experimental goals were initiated within the RISING project [119,120] and continued at RIKEN RIBF [121]. On the other hand the discussion of the shell quenching has already been initiated with the example of 130 Cd [122]. ...
... The adopted value is the average of results of 1 and 2. See text for details. Nucleus E x J π Presemt work Ref. [25] Ref. [26] Ref. [27] Ref. [28] Ref. [29] Ref. [ the two out of these four methods (1 and 2) are independent measurements. The latter results could be used to find the adopted lifetime for the 4 + 1 level of 132 Te by averaging the resultant values. ...