New cross-section measurements for the (n, 2n), (n, p), and (n, α) reactions on bromine in the 14 MeV region with detailed uncertainty quantification

Measurement of the cross-sections of the ⁷⁹Br(n, 2n)⁷⁸Br, ⁸¹Br(n, p)^81mSe, ⁸¹Br(n, α)⁷⁸As, and ⁷⁹Br(n, α)⁷⁶As reactions was performed at specific neutron energies, precisely, 13.5±0.2, 14.1±0.2, 14.4±0.2, and 14.8±0.2 MeV, relative to the standard ⁹³Nb(n, 2n)^92mNb and ²⁷Al(n, α)²⁴Na reference reactions using offline γ-ray spectrometry and neutron activation. Monoenergetic neutrons were generated at the China Academy of Engineering Physics via a ³H(d, n)⁴He reaction using the K-400 Neutron Generator equipped with a solid ³H-Ti based target. The activity of the reaction produce was obtained using a high-purity germanium detector. The cross-sections of the (n, 2n), (n, p), and (n, α) reactions on the bromine isotopes were measured in the 13–15 MeV neutron energy range. The covariance analysis approach was employed for a thorough inspection of any uncertainties within the measured cross-section data. A discussion and comparison of the observed outcome were carried out with previously published data, especially with the results of the JENDL-4.0, JEFF-3.3, TENDL-2019, and ENDF/B-VIII.0 data libraries, along with the theoretical excitation function curve derived by employing the TALYS-1.95 program. Improved cross-section restrictions for the investigated processes in the 13–15 MeV neutron energy range will be obtained using the current findings, which will help to raise the caliber of associated databases. Furthermore, the parameters of relevant nuclear reaction models can be verified using this data.     

Isomeric yield ratios of the (γ, n) and (n, 2n) reactions on nuclei of 110Pd, 142Nd, and 144Sm

The isomeric yield ratios of the (γ, n) and (n,2n) reactions on nuclei of ¹¹⁰Pd, ¹⁴²Nd, and ¹⁴⁴Sm are measured by the induced radioactivity method. The energy dependence of the isomeric yield ratios of the photonuclear reactions ¹¹⁰Pd(γ, n)^{109m, g} Pd, and ¹⁴²Nd(γ, n)^{141m, g} Nd, and ¹⁴⁴Sm(γ, n)^{143m, g} Sm is investigated in the energy range 14–35 MeV. The results are compared to other published experimental data.     

Study on the Lorentz detuning and tuning of β=0.3, 352 MHz spoke cavity

The superconducting spoke cavity has been proposed to accelerate the proton in the low energy section of the high power proton linac for the Accelerator Driven Sub-critical System in China. In this paper, the basic geometric and RF parameters of a β=0.3, 352 MHz spoke cavity are given, and the Lorenz detuning and tuning are presented.     

CrHn(n=0,+1,+2)分子及离子的势能函数

用原子分子反应静力学原理推导出CrHⁿ(n=0，+1，+2)的电子状态及其离解极限. 对H原子采用6-311++G^**基组，对Cr原子采用SVP(split valence polarization)全电子基组，用B3PW91方法计算了它们的平衡几何、电子状态，在此基础上分别计算CrH，CrH⁺的Murrell-Sorbie解析势能函数和CrH²⁺的解析势能函数及其对应的力常数、光谱参数，理论计算值与实验值和文献计算值符合较好. 从离解极限和通道解释了不同的势能函数形状. 计算表明：CrH⁺的势能曲线均具有对应于稳定平衡结构的极小点，说明CrH⁺可稳定存在. 而CrH²⁺离子的势能曲线对应于不稳定的排斥态，说明CrH²⁺是不稳定的. 关键词： n(n=0')" href="#">CrHⁿ(n=0 +2) 势能函数 光谱参数 稳定性     

Perturbation study via rotational-resolved spectrum in the triplet band d3Δ-a3∏(2, 1) of CO

The triplet band d³Δ-a³∏ (2, 1) of the CO molecule in the near infrared region of 12350--12850cm^-1 has been observed and analysed by taking into account the perturbation interaction between the d³Δ(v = 2) and a³∏ (v = 9) states. The most perturbed lines and most precise perturbation parameters, \alpha₂ and \beta₂, and electronic perturbation constants,\xi _\e and \eta _\e , for the d³Δ (v= 2) and ³∏ (v = 9) states have been obtained.     

Coherent spectroscopy of the 87RbFg=1→ Fe=0 closed transition

This paper has observed linewidth narrowing of dark states in rubidium cell by using the Hanle configuration. The reduction of the coherent resonance width under the transition of ^87Rb Fg = 1 → Fe = 0 is observed and the qualitative explanation about its mechanism is presented. Multiple subnatural width dips are obtained with a linearly polarized laser beam for the transitions of ^87Rb Fg = 1→Fe = 0, 1, 2. The feature of negative and positive slope, namely dispersionlike feature, is observed in the transmitted light.     

Study of hot bands in the B2Σ+u-X2Σ+g system of C-2 anion

Optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy was employed to observe the visible absorption spectra of the B^2Σ^+_u-X^2Σ^+_g electronic transition of C^-_2. Four hot bands (0,1), (1,2), (2,3) and (3,4) have been observed and the band (3,4) is measured directly for the first time, so far as we know, by absorption. A rotational analysis was carried out to obtain molecular constants. With the Franck－Condon principle and the vibrational Boltzmann distribution, we have estimated the vibrational temperature of C^-_2 to be about 3000K.     

The absorption spectrum of the (1, 0), (3, 1) and (4, 2) bands in the cΣg–aΣu system of He2 eximer

The near-infrared absorption spectrum of He₂ has been recorded in the range of 12 090–13 300 cm⁻¹ using the optical heterodyne concentration modulation spectroscopy. Fifty-nine He₂ spectral lines were assigned to the (1, 0), (2, 0), (3, 1) and (4, 2) bands in the c³Σ_g⁺–a³Σ_u⁺ system and a non-linear least-squares fitting was performed to get the improved molecular constants for the levels (υ = 1, 3 and 4) in the upper electronic state.     

The laser-intensity dependence of the photoassociation spectrum of the ultracold Cs2（6S1/2 ＋ 6P1/2） 0＋ long-range molecular state

The high-resolution photoassociation spectrum of the ultracold cesium molecular 0＋ state below the 6S1/2 ＋ 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].     

Structure and analytical potential energy function for the ground state of the BCx (x=0, －1)

In this paper, the electronic states of the ground states and dissociation limits of BC and BC- are correctly determined based on group theory and atomic and molecular reaction statics. The equilibrium geometries, harmonic frequencies and dissociation energies of the ground state of BC and BC- are calculated by using density function theory and quadratic CI method including single and double substitutions. The analytical potential energy functions of these states have been fitted with Murrell-Sorbie potential energy function from our ab initio calculation results. The spectroscopic data （αe, ωe and ωeχe） of each state is calculated via the relation between analytical potential energy function and spectroscopic data. All the calculations are in good agreement with the experimental data.     

Lattice dynamics and the ferroelectric phase transition in ordered Pb2B′B″O6 (B′ = Ga, In, Lu; B″ = Nb, Ta) solid solutions

The lattice vibration spectrum, rf permittivity, and dynamic Born charges have been calculated for ordered Pb₂ B′B″O₃ (B′=Ga, In, Lu; B″=Nb, Ta) solid solutions in terms of the generalized Gordon—Kim model. It has been shown that all compounds exhibit a ferroelectric instability and that the frequencies of “soft” ferroelectric modes are close in magnitude. The ferroelectric phase-transition temperatures and the spontaneous polarization in the ferroelectric phase of the solid solutions under consideration have been calculated by the Monte Carlo method using the model Hamiltonian in the local mode approximation. The transition temperature is found to increase with increasing atomic number of the B′ ion.     

Absorption spectrum of the (2, 1) band in the AПi-XΣ system of CS cation

The spectrum of CS⁺ cation was recorded in the 12,235-12,600 cm⁻¹ region by employing optical heterodyne velocity modulation absorption spectroscopy. In combination with simultaneous measurement of optical heterodyne concentration modulation absorption spectroscopy, the spectral lines of CS⁺ blended with the neutral CS lines were identified and extracted from the observed spectra. One hundred and eighty-two spectral lines of CS⁺ were assigned to the (2, 1) band in the A²П_i-X²Σ⁺ system and the improved molecular constants of the upper level (υ = 2) in the A²П_i state were derived by nonlinear least squares fitting.     

Confrontation of nucleus deformation and multipole mixture parameters in (2+0 n ?2+01) transitions with rotational band structure for K π = 0 2+ and 0 3+

The difference of the energies of levels Δ _n = E _lev(2⁺0 _n ) − E _lev(0⁺0 _n ) at n = 1, 2, and 3 and the multipole-mixture parameter δ for (2⁺0₂−2⁺0₁) and (2⁺0₃−2⁺0₁) transitions are contrasted against the structure of the K ^π = 0₂⁺ and 0₃⁺ rotational bands that was calculated on the basis of the quasiparticle-phonon model. The values of (Δ₂ − Δ₁), (Δ₃ − Δ₁), and (Δ₂ − Δ₃) are found to correlate with the sign of the parameter δ and with the calculated structure of the K ^π = 0₂⁺ and 0₃⁺ bands. Original Russian Text ? A.M. Demidov, L.I. Govor, V.A. Kurkin, I.V. Mikhailov, 2009, published in Yadernaya Fizika, 2009, Vol. 72, No. 2, pp. 236–240.     

Magnetostriction and magnetization of the intermetallic compounds R Fe2 ? x Co x ( R = Tb, Dy, Er) with compensated magnetic anisotropy

The compounds Tb_0.35Dy_0.45Er_0.2Fe_{2 − x} Co _x (0 ≤ x ≤ 2) are synthesized in both polycrystalline and single-crystal states. The composition of the new multicomponent alloys with compensated magnetic anisotropy is calculated in the framework of the single-ion magnetic anisotropy model with allowance for the data on the temperature dependences of the magnetic anisotropy constants for RFe₂ single crystals. The synthesized compounds are characterized using metallographic, chemical, X-ray diffraction, and thermomagnetic methods. A combined analysis of the magnetic and magnetoelastic properties is also carried out. It is established that the high magnetostriction characteristics of the rare-earth intermetallic compounds Tb_0.35Dy_0.45Er_0.2Fe_{2 − x} Co _x with a structure of Laves phases are observed in the region of the spin-reorientational phase transition whose temperature can be varied by properly choosing the Co content. It is found that, in the room-temperature region, the magnetic susceptibility (dλ/dH) of the composition with x = 1.3 reaches levels in excess of the value of dλ/dH for terphenol D due to the compensation of magnetic anisotropy. Original Russian Text ? I.S. Tereshina, S.A. Nikitin, G.A. Politova, A.A. Opalenko, E.A. Tereshina, I.V. Telegina, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 1, pp. 85–90.     

Isotope dependent predissociation in the C 1 Σ + , v =0 and v =1 states of CO

Rotationally resolved spectral lines in the C - X (1, 0) band of carbon monoxide are investigated under high resolution using a coherent vacuum ultraviolet laser source, continuously tunable near 107 nm. Transition frequencies are determined by calibrating against a reference standard of iodine lines, recorded with saturation spectroscopy in the visible range, yielding an absolute accuracy of 0.003 cm^-1 in the vacuum ultraviolet. Improved molecular constants for the excited state are derived and no effects of perturbation are found at the present level of accuracy. Line broadening measurements result in information on the excited state lifetime of the C ¹ Σ ⁺ , v = 1 state for five natural isotopomers of carbon monoxide: τ( ¹² C ¹⁷ O ) = 280 ps, τ( ¹² C ¹⁸ O ) = 210 ps, τ( ¹³ C ¹⁶ O ) = 295 ps, τ( ¹³ C ¹⁷ O ) = 160 ps, and τ( ¹³ C ¹⁸ O ) = 150 ps. Within the accuracy of the present measurements no effects of J-dependent lifetimes were observed, for neither of the isotopomers. In addition direct time domain measurements of the lifetime of the C ¹ Σ ⁺ , v = 0 and v = 1 states of the main isotopomer are performed in a pump-probe experiment using a picosecond VUV-laser, yielding τ( ¹² C ¹⁶ O ) = 1780 ps for v = 0 and τ( ¹² C ¹⁶ O ) = 625 ps for v = 1. For C ¹ Σ ⁺ , v = 0 in ¹²C¹⁶O and ¹³C¹⁶O the same lifetime is found; this lifetime matches experimental values of the oscillator strength and hence supports previous results showing pure radiative decay in this state; the error margins however do not exclude some low level of predissociation. The measurements indicate that the C ¹ Σ ⁺ , v = 0 state of the ¹³C¹⁸O isotopomer is predissociated with an estimated yield of 17% (i.e. above the level of predissociation for ¹²C¹⁶O.) From the combined data predissociation yields upon excitation of the C ¹ Σ ⁺ , v = 1 state are derived, lying in the range 0.84-0.91 for the five less abundant isotopomers; for the main ¹²C¹⁶O isotopomer a strongly deviating predissociation yield of 0.65 is deduced. Received 21 December 2000 and Received in final form 26 March 2001     

Hyperfine structures and isotope shifts of the 5d 4 D 7/2→6p 4 P 5/2 0 transition in Xenon ions

Collinear fast beam-laser spectroscopy has been performed on metastable 5d ⁴ D _7/2 Xenon ions. Hyperfine structure constants for the 6p ⁴ P _5/2 ⁰ level have been derived for¹²⁹Xe:A=?1,634.9±0.9 MHz and¹³¹Xe:A=485.3±0.3 MHz andB=?116.5±2.0MHz. Changes in mean squared nuclear charge radii are derived from the measured isotope shifts.     

Magnetic properties of complex oxides Ba6Ni5 ? xMnxO15 (x = 2, 3, 4) of the A3n + 3mA′nB3m + nO9m + 6n family

The magnetic interactions in the quasi-one-dimensional complex oxides Ba₆NiMn₄O₁₅, Ba₆Ni₂Mn₃O₁₅, and Ba₆Ni₃Mn₂O₁₅ have been investigated using electron paramagnetic resonance and magnetic susceptibility measurements. It has been revealed that, for the Ba₆Ni₂Mn₃O₁₅ and Ba₆Ni₃Mn₂O₁₅ compounds, the magnetic moments are considerably smaller than the theoretical values and depend on the temperature. The results obtained have been interpreted under the assumption that the structure contains Ni³⁺ ions in which the energy level structure can lead to the above anomalies.     

Deexcitation of K π = 0 2+ , 0 3+ , and 21/+ levels by M 1 transitions in nonspherical even-even nuclei

The signs of the experimental values of the multipole-mixture parameters δ are compared with the signs of ℛ = Σa _i μ _i for (2⁺0₂−2⁺0₁) and (2⁺0₃−2⁺0₁) transitions and with the signs of = Σa _i [(μ _i + μ _kν ) or (μ _kπ − 1/2)] for (2⁺2₁−2⁺0₁) transitions in nonspherical even-even nuclei, where a _i is the contribution of the ith pair of quasiparticles to the wave function for 2⁺0₂, 2⁺0₃, and 2⁺2₁ single-phonon states according to the quasiparticle-phonon model and μ is the magnetic moment for the corresponding Nilsson state. Original Russian Text ? A.M. Demidov, L.I. Govor, V.A. Kurkin, I.V. Mikhailov, 2009, published in Yadernaya Fizika, 2009, Vol. 72, No. 2, pp. 228–235.     

Magnetic phase transition and the corresponding magnetostriction of intermetallic compounds RMnsGe2（R=Sm,Gd）

The temperature dependence of lattice constants a and c of intermetallic compounds RMn₂Ge₂ (R=Sm, Gd) is measured in the temperature range 10－800K by using the x-ray diffraction method. The magnetoelastic anomalies of lattice constants are found at the different kinds of spontaneous magnetic transitions. The transversal and longitudinal magnetostrictions of polycrystalline samples are measured in the pulse magnetic field up to 25T. In the external magnetic field there occurs a first-order field-induced antiferromagnetism－ferromagnetism transition in the Mn sublattice, which gives rise to a large magnetostriction. The magnitude of magnetostrictions is as large as 10^-3. The transversal and longitudinal magnetostrictions have the same sign and are almost equal. This indicates that the magnetostriction is isotropic and mainly caused by the interlayer Mn－Mn exchange interaction. The experimental results are explained in the framework of a two-sublattice ferrimagnet with the negative exchange interaction in one of the sublattices by taking into account the lattice constant dependence of interlayer Mn－Mn exchange interaction.