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Alpha elastic scattering angular distributions of the 106 Cd(�,�) 106 Cd reaction were measured at three energies around the Coulomb barrier to provide a sensitive test for the � + nucleus optical potential parameter sets. Furthermore, the new high precision angular distributions, together with the data available from the literature were used to study the energy dependence of the locally optimized � + nucleus optical potential in a wide energy region ranging from ELab = 27.0 MeV down to 16.1 MeV. The potentials under study are a basic prerequisite for the prediction of �-induced reaction cross sections and thus, for the calculation of stellar reaction rates used for the astrophysical process. Therefore, statistical model predictions using as input the optical potentials discussed in the present work are compared to the available 106 Cd

The heat capacities of dipolar fluids are investigated using a thermodynamic perturbation theory approach and the NVT and NpT Monte Carlo simulation methods. The theoretical results are compared to corresponding simulation data. The comparison shows that the applied perturbation theory is appropriate for the heat capacity calculations. As an application, the isobaric heat capacity of ammonia is also studied by the Stockmayer fluid model.

In order to test the reliability of reaction rate calculations in the framework of the Hauser-Feshbach statistical model, the cross sections of Cd-106(alpha,gamma)Sn-110 radiative capture reaction were determined in the energy range close to the Gamow window for the astrophysical p-process scenario. In addition, to reduce the errors in the predictions of the statistical model calculations, the relevant optical potential parameters are to be determined from the angular distribution measurement of the Cd-106(alpha, alpha) Cd-106 elastic scattering reaction at low energies.

The fission probability of U-236 as a function of the excitation energy has been measured with high energy resolution using the U-235(d, pf) reaction in order to study hyperdeformed (HD) rotational bands. Rotational band structures with a moment of inertia of theta = 217 +/- 38 h(2)/MeV have been observed, corresponding to hyperdeformed configurations. From the level density of the rotational bands the excitation energy of the ground state in the third minimum was determined to be 2.7 +/- 0.4 MeV.The excitation energy of the lowest hyperdeformed transmission resonance and the energy dependence of the fission isomer population probability enabled the determination of the height of the inner fission barrier E-A = 5.05 +/- 0.20 MeV and its curvature parameter h omega(A) = 1.2 MeV. Using this new method the long-standing uncertainties in determining the height of the inner potential barrier in uranium isotopes could be resolved. (c) 2005 Elsevier B.V. All rights reserved.

After a short overview of the methods applied for measuring the neutron-skin thickness, we present the recent experimental results for the neutron-skin thicknesses of the 112–124 Sn even-even isotopes and of 208 Pb. We have used inelastic alpha scattering to excite the giant dipole resonance (GDR). The cross section of this process depends strongly on ΔR np /R, the relative neutron-skin thickness. We have also measured the excitation of the spin-dipole resonance (SDR) to deduce the neutron-skin thickness since the summed L=1 strength of the SDR is sensitive to it. The results obtained are in good agreement with the previous experimental and theoretical ones.

The excitation energy spectrum of fission resonances has been measured with high energy resolution using the 235U(d,pf) reaction in order to study hyperdeformed (HD) rotational bands and HD nuclear shapes. The moments of inertia of the rotational bands and the energy of the ground state in the third minimum were determined. Another signature of these highly deformed states, their enhanced α decay, was also observed. By studying cold or compact fission in the 232Th(n,f) reaction around HD resonances, we obtained data for heavy clustering.

Complete angular distributions for the reactions Sn-112,Sn-124(alpha,alpha)(112,124) Sn have been measured at different energies around the Coulomb barrier. Preliminary results for the Sn-112 circle times alpha and Sn-124 circle times alpha potentials at the energy E-c.m. approximate to 19 MeV are presented. The full determination of the a-nucleus potential for both nuclides may also help to understand the behaviour of a-nucleus potentials along an isotopic chain.

An absolute full-energy peak efficiency calibration of a Clover-type composite germanium gamma-ray detector system is presented. The efficiency curve was measured in the energy range of 120 keV–12.2 MeV for the first time, using the combination of proton-capture nuclear reactions and radioactive sources, such as 56Co, 60Co, 66Ga and 152Eu. At high energies gamma-ray pairs from proton resonance capture on 27Al, 23Na, 39K and 11B were employed using evaporated Al, Na2WO4, K2SO4 and LiBO2 targets, respectively. The experimental data were fitted with a single polynomial function on log–log scale using a recently developed method. The add-back factor is found to increase quadratically with the energy, in contrast to the previously suggested linear relationship. The efficiency gain with respect to a single detector is about one order of magnitude at 10 MeV energy.

The intermediate structure of fission resonances of 240Pu was observed with an experimental energy resolution of 7 keV in the excitation energy region of E ∗ =3.8 –5.6 MeV using the 239Pu(d, pf)240Pu reaction. Two-vibrational resonance groups centered at E ∗ =4.6 MeV and 5.1 MeV, and attributed to the excitation of three and four β-phonons, were resolved into individual substates, which could be assigned to the low-spin members of Kπ=0+ superdeformed (SD) rotational bands. In the region of the lower E ∗ =4.6 MeV resonance individual moments of inertia of six well separated bands could be extracted for the first time with values of Θ/ℏ2 around 157 MeV−1, close to that of the ground state band in the second well. From the level density of these Kπ=0+ band heads the excitation energy of the SD ground state was determined to (2.25±0.20) MeV, in agreement with earlier estimates from excitation functions.

Spectroscopic studies in the superdeformed shape isomer of 240Pu using γ-spectroscopy, conversion electron spectroscopy and transmission resonance spectroscopy have been performed. In a high-resolution and high-efficiency γ-spectroscopy experiment the out-of-band decays of several excited superdeformed rotational sequences with K=2− and 1− could be identified together with evidence for a weakly populated 0− octupole band. Surprisingly, no low-lying collective quadrupole excitations could be observed. Complementary information could be obtained in conversion electron measurements in coincidence with isomeric fission, resulting in the first identification of the lowest s-vibrational K=0+ band. For all rotational bands the variation of the moment of inertia with spin could be studied. A predominant population of negative parity states in the second well could be observed, which can be explained by the selective population and depopulation of the second minimum. Complementary transmission resonance measurements have been performed, yielding new information on the fine structure of high-lying (s-)vibrational multi-phonon states. A new method could be established to determine the excitation energy of the fission isomer ground state from measured level densities.

The 233 U(d,pf) 234 U reaction has been studied with high energy resolution. The observed fission resonances in the excitation energy range of 4.75 ≤E ∗ ≤ 5.40 MeV were described as members of rotational bands with rotational parameters characteristic to the hyperdeformed nuclear shape (ℏ 2 /2 θ =2.1±0.2 keV). Information on the K values of the bands has been obtained from fission fragment angular distribution measurements. The level density of the most strongly excited J =3 states has been compared to the prediction of the back-shifted Fermi-gas formula and the energy of the ground state in the third minimum has been estimated to be E III = 3.1 ± 0.4 MeV.

For the determination of the ${}^{144}$Sm-$\ensuremath{\alpha}$ optical potential we measured the angular distribution of ${}^{144}$Sm$(\ensuremath{\alpha}$,$\ensuremath{\alpha})$${}^{144}$Sm scattering at the energy ${E}_{\mathrm{lab}}=20\mathrm{ }\mathrm{MeV}$ with high accuracy. Using the known systematics of $\ensuremath{\alpha}$-nucleus optical potentials we are able to derive the ${}^{144}$Sm-$\ensuremath{\alpha}$ optical potential at the astrophysically relevant energy ${E}_{\mathrm{c}.\mathrm{m}.}=9.5$ MeV with very limited uncertainties.

A particle discriminator exploiting the ballistic deficit effect for pulse shape discrimination has been developed for CsI(Tl) scintillator + PIN photodiode charged-particle detectors. The method is theoretically investigated and it is shown that the figure of merit of the particle separation is mainly governed by the absolute value of the differential quotient of the rise time dependent ballistic deficit. As the actual particle discriminator contains shaping amplifiers, baseline restorer, pile-up rejector and analog-to-digital converters, it directly accepts signals from a charge-sensitive preamplifier, and its outputs deliver the type and the energy of the particles in the form of eight-bit digital codes. The performance of the particle discriminator is characterised by the figure-of-merit measured as a function of the particle energy.

New data for the Sn-112,Sn-12 4(alpha,alpha) (112,124) Sn reaction have been measured and are presently analyzed. Results of the Sn-112 circle times alpha potential at the energy Ec.m approximate to 14 MeV are presented. The determination of this a-nucleus potential may allow a prediction of the Sn-112(alpha,gamma) Te-116 cross section.

Angular distributions of elastically scattered alpha particles were measured for the 34S, 50Cr and 62Ni target nuclei in the energy range 12.8–20.0 MeV. The experimental data were analysed using the phenomenological optical model with the Saxon-Woods form factor; in the case of 34S the squared Saxon-Woods form factor was also applied. Phenomena such as the anomalous energy dependence of the potential near the Coulomb barrier, the discrete ambiguity problem, the low-mass and low-energy limit of applicability of the optical model are discussed using the real volume integral values obtained.

In the present work both the (α,γ) and (p,γ) cross sections on the p‐nucleus 106Cd have been measured in the energy range relevant to the astrophysical p‐process. The results are compared with the predictions of the statistical model calculations implemented with the NON‐SMOKER code using different input parameters. The proton capture cross section has also been measured for 108Cd.The α + 106Cd optical potential, an important input parameter for the 106Cd(α,γ) reaction rate determination, can be determined directly by measuring the deviation from the Rutherford scattering in the 106Cd(α,α)106Cd elastic scattering experiment. This experiment has also been performed in a wide angular range and the results are compared with different global optical potentials.

In order to improve the reliability of statistical model calculations in the region of heavy proton rich nuclei several elastic alpha scattering experiments have been carried out at low bombarding energies on various even‐even and semi‐magic nuclei. The extracted local optical potential parameters can be compared with the predictions of global alpha potentials. A study on 112,124Sn(α,α)112,124Sn has been made to test the global alpha potentials at both the proton and neutron rich sides of an isotopic chain. The present work describes the experimental challenges of high precision scattering experiments at low energy.

UV-B irradiation of intact Synechocystis sp. PCC 6803 cells results in the loss of Photosystem II activity, which can be repaired via de novo synthesis of the D1 and D2 reaction center subunits. A key step in the repair process is the differential transcription of the psbA2 and psbA3 genes, coding for identical D1 polypeptides [Máté et al. (1998) J Biol Chem 273: 17439-17444]. In the present work, we investigated for the first time the effect of UV-B irradiation on the transcription of the psbD1 and psbD2 genes encoding identical D2 polypeptides. By using gene-specific S1 nuclease protection assay we showed differential UV-B induced transcription of the two psbD genes: the level of psbD1 mRNA was increased 1.5-2 fold, whereas the accumulation of psbD2 mRNA was 5-7 fold. The induction of psbD2 transcript accumulation by low intensity light was specific for the UV-B range. UV-A emission from the applied UV source, as well as 100 muE m(-2) s(-1) white light had negligible effect. Increase in the psbD2 mRNA level was observed at very low UV-B intensities, which did not cause damage to the function and protein structure of PS II. Expression patterns of chimeric genes containing the promoter regions of the psbD1, psbD2 genes fused to the firefly luciferase (luc) reporter gene showed similar induction as observed for the endogenous psbD genes. Our findings demonstrate that UV-B radiation induces differential expression of the of the psbD1 and psbD2 genes. We propose that the primarily expressed psbD2 serves as a UV stress gene and participates in a rapid defense response against UV-B stress. This effect is regulated, at least partially, at the level of transcription.

The cross sections for the elastic scattering reactions Sn-112,Sn-124(alpha,alpha)Sn-112,Sn-124 at energies above and below the Coulomb barrier are presented and compared to predictions for global alpha-nucleus potentials. The high precision of the new data allows a study of the global alpha-nucleus potentials at both the proton- and neutron-rich sides of an isotopic chain. In addition, local alpha-nucleus potentials have been extracted for both nuclei and used to reproduce elastic scattering data at higher energies. Predictions from the capture cross section of the reaction Sn-112(alpha,gamma)Te-116 at astrophysically relevant energies are presented and compared to experimental data.

The neutron-skin thickness in Pb-208 was determined by measuring the cross section of the isovector giant dipole resonance (GDR) in inelastic scattering of 196 MeV alpha-particles. From the comparison of measured and calculated cross sections the relative difference of proton and neutron distribution radii (DeltaR(PN)/R-0) was deduced to be 2.2 +/- 1.2%.

UV-B irradiation of Synechocystis 6803 cells inhibits photosystem II activity, which can be restored via de novo synthesis of the D1 (and D2) reaction center subunits. Recently we have shown that of the two psbA genes that encode identical D1 proteins in Synechocystis 6803, UV-B preferentially enhances the transcription of psbA3 compared to that of psbA2 [Máté, Z., Sass, L., Szekeres, M., Vass, I. and Nagy, F. (1998) J. Biol. Chem. 273, 17439-17444]. Here we studied the effect of UV-B on the synthesis of the D1 protein from the psbA2 and psbA3 genes in the P7 mutant of Synechocystis 6803. In this mutant, psbA2 carries the Ala251--Val point mutation, which confers resistance to the photosystem II electron transport inhibitor metribuzin, but psbA3 is the same as in the wild-type. By applying variable chlorophyll fluorescence measurements to distinguish between metribuzin-sensitive and metribuzin-resistant photosystem II centers we quantified the amount of the D1 protein produced from each of the psbA3 and psbA2 genes. When the cells were exposed to UV-B light, the fraction of D1 protein produced from the psbA3 gene was increased from 15-20 to 32-40% of the total D1. This effect was reversible by transferring the cells to visible light. The rate of D1 production from psbA3 increased with increasing UV-B intensities, and was a transient phenomenon at low UV-B levels (0.1 microE x m-2 x s-1). It is concluded that the enhancement of psbA3 gene transcription by UV-B light leads to enhanced D1 protein synthesis from this gene. Our findings demonstrate that the main role of psbA3 transcription activated by UV-B is to increase the size of the psbA mRNA pool available for translation when a rapid repair of the D1 protein is needed under UV-B stress.

Sharp transmission resonances have been observed in the U-235(d, Pf) U-236 reaction. The shapes of the resonances as well as the angular distributions of the associated fission fragments are analyzed together with the data obtained previously for U-234. The resonances are interpreted as being hyperdeformed rotational bands with (h) over bar(2)/2 theta = 1.8(-0.7)(+0.5) and 1.6(-0.4)(+1.0) keV and K values of 1, 2, and 4 for U-234 and U-236, respectively.

Comparing real nuclear physics experiments with principles given by standard textbooks on quantum mechanics one can conclude that the ‘measurement’ concept is actually not used in the practical description of nuclear (and perhaps microphysical) phenomena.

In this work we present the continuation of the reported analysis [1] of the experimentally measured angular distributions of the reaction 106Cd(α, α)106Cd at several different energies around the Coulomb barrier. The difficulties that arise in the study of 106Cd-α-nuclear potential and the so called Family Problem are addressed.

The heat capacities of ferrofluids are investigated using a thermodynamic perturbation theory approach and the NVT and NpT Monte Carlo simulation methods. The systems studied are considered as one-, three-, and five-component dipolar mixtures modeled by the Stockmayer interaction potential. The isochoric and isobaric heat capacities are calculated and compared with the data determined for a monodisperse equivalent of the system.

The electron spectrometer consists of two Si(Li) detectors, two superconducting magnet transporters and auxiliary equipment. The electron transmission reaches 76% (from 4π for two detectors) and is independent of electron energy up to about 1600 keV at the maximum 3.2 T magnetic field of the solenoids. For the sake of background reduction in some on-line experiments baffles were used in front of the detectors. In this case the transmission is 25%–30% in the 150–650 keV electron energy interval. The obtained resolution is 2.5-3 keV (fwhm at 300 keV electron energy).

Excitation functions have been measured at six angles for 24 Mg(α, α) 24 Mg up to E α 4.94 MeV. Multi-level R -matrix analysis was performed for nineteen resonances. More than ha of the determined spin-parities and other resonance parameters are new values. The 24 Mg(α, γ) 28 Si studies of Maas et al. were extended up to E α = 5.13 MeV. Resonance strengths and branchin ratios were determined. The γ-ray angular distribution measurement at E α = 3.79 MeV gives J π = 2 + value for the resonance. A comparison of the results obtained in different reaction channel is given and the possibility of clusterisation in some excited states of 28 Si is discussed.

Excitation functions have been measured at five angles for the 19 F(α, α) 19 F scattering process up to Eα = 3.7 MeV. The yield curves for the 19 F(α, γ) 23 Na , 19 F(α, p 0 ) 22 Ne and 19 F(α, p 1 γ) 22 Ne reactions were also obtained in simultaneous measurements. A multi-level R-matrix calculation was used to analyse the elastic scattering data, yielding parameters for 16 resonances. Sixty resonances corresponding to levels in 23Na were seen in the different reactions. A comparison of resonance energy and total width data is given. The 19 F(α, γ) 23 Na reaction below Eα = 2.3 MeV was studied also with thick-target measurements. Decay schemes are given for two resonances. The α-particle strength is discussed.

The fission probability and the angular distribution of the associated fission fragments have been measured for the235U(d, pf)236U reaction slightly above the top of the inner fission barrier with the aim of disclosing new hyperdeformed states lying in the third minimum of the fission potential. The results are analyzed together with the data obtained from the literature for234U. The experimental resonances are interpreted as being rotational bands with rotational parameters of ħ/2Θ=1.6±0.6 and 1.8±0,8 keV for234U and236U, respectively. TheK=1, 2 and 4 values of the resonances suggest that these rotational bands are built on some higher-lying excited states in the third minimum of the potential well.