Production scheme for diagnostic-therapeutic radioisotopes by accelerator neutrons

Interest has been growing in the development of medical radioisotopes used for noninvasive nuclear medicine imaging of disease and cancer therapy. Especially the development of an alternative production scheme of ⁹⁹Mo, the mother radioisotope of ^99mTc used for imaging, is required, because the current supply chain of the reactor product ⁹⁹Mo is fragile worldwide. We have proposed a new production scheme of ⁹⁹Mo as well as therapeutic radioisotopes, such as ⁶⁴Cu and ⁶⁷Cu, using accelerator neutrons provided by the ^natC(d,n) reaction. Based on this scheme we have obtained high-quality ^99mTc, ⁶⁴Cu, and ⁶⁷Cu suitable for clinical use by developing both production and separation methods of the radioisotopes. We proposed a new facility to constantly and reliably produce a wide variety of high-quality, carrier-free radioisotopes, including ⁹⁹Mo, with accelerator neutrons. We report on the development of the proposed scheme and future prospects of the facility toward the domestic production of medical radioisotopes.     

Correlations and symmetries in the spectra of light α-cluster systems

The correlated behaviour of the α-cluster bands of ²⁰Ne, ¹⁹F and ¹⁸F is discussed in terms of a U(4|12) superalgebra scheme. Predictions are compared with the spectroscopic information on ²⁰Ne and ¹⁹F, and further data supporting this scheme are presented for ¹⁸F.     

Rotational states in 151Nd populated through thermal neutron capture

The level scheme in the nucleus ¹⁵¹ Nd has been studied following neutron capture by observing the γ-rays and conversion electrons with curved-crystal spectrometers, a Ge(Li) detector and a β-spectrometer. A comprehensive level scheme up to ? 1 MeV was established. It is shown that the present level scheme energies differ from those previously found in a ¹⁵⁰Nd(d, p) reaction study by a systematic shift of 27 keV. The binding energy of the last neutron in ¹⁵¹Nd was deduced. For most levels spin and parity values are proposed and an identification of bands with Nilsson-model configurations is given.     

Spectroscopy of 212Rn

Excited states of ²¹²Rn have been studied using γ-ray and electron spectroscopy following the reactions ²⁰⁸Pb(⁹Be, 5n) and ²⁰⁴Hg(¹³C, 5n). With the exception of the energy of the yrast 8⁺→ 6⁺ transition, the previously proposed level scheme has been verified. New transitions have been placed in the level scheme and new lifetime and g-factor results obtained. The level scheme and electromagnetic properties of selected isomeric states are compared with the results of shell model and semi-empirical shell-model calculations, including coupling to octupole vibrations.     

Level scheme of <Superscript>242</Superscript>Am

Published level scheme of ²⁴²Am includes 39 levels, places 118 transitions out of 246 transitions measured, and has normalized χ² = 6.6, with the individual contribution to the total χ² of each of the 16 transitions with the worst energy placement being > 9. Using the program of construction of the level scheme with the aid of Ritz combinations enabled us to add 35 new levels, place 201 transitions, and construct the final level scheme with χ² = 1.3. No transition energy error in the final scheme differs from the error of the energy difference of levels between which this transition is placed by more than a factor of 3. Published in Russian in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2007, Vol. 71, No. 8, pp. 1225–1232. In memory of Yu. Akovali The article was translated by the author.     

A note on the accuracy of parameterisations of the surface radiative fluxes in clear and cloudy conditions

We present the results of a study to compare the values of the components of the surface radiative balance predicted by the empirical formulae used by Benwellet al.⁽¹⁾ and Burridge and Gadd⁽³⁾ with those obtained from a more accurate radiative scheme. We find that, within the accuracy of the existing climatological data, the solar scheme is suitable for use in a numerical model of the atmosphere.The longwave scheme is inaccurate for such purposes and should therefore be used with caution.     

β+ decay of unstable praseodymium isotopes: 127Pr, 126Pr and the new isotope 125Pr

The β⁺ decay of ^127,126,125Pr was studied for on-line mass-separated sources. The decay scheme of ¹²⁷Pr reported previously was revised from the results of a more-detailed analysis of the experimental data. The ¹²⁵Pr isotope was newly identified with a half-life of 3.3(7) s and its decay scheme is presented. The γ band in ¹²⁶Ce was identified in the decay of ¹²⁶Pr and its properties are compared with the prediction of the interacting boson model 2.     

A new algorithm for one-dimensional problems

A new computation scheme in perturbation theory is developed for one-dimensional nonrelativistic problems with static potentials. If λ is a measure of the strength of the perturbation, after n steps in this scheme, the energy and wave function corrections are known to order λ^2n?1, whereas the same are known only to order λⁿ in the ordinary perturbation expansion.     

Study of a low power dissipation, miniature laser-pumped rubidium frequency standard

This paper studies a miniature low power consumption laser-pumped atom vapour cell clock scheme. Pumping ⁸⁷Rb with a vertical cavity surface emitting laser diode pump and locking the laser frequency on a Doppler-broadened spectral line, it records a 5× 10^-11τ^-1/2 (τ <500~s) frequency stability with a table-top system in a primary experiment. The study reveals that the evaluated scheme is at the level of 2.7 watts power consumption, 90~cm³ volume and 10^-12τ ^-1/2 short-term frequency stability.     

Z′ and the Appelquist–Carrazzone decoupling

We consider the electroweak theory with an additional neutral vector boson Z^′ at one loop. We propose a renormalization scheme which makes the decoupling of heavy Z^′ effects manifest. The proposed scheme justifies the usual procedure of performing fits to the electroweak data by combining the full SM loop corrections to observables with the tree-level corrections due to the extended gauge structure. Using this scheme we discuss in the model with extra an U(1)^′ group factor one-loop results for the ρ parameters defined in several different ways.     

Shell model study of high spin states in theN=50 nucleus93Tc

High spin states in theN=50 nucleus⁹³Tc were reinvestigated by using the reaction⁶⁴Zn (³⁵Cl,4p 2n) at a beam energy of 140 MeV. This was done particularly with a view to observe anyγ rays upto 2.7 MeV which may have been missed in our earlier study where the experimental conditions were set to observeγ rays upto 2 MeV. We found four newγ rays of energy: 2484, 2164, 2130 and 69 keV. We have placed theseγ rays in the level scheme and it now gets extended to 49/2^?. Though there is no substantial change in the level scheme, placing theγ rays in the level scheme has resulted into two important conclusions: (1) We have performed shell model calculations for⁹³Tc nucleus within a model space which encompasses an enlarged proton configuration and allows for the excitation of the neutron across theN=50 core. The excitation of a single neutron across theN=50 core satisfactorily explains the new level scheme. (2) The energy of the 17/2^? isomeric state is now unambiguously placed at 2185 keV.     

Atomic mass of145Eu derived from relative PK-ratios

The level scheme of⁹³Ru has been studied in⁴⁰Ca induced reactions on Ni and Fe targets. Two new levels feeding the known 17/2⁺ state have been established: an isomeric level (T_1/2=2.6 us) at 2081.5 keV with J=21/2⁺ and a level at 2103 keV, presumably a 17/2^? state. The B(E2; 21/2⁺→17/2⁺) value and the level scheme are compared to shell model predictions.     

激光准直Cr原子束的实验研究

利用多普勒原理对Cr原子束进行横向准直.应用激光感生荧光技术稳定激光器的频率，把激光器的中心频率稳定在偏离Cr原子共振中心频率-5±0.26MHz的位置.根据理论计算出准直激光束的最小尺寸为13.7mm.根据实验数据选择合适的参数，实现利用多普勒原理横向准直Cr原子束，使原子束的横向分布缩小到原来的1/3. 关键词： 激光准直 激光感生荧光稳频 多普勒冷却     

The decay of123Xe

The decay scheme of 2.1 h¹²³Xe has been investigated using isotopically separated samples produced by the ISOLDE facility at CERN. A total number of 108 γ-transitions has been observed in this decay, 103 of them have been placed in a level scheme involving 28 excited states in¹²³I. This level scheme is mainly based on the results of γγ-coincidence experiments with two Ge(Li) detectors.     

Koinzidenzmessungen am Ta183→W183-Zerfall mit Hilfe eines eisenfreien Orangen-Beta-Spektrometers

The decay of Ta¹⁸³ has been studied using an iron-free orange-type beta-ray spectrometer. Beta-gamma coincidence measurements confirm the proposed level scheme of W¹⁸³. The recently discovered 313.28 keV transition has been inserted into the level scheme and a new single particle state 9/2⁺ [624] at 622.7 keV is proposed. The isomeric level at 309.4 keV is shown to have spin and parity 11/2⁺.     

Order α 2 s massive quark contribution to the vacuum polarization of massles quarks

We calculate to order α ₂ ^s in the QCD coupling the effect of massive quarks on the vacuum polarization of massless quarks both in a momentum subtraction scheme and in the (modified) minimal subtraction scheme. We also illustrate how decoupling of heavy quarks takes place in this context in the minimal subtraction scheme.     

Reciprocal space-time and momentum-space singularities in the narrow resonance approximation

A general scheme is proposed which makes explicit the relationship between the singularities of off-shell amplitudes in position-space and momentum-space in the narrow resonnace approximation. In some ways this may be viewed as a duality scheme for amplitudes involving external quarks, in which narrow resonances in certain channels build the Fourier transform of power singularities in x² (x^μ being a position vector). This scheme is made precise by dual string off-shell amplitudes. As well as highlighting possible connections between the general dual framework and the structure of confined field theories we are able to pinpoint certain grave shortcomings of present dual models.     

Nuclear structure of194Pt

The decay of¹⁹⁴Ir has been thoroughly studied resulting in the construction of a decay scheme consisting of 26 excited states and 69 transitions. Nine new levels and 29 new transitions were added to the previously known scheme. Of these, levels at 1,893.6 and 2,053.0 keV as well as 9γ-ray transitions are new to the¹⁹⁴Pt level scheme. Preciseγ-ray energy and intensity measurements as well as quantitative coincidence measurements were performed, and the internal conversion spectrum was investigated with a Si(Li) detector. Directional correlation measurements were performed for selected cascades with the major result being the unique assignment of 0⁺ to the new level at 1,893.6 keV. The structure was interpreted within the framework of the PPQ model as well as the effective-core picture including nuclear triaxiality.     

Energy levels of92Nb from 92Zr(p,nγ)92Nb

The energy levels of⁹²Nb were studied by means of the⁹²Zr(p, nγ) reaction. The deexcitation γ-rays were observed with a high-resolution Ge(Li) detector in the proton energy range 3.00–4.80 MeV in steps of about 25 keV. Many new excited states of ⁹²Nb were populated by this reaction. Excitation energies up to 1.77 MeV were determined with high precision, and a level scheme of ⁹²Nb is proposed. From a Hauser-Feshbach analysis, the γ-decay scheme and other information, the spin-parities of many levels were assigned.