[en] Nuclear level densities and gamma-ray strength functions are obtained for 56,57^Fe isotopes below the separation energy using the 57^Fe(3^He,αγ)56^Fe and 57^Fe(3^He,3^He¹γ)57^Fe reactions. Step structures in the level densities are explained by a schematic microscopic model comprising single-particle level spacing, seniority-conserving, and seniority nonconserving interactions. An enhancement of more than a factor of ten over common theoretical models of the soft (E_γ < 2 MeV) radiative strength function for transitions in the quasi continuum is observed. A completely different experiment using two-step cascade intensities with soft primary transitions from the 56^Fe(n,2γ) reaction confirm the enhancement

[en] Two-step-cascade spectra of the ¹⁷¹Yb(n, γγ)¹⁷²Yb reaction have been measured using thermal neutrons. They are compared to calculations based on experimental values of the level density and radiative strength function obtained from the ¹⁷³Yb(³He,αγ)¹⁷²Yb reaction. The multipolarity of a 6.5(15) μ_N² resonance at 3.3(1) MeV in the strength function is determined to be M1 by this comparison

[en] The neutron spectrum from the ⁵⁵Mn(d,n)⁵⁶Fe reaction has been measured at E_d = 7 MeV. The level density of ⁵⁶Fe obtained from neutron evaporation spectrum has been compared to the level density from Oslo-type ⁵⁷Fe(³He, aγ)⁵⁶Fe experiment [1]. The good agreement supports the recent results [1, 8] including an availability of a low-energy enhancement in the γ-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy

[en] Unresolved transitions in the nuclear γ-ray cascade produced in the decay of excited nuclei are best described by statistical concepts: a continuous radiative strength function (RSF) and level density yield mean values of transition matrix elements. Data on the soft (E_γ < 3-4 MeV) RSF for transitions between warm states (i.e. states several MeV above the yrast line) have, however, remained elusive

[en] We present data on the soft (E_γ < 3-4 MeV) radiative strength function (RSF) for electromagnetic transitions between warm states (i.e. states several MeV above the yrast line) from two different types of experiments. The Oslo method provides data on the total level density and the sum (over all multipolarities) of all RSFs by sequential extraction from primary-γ spectra. Measurements of two-step-decay spectra following neutron capture yields two-step-cascade (TSC) intensities which are roughly proportional to the product of two RSFs. Investigations on ¹⁷²Yb and ⁵⁷Fe have produced unexpected results. In the first case, a strong (B(M1 ↑) = 6.5 μ_N²) resonance at E = 3.3 MeV was identified. In the second case, a large (more than a factor of 10) enhancement compared to theoretical estimates of the very soft (E_γ (le) 3 MeV), summed RSF for transitions between warm states was observed. A somewhat weaker (factor ∼ 3) enhancement of the RSF in Mo isotopes observed within the Oslo method still awaits confirmation from TSC experiments

[en] Indoor radon concentrations are subject to seasonal variation, which directly depends on weather conditions. The seasonal indoor radon concentrations were measured and the annual effective dose was estimated for the city centre of Eskisehir, Turkey. In order to reflect annual averages measurements were performed over all seasons (winter, spring, summer and autumn) including also the entire year. Measurements were carried out using Kodak-Pathe LR 115 Type II passive alpha track detectors in 220 different houses. A total of 534 measurements including measurements of different seasons were taken between 2010 and 2011. The radon concentrations for winter ranged from 34 to 531 Bq m^-3, for spring ranged from 22 to 424 Bq m^-3 , for summer ranged from 25 to 320 Bq m^-3, and for autumn ranged from 19 to 412 Bq m^-3. Yearly measurements ranged from 19 to 338 Bq m^-3. In this study the average annual effective total dose from radon and its decay products was calculated to be 3.398 mSv y^-1. (authors)

[en] Proton Accelerator (PA) Project is at a stage of development, working towards a Technical Design Report under the roof of a larger-scale Turkish Accelerator Center (TAC) Project. The project is supported by the Turkish State Planning Organization. The PA facility will be constructed in a series of stages including a 3 MeV test stand, a 55 MeV linac which can be extended to 100+ MeV, and then a full 1-3 GeV proton synchrotron or superconducting linac. In this article, science applications, overview, and current status of the PA Project will be given.

[en] The pygmy resonance at 3.3(1) MeV in ¹⁷²Yb has now been established with a strength of B(M1) = 6.5(15)μ²_N and M1 multipolarity. In addition, a strong unexpected enhancement of the radiative strength function has been found at low γ-ray energy in medium light Fe nuclei and also in the heavier Mo nuclei. (author)

[en] Nuclear level densities and radiative strength functions (RSF) in ⁵⁶Fe and ⁵⁷Fe were measured using the ⁵⁷Fe(³He,αγ) and ⁵⁷Fe(³He, ³He(prime)γ) reactions, respectively, at Oslo Cyclotron Laboratory. A low-energy enhancement in the RSF below 4 MeV energy was observed. This finding cannot be explained by common theoretical models. In a second experiment, two-step cascade intensities with soft primary transitions from the ⁵⁶Fe(n,2γ) reaction were measured. The agreement between the two experiments confirms the low-energy enhancement in the RSF. In a third experiment, the neutron evaporation spectrum from the ⁵⁵Mn(dn,N)⁵⁶Fe reaction was measured at 7-MeV deuteron energy at John Edwards Accelerator Laboratory at Ohio University. Comparison of the level density of ⁵⁶Fe obtained from the first and third experiments gives an overall good agreement. Furthermore, observed enhancement for soft γ rays is supported by the last experiment

[en] Radon concentration measurements were performed in the city Eskisehir, Turkey in order to quantify seasonal variation. Using the assumption that indoor radon concentrations exhibit annual cyclic behavior, Pinel's methodology was employed to obtain seasonal correction factors (SCFs). A total of 142 dwellings had radon concentration data for each season that enabled to obtain annual average radon concentrations. Estimated SCFs were applied to each of the 142 dwellings to assess the validity of the factors. The results demonstrate that even in a very small region significant variation in radon concentrations of different dwellings can be observed, and that a good care should be taken in applying SCFs to a short-term radon measurement to obtain average annual radon concentration. (authors)