Acceleration mass spectrometer of the Budker Institute of Nuclear Physics for biomedical applications

An accelerator mass spectrometer (AMS) made at the Budker Institute of Nuclear Physics (BINP), Siberian Branch, Russian Academy of Sciences, is installed in the Geochronology of the Cenozoic Era Center for Collective Use for the carbon 14 dating of samples. Distinctive features of the BINP AMS include the use of a middle energy separator of ion beams, magnesium vapor target as a stripping target, and a time-of-flight telescope with thin films for accurate ion selection. Results of experiments measuring the radiocarbon concentration in test samples with radiocarbon labels for biomedical applications are presented.     

Superconducting Multipole Wigglers for Generating Synchrotron Radiation at the Budker Institute of Nuclear Physics

Physics of Particles and Nuclei Letters - Superconducting multipole insertion devices (wigglers and undulators) used to generate synchrotron radiation significantly increase the photon flux,...     

Project of a Super Charm-Tau factory at the Budker Institute of Nuclear Physics in Novosibirsk

A project of a Super Charm-Tau factory is being developed at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) in Novosibirsk. The electron-positron collider to be employed will operate at c.m. energies in the range between 2 and 5 GeV at an unprecedentedly high luminosity of 10³⁵ cm^?2 s^?1 with a longitudinal electron polarization at the beam-interaction point. The main objective of experiments at the Super Charm-Tau factory is to study processes involving the production and properties of charmed quarks and tau leptons. A high luminosity of this setup will make it possible to obtain a statistical data sample that will be three to four orders of magnitude vaster than that from any other experiment performed thus far. Experiments at this setup are assumed to be sensitive to effects of new physics beyond the Standard Model. Investigations to be carried out at the Super-Charm-Tau factory will supplement future experiments at Super-B factories under construction in Italy and in Japan.     

On the Efficiency of Particle Injection into the Damping Ring of the Budker Institute of Nuclear Physics

The efficiency of injection from a linear accelerator into the damping ring of the BINP injection complex has been experimentally studied. The estimations of the injection efficiency are in good agreement with the experimental results. Our method of increasing the capture efficiency can enhance the productivity of the injection complex by a factor of 1.5–2.     

Memorable Years for Synchrotron Radiation at the Institute of Nuclear Physics in Novosibirsk

In the early 1970s, the Institute of Nuclear Physics (INP) in Novosibirsk was a unique place in the world of accelerator physics. There were three operational electron-positron storage rings at the institution. All together, they covered beam operational energies from 200 MeV up to 2.2 GeV. It was not a big surprise for the developers of these state-of-the-art machines when the first users of synchrotron radiation showed up at the doorsteps of the Institute of Nuclear Physics, eager to take advantage of such unique radiation sources. And how very unique they were! Compared with several already relatively well-established operational synchrotrons around the world, such as DESY in Hamburg, NINA in Darsbury, and three synchrotrons in the Soviet Union—one at the Physical Institute in Pakhra, another at the Tomsk Polytechnical Institute, and a third at the Erevan Physical Institute—the storage ring sources provided much more stable and brighter radiation beams. Several storage rings built at that time in locations such as Japan, the US, and France were also on the verge of becoming available for synchrotron radiation users.     

The Joint Institute for Nuclear Research in Experimental Physics of Elementary Particles

The year 2016 marks the 60th anniversary of the Joint Institute for Nuclear Research (JINR) in Dubna, an international intergovernmental organization for basic research in the fields of elementary particles, atomic nuclei, and condensed matter. Highly productive advances over this long road clearly show that the international basis and diversity of research guarantees successful development (and maintenance) of fundamental science. This is especially important for experimental research. In this review, the most significant achievements are briefly described with an attempt to look into the future (seven to ten years ahead) and show the role of JINR in solution of highly important problems in elementary particle physics, which is a fundamental field of modern natural sciences. This glimpse of the future is full of justified optimism.     

Evolution of nuclear spectroscopy at Saha Institute of Nuclear Physics

Experimental studies of nuclear excitations have been an important subject from the earliest days when the institute was established. The construction of 4 MeV proton cyclotron was mainly aimed to achieve this goal. Early experiments in nuclear spectroscopy were done with radioactive nuclei with the help of beta and gamma ray spectrometers. Small NaI(Tl) detectors were used for gamma-gamma coincidence, angular correlation and life time measurements. The excited states nuclear magnetic moments were measured in perturbed gamma-gamma angular correlation experiments. A high transmission magnetic beta ray spectrometer was used to measure internal conversion coefficients and beta-gamma coincidence studies. A large number of significant contributions were made during 1950–59 using these facilities. Proton beam in the cyclotron was made available in the late 1950’s and together with 14 MeV neutrons obtained from a C-W generator a large number of short-lived nuclei were investigated during 1960’s and 1970’s. The introduction of high resolution Ge gamma detectors and the improved electronics helped to extend the spectroscopic work which include on-line (p ₇ p′γ) and (p ₇ nγ) reaction studies. Nuclear spectroscopic studies entered a new phase in the 1980’s with the availability of 40–80 MeV alpha beam from the variable energy cyclotron at VECC, Calcutta. A number of experimental groups were formed in the institute to study nuclear level schemes with (α ₇ xnγ) reactions. Initially only two unsuppressed Ge detectors were used for coincidence studies. Later in 1989 five Ge detectors with a large six segmented NaI(Tl) multiplicitysum detector system were successfully used to select various channels in (α ₇ xnγ) reactions. From 1990 to date a variety of medium energy heavy ions were made available from the BARC-TIFR Pelletron and the Nuclear Science Centre Pelletron. The state of the art gamma detector arrays in these centres enabled the Saha Institute groups to undertake more sophisticated experiments. Front line nuclear spectroscopy works are now being done and new informations are obtained for a large number of nuclei over a wide mass range. Currently Saha Institute is building a multi-element gamma heavy ion neutron array detector (MEGHNAD), which will have six high efficiency clover Ge detector together with charged particle ball and other accessories. The system is expected to be usable in 2002 and will be used in experiments using high energy heavy ions from VECC.     

X-ray fluorescence activities at Saha Institute of Nuclear Physics,India

This paper covers different aspects related to X-ray fluorescence activities at Saha Institute of Nuclear Physics, Kolkata, India. In its first part, experiments on basic physical problems are illustrated and in the second part, some applications related to X-ray fluorescence are discussed.     

Dynamics of the pulsed free-electron laser

Calculations of coherent picosecond pulse propagation in the free-electron laser are presented, based on a theory directly coupling the Maxwell and single-particle equations. Good agreement is obtained with data of the Stanford experiment, such as the power-tuning curve and the electron energy distribution.     

A free-electron laser pumped by the soliton laser

We propose a scheme for building a free-electron laser in the soft X-ray region pumped by the soliton laser. Making use of soliton laser wave evolution shape and single-pass small signal analysis, we find that this laser has two special advantages over the previous electromagnetic wave undulator free-electron lasers. One is a very small mass-shift effect because of the special characteristics of soliton laser; the other is that it has an additional frequency tuning effect based on the conventional free-electron laser's tunability. We also obtain the small signal gain and present some discussion.     

High-gain small-signal modes of the free-electron laser

The small-signal regime of the free-electron laser is analyzed for single-frequency, uniform-wiggler operation, taking diffraction into account. Exponentially growing modes are found with profiles independent of the longitudinal coordinate. Maximum gain occurs for a positive value of the energy detuning, though the gain on resonance is nearly maximal. If the current transverse distribution is uniform and sharp-edged, analytic solutions are obtained in terms of Bessel and Hankel functions with complex arguments. Positive energy detuning broadens the laser modes, while negative detuning concentrates them within the electron beam.     

To the theory of a free-electron laser

The interaction of an electron beam, moving inside a magnetic lattice, with an electromagnetic wave is considered. It is shown that under certain conditions generation (amplification) of coherent electromagnetic radiation occurs. The gain is calculated.     

深度学习在核物理中的应用

深度学习是目前最好的模式识别工具,预期会在核物理领域帮助科学家从大量复杂数据中寻找与某些物理最相关的特征。本文综述了深度学习技术的分类,不同数据结构对应的最优神经网络架构,黑盒模型的可解释性与预测结果的不确定性。介绍了深度学习在核物质状态方程、核结构、原子核质量、衰变与裂变方面的应用,并展示如何训练神经网络预测原子核质量。结果发现使用实验数据训练的神经网络模型对未参与训练的实验数据拥有良好的预测能力。基于已有的实验数据外推,神经网络对丰中子的轻原子核质量预测结果与宏观微观液滴模型有较大偏离。此区域可能存在未被宏观微观液滴模型包含的新物理,需要进一步的实验数据验证。     

Classical theory of a free-electron laser

We present a completely classical analysis of the small-signal regime of a free-electron laser. It is explicitly shown that the amplification is due to stimulated scattering produced by a bunching of the electron distribution.     

Three-dimensional Wigner-function description of the quantum free-electron laser

A free-electron laser (FEL) operating in the quantum regime can provide a compact and monochromatic x-ray source. Here we present the complete quantum model for a FEL with a laser wiggler in three spatial dimensions, based on a discrete Wigner-function formalism taking into account the longitudinal momentum quantization. The model describes the complete spatial and temporal evolution of the electron and radiation beams, including diffraction, propagation, laser wiggler profile and emittance effects. The transverse motion is described in a suitable classical limit, since the typical beam emittance values are much larger than the Compton wavelength quantum limit. In this approximation we derive an equation for the Wigner function which reduces to the three-dimensional Vlasov equation in the complete classical limit. Preliminary numerical results are presented together with parameters for a possible experiment.