NRV

Motivation
Main ideas and principal scheme
Operation system and coding
Main possibilities and main menu
References
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Abstract

The NRV is an open and permanently extended global system of management and graphical representation of nuclear data and video-graphic computer simulation of low energy nuclear dynamics. It consists of a complete and renewed nuclear database and well known theoretical models of low energy nuclear reactions altogether forming the "low energy nuclear knowledge base". The NRV solves two main problems.
(1) Fast and visualized obtaining and processing experimental data on nuclear structure and nuclear reactions.
(2) Possibility for any inexperienced user to analyze experimental data within reliable and commonly used models of nuclear dynamics.

The system is based on the realization of the following principal things

  • The net and code compatibility with the main existing nuclear databases.
  • Maximal simplicity in handling: extended menu, friendly graphical interface, hypertext description of the models, and so on.
  • Maximal visualization of input data, dynamics of studied processes and final results by means of real 3-dimensional images, plots, tables and formulas, and a 3-dimensional animation.
All the codes are composed first as the real Windows applications working under Windows 95/NT. After that, one by one they are transformed to the Web-applications accessible with the standard browsers (HTML, PHP, CGI, Java). The process is rather slow but it nevertheless goes on.

Motivation

There are two problems encountered by every physicist (both an experimentalist and theorist) in his everyday work on processing experimental data or preparing new experiments: (1) search for available experimental data on nuclear properties and nuclear reactions and treatment of these data, (2) analysis of the processes under study within reliable theoretical models of nuclear dynamics. The first problem can be solved at best as follows. A user looks for appropriate nuclear database, finds required nucleus, and writes out the value of parameter he needs. There are several well-known and permanently renewed nuclear databases (see [1-8] and other references/links therein). However, most of these databases are formed like ordinary text tables (easily accessible and visible via Internet) or like downloaded files. So, if you want to obtain some systematics over a group of nuclei (for example, separation energy of two neutrons from the isotopes of a given element) and view a plot, you have to write out several tens of numbers, make some calculations (even rather simple), obtain a table, and use some graphic package to draw a plot.

More complicated problems appear when we solve the second task - analysis of experimental data within theoretical models of nuclear dynamics. There are very effective and reliable theoretical approaches to description of low energy nuclear reactions and nuclear structure: optical model of elastic scattering, distorted wave Born approximation, channel coupling approach, statistical model of nuclear decays and fission, shell model, and many others. However, the corresponding computer codes are written, as a rule, in Fortran. They have a long lists of instructions on preparation of input data and make the calculations "blindly" without a possibility of watching the dynamics of the process under study to understand it quite clear. The final results are presented in the tabular form demanding their subsequent processing with some graphical tools. Finally, these codes are very difficult in management and are commonly used either by the authors or by trained specialists occasionally specially invited. Note that even for theorists, who understand the models themselves well, it is not so easy to use somebody else's codes for overall analysis of the investigated process. This situation leads to artificial specialization of physicists who are experienced only in one model, and also to a loss of unity in performing and treating the physical experiments, all this requiring additional time and expenses. Creation of the effective "low energy nuclear knowledge base" could help us solve these problems.


Main ideas and principal scheme

These well-established and commonly used models of low energy nuclear dynamics (such as the optical model, DWBA for transfer and breakup reactions, channel coupling method, transport equations of the deep inelastic process and fusion, statistical model of decay of hot nuclei, few body molecular dynamics, shell model, liquid drop model, and many others) have to be arranged in the way so that to be accessible and easily used by any inexperienced (in sense of programming) scientist working in the field of low energy nuclear physics. The total set of the intersected algorithms of nuclear dynamics must lean on the experimental nuclear database and be controlled by a common multi-paged interface altogether forming what is usually called "knowledge base". A principal scheme of this nuclear "knowledge base" is shown in Fig.1.
NRV
Fig. 1. Principal scheme of the low energy nuclear knowledge base NRV

Creation of the NRV system is based on realization of the following principal points.

  • Net and program compatibility with existing nuclear databases [1-2]. It provides us with renewed and permanently extended experimental information on basic nuclear properties such as nuclear masses, modes of decay, half-lives, excited states, and so on.
  • Maximal simplicity in handling. This is assured by the widely branched menu, visual graphic representation of all information, hypertext descriptions, references, and HELP system.
  • Maximal visualization of all input data, dynamics of the investigated process, and final results by means of real images, plots, tables, formulas, and 3-dimensional animation.
  • All software are operated under Windows 95/NT. This solves the problem of compatibility of the NRV system with any peripheral devices and with such commonly used software as Corel Draw, Origin, Microsoft Word, and other Windows applications.
  • Accessibility of the "knowledge base" via standard local and global computer nets.


Operation system and coding

A choice of operation system is very important for such a software like the NRV. Unfortunately there is no a unified operation system used by all physicists. Some people work with UNIX, others prefer Windows. We chose the latter because, as it seems to us, there is more advanced and faster developing software created just under Windows. This operation system is supported now not only by IBM but also by Macintosh personal computers.

Using C++ as a main coding language (Borland C++ compiler under Windows) we obtain a powerful tool for building our main classes of graphical support (including a 3-dimentional one), numerous interface dialogs, handling the database, and all the algorithms of nuclear dynamics. The BDE_IDAPI SDK and IDAPI functions are used in the work with our database. The DBF representation of the experimental data on nuclear properties is sufficiently convenient to work with them and can be easily changed if some other format would be found to be more appropriate for a net version of the NRV. At present all experimental data are divided in several DBF-tables (masses, modes of decay, energy levels, and so on) which can be downloaded separately in case of need. As already mentioned, these data can be renewed and edited directly using the basic external databases or some other sources of information.

All the algorithms of nuclear dynamics (see below) are written with C++ and formed as real Windows applications, i.e., they can start and operate independently, but they all rest on the same database and have a common starting interface. It means that analyzing, for example, collision of nuclei A and B within different models (elastic scattering, fusion, transfer reaction,...) one automatically uses the same interaction parameters and other properties of both nuclei in the entrance channel.

We found that the simplest codes of processing nuclear data and some nuclear models can be formed as Java applets and, therefore, be directly accessible through the net with any computer (irrespective of operation system) having a Web-browser supported Java codes, for example, Internet Explorer 4, Netscape Navigator 4, or higher. Advantages of the JavaScript technology in forming and managing nuclear database can be viewed in the Lund Nuclear Data WWW Service as an example [7]. Resemblance of the object oriented languages C++ and Java allows us, in principle, to rewrite most of the simplest Windows application in the form of full-fledged Java applets. Of course, the available Java compiler (Java Developers Kit) is not so effective and convenient yet as C++ compilers. However, very fast evolution of the Java technology can bring us in nearest future to quite a new situation when the Java language will be used not only for the Web purposes but also for coding very complicated algorithms.


Main possibilities and main menu

The main menu of the NRV consists of the following hierarchic items leading to the basic nuclear models and to processing nuclear data. Today some of the models of low energy nuclear dynamics (see below) operate in full capacity, and others are under construction.

Quit

 

 

NUCLEI

Nuclear Map

 Available Information
 Systematics
 Decay chains

NUCLEAR MODELS

 Shell Model
 Liquid Drop Model

 

DECAYS

 Alpha-decay
 Beta-decay
 Fission
 Decay of Hot Nuclei

 

NUCLEAR REACTIONS

Elastic Scattering

Classical Model

Semiclassical Model

Optical Model

Inelastic Scattering

Coulomb Excitation

Direct Process (DWBA)

Deep Inelastic Collisions

Fusion

Classical Model

Langevin Equations

Empirical Models

Channel Coupling

Driving Potentials

Transfer Reactions

3-body Classical Model

Direct Process (DWBA)

Multi-nucleon Transfer

Breakup Reactions

3-body Classical Model

Direct Process (DWBA)

Sequential Decay

Fragmentation

Pre-Equilibrium Particles

Classical Models

Fermi-jet Model

Moving Sources

Kinematics

2-body Kinematics

3-body Kinematics

Help

 

 

The graphical interface of the main menu (see Win-NRV) is a common "entrance point" to the NRV. In spite of the fact that all the models listed above are prepared as self-dependent Windows applications and can be started separately, one has to pass this "entrance point" if you want to analyze some process of collision within different approaches keeping the same values of all common parameters of colliding nuclei. It means that the "Input Dialogs" of all the models look very similar to each other and operate with the same set of accumulated variants of different reactions studied by a user of the NRV. Any variant can be changed, deleted, or added to the database only within the main program of the NRV, which, thus, performs the duties of a dispatcher. There are many common input parameters for different reaction channels of the nucleus-nucleus collision: projectile-target interaction, energy of collision, some properties of colliding nuclei. Thus, it is quite reasonable to have a common DBF table, every line of which completely defines one of the studied collision processes, i.e., all the parameters of the entrance channel and different exit channels.
Detailed description of the NRV and some of the models can be found in [9].

References

[1] Atomic Mass Data Center (Orsay), G.Audi, A.H.Wapstra, Nucl.Phys., A595 (1995), 409; ibid. A624 (1997), 1.
[2] National Nuclear Data Center, Brookhaven National Laboratory, T.W.Burrows.
[3] Nuclear Data Services, Nuclear Energy Agency, France.
[4] IAEA's Nuclear Data Centre.
[5] Center for Photonuclear Experimental Data, Moscow State University, V.V.Varlamov.
[6] Nuclear Data Center, Japan Atomic Energy Research Institute.
[7] Lund Nuclear Data WWW Service, P.Ekstrom.
[8] Isotopes Project, LBNL.
[9] V.Zagrebaev, A.Kozhin, Nuclear Reactions Video (knowledge base on low energy nuclear physics), JINR Report No. E10-99-151, Dubna, 1999 (PDF is available).


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