40Ca(d, α)38K and isospin

We investigate the ⁴⁰Ca(d, α_{0, 1, 2, 4})³⁸K reactions for E_d = 4.00–4.61 MeV. The α₁ and α₄ transitions are isospin forbidden. The resonant-like structures observed in the α₀, α₁, α₂, and α₄ transitions are consistent with Ericson theory. In addition we can fit a portion of the α₁, data with a few interfering Breit-Wigner resonances. The level parameters for the corresponding ⁴²Sc levels are given.     

Λc5He and Λc9Be charmed nuclei versus Λ5He and Λ9Be hypernuclei

A comparative study is made for _Λc⁵He and _Λc⁹Be charmed nuclei versus _Λ⁵He and _Λ⁹Be hypernuclei. The Λ_c(Λ)+α and Λ_c(Λ)+α+α systems are treated in a microscopic way. Within certain range of the Λ_cN interaction strength, the energy properties of Λ_c+α and Λ_c+α+α are calculated and discussed. Similarity between the energy spectra of the noted charmed nuclei and hypernuclei is suggested.     

Copper ion induced reactions on110-108-106Cd,109-107Ag and110Pd. new rhenium,osmium and iridium isotopes

By⁶³Cu induced reactions on¹¹⁰Cd,¹⁰⁸Cd,¹⁰⁶Cd,¹⁰⁹Ag,¹⁰⁷Ag and¹¹⁰Pd targets, new isotopes were searched in the Ir, Os, Re region. Cross bombardments and excitation function measurements were used to identify newα emitting isotopes:¹⁷⁰Ir (E _α = 6.01 ±0.01 MeV?T _1/2=1.1±0.2s),¹⁶⁹Ir (E _α =6.11±0.01 MeV?T _1/2=0.4±0.1 s),¹⁶⁸Ir (E _α =6.22±0.02 MeV,¹⁶⁸Os (E _α =5.66±0.01 MeV?T _1/2=1.9±0.1 s),¹⁶⁷Os (E _α =5.84 ±0.01MeV ?T ^1/2=0.65±0.15s),¹⁶⁶Os (E _α =6.00±0.02 MeV?T _1/2=0.3 ±0.1 s),¹⁶⁵Os (E _α =6.20±0.02 MeV),¹⁶⁹Re (E _α =5.05±0.01 MeV),¹⁶⁸Re (5.26±0.01 MeV?T ^1/2=5.5 ±0.5 s). Theα-decay measurements are compared to theQ _α values obtained from different mass predictions.     

Finite N=1 SUSY field theories and dimensional regularization

A simple algorithm is proposed to construct finite N=1 SUSY field theories within dimensional regularization. This is achieved by choosing the Yukawa couplings to be y_i=g(αⁱ₀+αⁱ₀ϵ+ϵ+αⁱ₂ϵ²+…), where g is the gauge coupling and the coefficients αⁱ₀, αⁱ₁, etc., are calculated order by order of perturbation theory. It is shown that the theory can be made finite in all orders of perturbation theory.     

The alpha-branching ratios of the188,190,192Pb isotopes

Theα-branching ratios (b _α ) of^192,190,188Pb are measured using mass-separated sources. Different experimental set-ups are used — one detector as well as two detector set-ups — thereby detecting theα particles from the parent and/or viaα decay formed daughter nuclei, theβ-delayed gamma radiation from the parent and/or viaβ decay formed daughter nuclei and the Tl KX rays from electron capture decay. Values forb _α of 6.2(6) 10^?5 and 4.0(4) 10^-3 were found for^192,190Pb respectively. For¹⁸⁸Pb, limits on theb _α values were obtained: 0.03<b _α <0.10. A careful analysis of the previously reportedb _α values showed that the discrepancies in theb _α values were not due to inadequate correction procedures, as was suggested, but to experimental uncertainties in the efficiency determination of the different detection set-ups and to an unreliableβ-decay scheme for¹⁸⁸Pb. Theb _α obtained in this work show that the leadα decay is not faster than the Hgα decay and that there is no need to assume a disappearance of theZ=82 shell closure halfway betweenN=82 andN=126.     

Quantum electrodynamic corrections to the 23S1 → 11S0 + one photon transition rate in helium and helium-like lons

The order (Zα)⁵, α(Zα)⁴, and α(Zα)⁴ log(Zα) energy denominator and recoil corrections to the leading order (Zα)⁴ decay amplitude for the 2³S₁ → 1¹S₀ + one photon transition are considered. It is found that order α(Zα)⁴ terms arise in the individual diagrams but exactly cancel upon summation. In view of the results of this and other recent theoretical work it is concluded that the rates predicted by pure quantum electrodynamics are known to considerable precision. The recent discrepancy between theory and experiment in the decay rate for several helium-like ions appears to have been resolved by placing the detector farther downstream from the foil where the metastable states are produced. At present, all the experimental values are in good agreement with the theory.     

Elastic scattering of α-particles on10B forE α = 5−50 MeV

Experimental data of the elastic scattering ofα-particles on¹⁰B forE _α = 30?50.6 MeV are presented. They are analysed together with the data of a previous measurement forE _α = 5?30 MeV in the frame of the optical model including spin-orbit coupling. The interaction radii of theα-¹⁰B-systems are determined with the Inopin-Ericson model forE _α = 5?50 MeV. The mean free path ofα-particles in¹⁰B is calculated.     

New screening doublets in x-ray satellite spectra

Recent scrutiny of the relevant data available at present on x-ray satellite spectra in theK, L andM regions revealed the existence of two new satellite pairsα″α′ andα″α′ ₃ ′ in theKα satellite group, three pairsα′ ₂ α″,α′ ₂ α^VI andα? α ^IV in theLα satellite group, twoLβ ₂ satellite groups; viz.,β ₂ ^(b) (β ₂ ^I ,β ₂ ^II β ₂ ^(c) ) andβ ₂ ^(c) (β ₂ ^I β ₂ ^II ), two pairsγ′₁ γ′₂ andγ′₁ γ′_2′ in theLγ satellite group and also a pairβ _II β _III in theMβ satellites, which are all found to be governed by the screening doublet relationship,Δ(v/R)^1/2=constant.     

8He Nuclei Stopped in Nuclear Track Emulsion

A nuclear track emulsion (NTE) is exposed to 60 MeV ⁸He nuclei. Measurements of decays of ⁸He nuclei stopped in NTE allow one to evaluate possibilities of α-spectrometry. Thermal drift of ⁸He atoms is observed. Knowledge of the energy and emission angles of α-particles allows one to derive the energy distribution of α-decays Q_2α . The presence of a “tail” of large values Q_2α is established.     

The 56Fe(α, γ)60Ni reaction at excitation energies in the region of the giant dipole resonance

Excitation functions for the ⁵⁶Fe(α, γ₀)⁶⁰Ni and ⁵⁶Fe(α, γ₁)⁶⁰Ni reactions have been measured at 90° to the beam direction over the bombarding energy range 8.0–17.6 MeV. Gamma-ray angular distributions were measured at ten bombarding energies. Excitation functions for the ⁵⁹Co(p, γ₀)⁶⁰Ni and ⁵⁹Co(p, γ₁)⁶⁰Ni reactions were measured over the range E_x = 16.58–16.92 MeV and compared with the (α, γ) data. The angular distribution data indicate that the (α, γ₀) and (α,γ₁) reactions proceed through 1^?, and 1^? and 3^? states, respectively. The (α, γ) excitation functions are discussed with respect to isospin splitting of the ⁶⁰Ni giant dipole resonance. The fine structure observed in the excitation functions is shown to be most probably due to Ericson fluctuations. The gross (α, γ) cross sections are shown to be in reasonable agreement with the results of calculations made using the theory of Hauser and Feshbach assuming excitation of the giant dipole resonance.     

Thermal neutron induced α-particle reaction on64, 65, 67Zn and77Se

The (_n th,α) reaction spectroscopy was done on^{64, 65, 67}zn and⁷⁷Se at the 87 m curved thermal neutron guide of the Grenoble high flux reactor. In each of the⁶⁴Zn(n, α)⁶¹ Ni and⁶⁷ Ni(n, α) ⁶⁴Ni reactions, one line showed up corresponding to anα-particle transition to the first excited state in⁶¹Ni and⁶⁴Ni withσ _α1=11±3 μb and 159±20 μb respectively. In the case of the radioactive⁶⁵Zn(T _1/2=244d) nucleus, two lines showed up corresponding to the ground state and the first excited state transitions in⁶²Ni with large values ofσ _α0=1.0±0.1b andσ _α1=1.0±0.1b. For the⁷⁷Se(n, α)⁷⁴Ge reaction, the ground state and first excited transitions were present withσ _α0=940±20 μb andσ _α1 = 30±5 μb respectively. The spin-parity (J ^π) of the neutron resonance contributing at thermal energy are discussed.     

Alpha decay properties of199Rn and199mRn

Theα-decays of¹⁹⁹Rn (E _α = (6.989±0.010) MeV,T _1/2>300ms) and of^199m Rn (E _α = (7.060±0.015) MeVT _1/2=(61 _?2 ⁺³² ) ms) were identified by anα-α-correlation method. They proceed via separated decay paths to¹⁹⁵Po and^195m Po, respectively. The spins of the involved states are discussed by aid of the shell model, and a tentative spin assignment is given.     

Relationship between the thermal expansion coefficient, plasmon energy, and bond length of ternary chalcopyrite semiconductors

A simple relation between the average bond length and plasmon energy, that is, d=15.30(?ω_p)^−2/3, has been proposed for A^IIB^IVC^V₂ and A^IB^IIIC^VI₂ chalcopyrite semiconductors. The average linear thermal expansion coefficient (α_L) of these semiconductors has been calculated using plasmon energy data. The linear expansion coefficients (α_a) and (α_c) of the lattice parameters a and c, respectively, have also been calculated. The calculated values of d, α_L, α_a and α_c have been compared with the experimental values and the values reported by different workers. A fairly good agreement has been obtained between them.     

High spin states in73Se observed by the reaction70Ge(α,nγ)

⁷³Se has been investigated by the reaction⁷⁰Ge(α, nγ). Gamma excitation functions (E _α=10–16 MeV), gamma angular distributions (E _α=18 MeV) and gamma-gamma coincidences (E _α=15 MeV)) have been taken. A level scheme has been established, spins and partities have been assigned. States of a rotational band on the 151.2 keV (5/2^?) state and an anomalous band have been identified. Nuclear Reaction⁷⁰Ge(α,nγ)E _α=15 and 18 MeV; measuredE _γ,I _γ,γ-γ-coin.,γ-angular distribution,γ-excitation function.⁷³Se deduced levels,J, π. Enriched target, Ge(Li).     

Helium burning of 18O

The ¹⁸O(α, γ)²²Ne capture reaction has been studied at E_α = 0.6?2.3 MeV. The known resonance at E_α = 2.20 MeV has been established and fourteen new resonances have been found in the energy range covered. The E_α = 1.16, 1.32, 1.45, 1.53, 1.87, 1.96 and 2.15 MeV resonances correspond to resonances observed previously in the ¹⁸O(α, n)²¹Ne reaction. The E_α = 0.77, 1.25 and 1.27 MeV resonances represent new compound states in ²²Ne. Information on branching ratios, ωγ values and total widths is reported. Transition strength arguments and analyses of γ-ray angular distribution data together with results from previous work resulted in the most likely J^π assignments for the resonances.The E_α = 1.66 and 1.78 MeV resonances are good candidates for the two J^π = 8⁺ states predicted at E_x ≈ 11–12 MeV and are probably members of the K^π = 0⁺ (ground state) and K^π = 2⁺ rotational bands in ²²Ne.The investigated energy range of E_α together with that of previous work corresponds to stellar temperatures of T = (0.3?4.3) × 10⁹ K. The astrophysical reaction rate determined from these data is compared with predictions based in part on the nuclear optical model. The rate is also compared with that of the competing ¹⁸O(α, n)²¹Ne reaction.     

164Ta,identification of a new isotope

The new isotope¹⁶⁴Ta (T _1/2=13.6(2)s) was produced in the¹²⁷I(⁴⁰Ca, 3n) reaction and transported to a measuring station by helium jet. Decay properties were observed withα, γ, andγ-γ spectroscopy. TheZ assignment of the new isotope was based ongg-X-ray coincidence measurements. The mass assignment was deduced from measured excitation functions. The twoγ rays assigned to the new activity most likely originate from the 4⁺→2⁺→0⁺ decay sequence in¹⁶⁴Hf. A smallα branch, ≦0.016(5)%, with anα decay energy ofE _α=4,625(15) keV was found and assigned to the decay of¹⁶⁴Ta. The deduced upper limit of theα width for this branch,W _α≦0.6(2), is in accordance with those known for neighbouring nuclei.     

Resonances in low energy40Ca(α, α)-scattering and quasimolecular band in44Ti

The elasticα-scattering from⁴⁰Ca has been studied betweenE _α=7.035 MeV and 7.405 MeV. Angular distributions and excitation functions have been measured in 5 keV steps. The data display a resonance atE _α=7.26 MeV which by its width and angular correlation is clearly distinguished from strong Ericson fluctuations in this region. From the analysis of the angular distributions and excitation functions a spinJ ^π=1^? is assigned to this resonance. The resonance parameters areΓ _α=31 KeV,Γ _total=51keV. By its spin and excitation energy this state is interpreted as a member of a quasimolecular band in⁴⁴Ti the higherl-members of which are known from⁴⁰¹Ca(α, α) scattering betweenE _α=18 MeV and 50 MeV. The experimental data are compared with recent microscopic calculations within a fully antisymmetrized reaction theory.     

Study of the reactions31P(α,p)34S and29Si(α,n)32S

The (α,p) reaction on³¹P in the energy rangeE _α=3.25 to 5.25 MeV and the (α,n) reaction on²⁹Si in the energy rangeE _α=3 to 4.8 MeV, have been used to determine nuclear properties of³⁵Cl and³³S respectively. Resonance energies, strengths and partial widths are reported. The analysis of angular distribution measurements yields spin values for 23 resonance levels in³⁵Cl and 14 levels in³³S.     

79Se investigated by the reaction76Ge(α, nγ)

⁷⁹Se has been investigated by the reaction⁷⁶Ge(α, nγ). Gamma excitation functions (E _{α=10?15 MeV)}, gamma angular distributions and gamma-gamma coincidences (both at (E _{α=12 MeV)}, have been taken. A level scheme has been established, spins and partities have been assigned. The results are compared with rotational bands in neighbouring odd Se isotopes. Nuclear reaction⁷⁶Ge(α, nγ)E _α =12 MeV; measuredE _γ,I _γ,γ-γ coincidences,γ-angular distribution,γ-excitation function.⁷⁹Se deduced levels,J, π. Enriched target, Ge(Li).     

Thermal neutron induced charged particle reactions on58,59,61Ni

The thermal neutron induced charged particle spectroscopy on^{58, 59, 61}Ni (target nuclei) was done at the 87 m thermal neutron curved guide of the Grenoble high flux reactor. In the⁵⁹Nu(n, α)⁵⁶Fe reaction two lines showed up corresponding toα-particle transitions to the ground and first excited states in⁵⁶Fe with σ_α0=13.1±1.1 b and σ_α1 =0.188±0.01 b. A value of σ_γα≦13 mb was obtained for the two-step⁵⁹Ni(n, γα)⁵⁶Fe reaction. The technique to unfold theγα-spectrum and to get information on the primary low energyγ-rays is given and the present and our previous data on the¹⁴³Nd(n, γα)¹⁴⁰Ce reaction are analysed. For the⁵⁹Ni(n, p)⁵⁹Co reaction _p0=1.34±0.18b,σ _p1<0.30 b were determined. The cross-sections for the⁵⁸Ni(n,α)⁵⁵Fe and⁶¹Ni(n,α)⁵⁸Fe reactions were σ_α0≦30 Μb and σ_α0≦30 Μb respectively; these andσ _p1upper limit value are about 20–1500 times lower than the existing data. The other results are compared with the existing data and the differences are explained. The experimental data are compared with the values obtained from the statistical model.