Tools for data analysis and MC simulations
in exotic nuclear experiments. SIMONE project.
http://aculina.jinr.ru/simone.htm
R.S. Slepnev1, V. Chudoba1,2, P. Papka3, P.G. Sharov1, B. Hnatio4, S. Baraeva1,
P. Jaluvkova1,2, A.G. Knyazev1
1 -- Joint Institute for Nuclear Research (JINR), Dubna, Russia
2 -- Institute of Physics, University of Silesia in Opava, Opava, Czech Republic
3 -- Stellenbosch University, Stellenbosch, Western Cape, South Africa
4 -- University of science and tehcnology, Krakov, Poland
Physics of Exotic Nuclei
light nuclei (A<50)
exotic structure, rare decay modes
typical RIB's energies < 100 MeV/A
a few detector types to disposal
Motivation
There are many various experiments performed, but most of them are based on the same
pattern. It means that you have some beam, fixed target and you need to detect reaction
and decays products by some complex detector arrangement which subsequently result in
sophisticated data analysis.
Available tools designated for our field are either too specialized (such as SRIM, LISE++)
or provide fundamental methods only and are intended for further developments of specific
applications.
Of course, you can develop your own software solution for each experiment, but much
more efficient is to use some general-purpose tool that can be easily adopted by the user
without necessarily modifying the source.
We can find many common features of our experimental studies and both, the planning of
an experiment and data processing consist of specific steps which are often standard
repeated procedures. For example description of particles and their kinematics, detectors,
particle tracking and so on
many tasks can be generalized (simulations, some auxiliary methods for data analysis
The main motivation of the SIMONE project is to save human power and time, and
standardize the common procedures to reduce the possibility of bias and errors inherent to
computer programming.
General scheme
based on ROOT Data Analysis Framework
optional use of alternative methods based on GEANT4,
SRIM, ...
libraries usable in ROOT CINT
architecture is reflecting real course of actions
as general as possible
no need for programming for plenty of tasks
General scheme: Simulations
all essential actions can be fully formalized and
automatic user input
theoretical input
experimental setup description
SIMONE provides
primary event generation
detectors and materials handling
particle tracking
TTree's on output
simulated data of the same structure as
experimental
General scheme: Experimental branch
data analysis
unique for each experimental setup
often plagued with unforeseen situations
process of data analysis is identical for both experimental and simulated data
Functionality: Kinematic calculator
Elab [MeV/A]
2 cornerstones:
Calculation of kinematics can be solved either analytically or
using MC method. However, the employment of the latter
option is more convenient when one deals with
multiparameter tasks. MC provides sufficient results and is
much more efficient with respect to both difficulty and time
requirements.
The kinematical calculator itself consists of two major
components: class serving for description of arbitrary particle
and class modelling nuclear reaction. Class particle provide a
set of methods to treat any particle properties, such as
kinematical characteristics, atomic mass, charge and so on.
Particles may be collected in class Reaction which is
p(6Li,n)6Be
intended to manage particles and relativistic kinematical
6Be 3-body decay
relations between them. Class Reaction distinguishes
particles on input and output of the reaction and amongst
others provide methods to transform particles into different
coordinate systems, methods for generation of binary
reactions, 2- and 3-body decays with uniform distribution in
space volume are provided. We provide also interface for
p(18Ne,d)17Ne
input of whatever external distributions.
17Ne 3-body decay
lab [degrees]
The kinematic methods can be used either on stage of
simulation or can be employed for particles properties
reconstruction during the experimental data analysis.
Functionality: Geometry
some of the most common
detectors implemented
concept of parameterized detector classes
whole detector is represented by one entity
detector objects serve as data containers
build geometry by assigning dimensions,
materials, and position together with
orientation in space
detector setup visualisation
Functionality: Tracking
All SIMONE elements of virtual setup possess
methods to handle particle passing through it.
When a particle enters detector, the interaction
of the radiation with the detectors materials are
taken into consideration and the momentum of
the particle is altered.
Currently, only electromagnetic ionization of
material by particle passing through is taken
into account because it is major source of
energy loss in the typical range of low energy
nuclear physics.
Afterwards, energy deposits are written into
detector objects.
ΔE [MeV]
We may use two alternative algorithms for
tracking and energy losses. They are either
ROOT TGeo + various E-losses methods or
optionally some external GENAT4 routines.
E [MeV]
Functionality: Tools for analysis
too complex for just “click and wait” approach
currently under development
channels
channels
ΔE [MeV]
common steps are found and standardised
detector calibrations
auxiliary functions for particle identification
RIB's diagnostics, beam projection on arbitrary
plane
ascertainment of hits in detectors
particle trajectory reconstruction from trace in
telescope
particle energy reconstruction and handling
with dead layers
E [MeV]
E [MeV]
Functionality: Control and handling
In order to make the SIMONE package as user
friendly as possible and to ensure high level of
generality, two different ways of object
construction for the most important classes are
given. The classical option is to create an object
and then adjust its properties using standard
Setter methods. A more convenient way is to
set all parameters at once using externally
stored configuration files which containes
information on objects in a structured but easy
editable and human readable format.
The main advantages of these config files is
that they provide intuitive interface between our
libraries and external applications, especially for
GUI. GUI was designed to help with setting up
entire environment for simulation in a
transparent and easy way. The introducing of
GUI is a major step towards user friendliness. It
also helps to have all parameters visible and
editable in one place.
Summary
SIMONE is intended for the low-energy nuclear physics community
development of special tools started in an international collaboration
many tasks isolated and routinized
early version released
Plans for future
more development and validation
diversification of calculation methods
handling of ion optics
testing on multiple platforms
FLNR
JINR
Silesian
University
iThemba LABS
AGH Cracow
Thank you for attention