M. S. Chowdhury

A study of nuclear structure in 59Ni from the (d, p) reaction on 58Ni

Abstract Level structure in 59 Ni is studied from the (d, p) reaction in 58 Ni using the Aldermaston tandem Van de Graaff accelerator and the multichannel magnetic spectrograph. Angular distributions of protons are measured over the angular range 5°–175° up to an excitation of ≈ 8 MeV and absolute cross sections are measured. The data are analysed in terms of the finite-range DWBA theory of direct reactions and spins, parities and spectroscopic factors are deduced for various levels. The summed spectroscopic factors and the single-quasiparticle energies of the shell-model states are obtained. Properties of the low-lying levels in 59 Ni are compared with predictions based on exact shell-model calculations.

Level structure of 51Cr from the (d, p) reaction on 50Cr

Abstract The level structure of 51 Cr is studied through the 50 Cr(d, p) reaction at E d = 12 MeV using the Van de Graaff accelerator and multi-channel magnetic spectrograph at AERE, Harwell. A total of 174 levels was observed up to E x ≈ 8.1 MeV. The stripping angular distributions are analysed in terms of the DWBA model with NLFR corrections. Spins, parities and spectroscopic factors are obtained for various levels and a sum rule analysis is made. Hauser-Feshbach calculations are done for the non-stripping levels and the levels showing a poor DWBA fit. Finally, the level spectrum is compared with the MBZ and MS models.

Level properties of 50V through the 51V(τ, alpha;) reaction

Abstract The 51 V(τ, α) 50 )V reaction has been studied at E τ = 18.0 MeV using a multichannel magnetic spectrograph. Seventy levels up to an excitation of 9.3 MeV have been observed, including five analogues. The angular distributions have been analysed in terms of the DWBA theory of direct reactions; a sum rule analysis has been made with the spectroscopic strengths so obtained. The effects of non-locality and finite range in the optical potential and of the cut-off radius and optical model parameter sets were also studied. Except for a few levels, the l -assignments agree well with previous neutron pick-up work; some new assignments of l -values are also made. In addition to l = 0, 2 and 3 transitions, a few weak l = 1 transitions were also observed.

Level structure of 47Ti from the (d, p) reaction in 46Ti

Abstract The reaction 46 Ti(d, p) is studied at 10 MeV using the Aldermaston tandem Van de Graaff accelerator and a multichannel magnetic spectrograph. A total of 180 levels are observed up to an excitation of ≈ 7.2 MeV and the stripping angular distributions are analysed in terms of the DWBA theory of direct reactions using the NL/FR optical model potential. Spins, parities and spectroscopic factors are deduced for various levels. Summed spectroscopic factors and quasiparticle energies are obtained for shell model states. Properties of low-lying levels in 47 Ti are compared with the MBZ and Coriolis coupling models and also with those of the isotonic nuclei 45 Ca and 46 Sc.

Nuclear-structure studies of94,96,98,100Mo from the (t, p) reactions atEt=12 MeV

SummaryThe92,94,96,98Mo(t, p) reactions have been studied atE t=12 MeV using a multichannel magnetic spectrograph. Energy levels have been obtained up to excitation energies 4.0, 3.6, 3.3 and 2.8 MeV in94Mo,96Mo,98Mo, and100Mo, respectively, and the angular distributions have been measured for the levels over an angular range 5° to 87.5°. The data have been analysed in terms of the DWBA method andLn andJπ values are derived. Absolute cross-sections have been measured for all the reactions. A comparison of these results with earlier data has been made and although many of the previous assignments have been confirmed, ambiguities in the case of some spin assignments have been removed and several new assignments have also been made. The increasingL=0 strength to excited states in the heavier Mo isotopes suggests the onset of a nuclear-phase transition.RiassuntoLe reazioni92,94,96,98Mo(t, p) sono state studiate aEt=12 MeV usando uno spettrografo magnetico multicanale. I livelli di energia sono stati ottenuti fino ad energie di eccitazione di 4.0, 3.6, 3.3 e 2.8 MeV per, rispettivamente,94Mo,96Mo,98Mo e100Mo e sono state misurate le distribuzioni angolari per i livelli entro un’intervallo angolare tra 5° e 87.5°. I dati sono stati analizzati secondo il metodo DWBA e si deducono i valori diLn eJπ. Sono state misurate le sezioni d’urto assolute per tutte le reazioni. È stato fatto un paragone tra questi risultati e i dati precedenti e, sebbene siano state confermate molte delle precedenti attribuzioni, sono state eliminate le ambiguità nel caso di alcune diverse nuove attribuzioni. L’aumento della forza perL=0 per stati eccitati negli isotopi piú pesanti del Mo suggerisce l’inizio di una transizione di fase nucleare.РеэюмеИсследуются реакции92,94,96,98Мо (t, р) при Еt = 12МзВ, испольэуя многоканальный магнитный спектрограф. Получены уровни знергий вплоть до знергий воэбуждения 4.0; 3.6; 3.3 и 2.8 МзВ в94Мо,96Мо,98Мо и100Мо, соогветственно. Иэмерены угловые распределения для зтих уровней в области углов от 5° до 87.5°. Полученные данные аналиэируются в рамках DWВА метода и определяются эначения Ln иJπ. Для всех реакций иэмерены абсолютные поперечные сечения. Проводится сравнение полученных реэультатов с опубликованными данными. Хотя многие предыдушие реэультаты подтверждаются, удалось устранить неоределенность в определении некоторых спиновых характеристик и получен ряд новых величин. Воэрастание интенсивности L = 0 в воэбужденных состояниях в более тяжелых иэотопах Мо подтверждает начало ядерного фаэового перехода.

A study of the (τ, α) reaction on 50Cr

Abstract The 50 Cr(τ, α) 49 Cr reaction has been studied at E τ = 16.0 MeV using the Tandem Van de Graaff accelerator and the multichannel magnetic spectrograph of the Nuclear Physics Laboratory, Oxford. Twenty-nine levels up to an excitation of ≈ 6.8 MeV have been observed, including a few analogues. The angular distributions have been analyzed in terms of the DWBA theory of direct reaction. The J π limits and spectroscopic factors are obtained for various levels.

Bound levels in29P populated in the28Si(3He, d) reaction

SummaryMeasurements are carried out on the angular distribution of deuterons from the28Si(3He, d) reaction at 17 MeV leading to the bound levels in29P. Analyses of the data show that these are fairly well given by the single-step DWBA mechanism and that the importance of a two-step process is negligible.RiassuntoSi ottengono misure della distribuzione angolare dei deuteroni dalla reazione28Si(3He, d) a 17 MeV che porta ai livelli legati in29P. L’analisi dei dati mostra che questi sono forniti abbastanza bene dal meccanismo DWBA ad un solo passaggio e il processo a due passaggi è trascurabile.