Author Topic: RADlab is Virtual Radiation Detection and Measurement Laboratory Software  (Read 1034 times)

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RADlab is Virtual Radiation Detection and Measurement Laboratory Software - a model of a basic Radiation Detection Laboratory


 Radiation detection and measurement education is necessary for a wide variety of people, such as Nuclear Engineering students, radiation workers, radiotherpahy and others working with radiation. The equipments and laboratory setup needed for delivering this type of education are expensive and difficult to assemble due to the large variety of the type of experiments that are desirable to cover. For a basic radiation detection and measurement laboratory education, one needs to have gamma, beta, alpha and neutron sources, at least one detector to detect each type of radiation and other supplemental nuclear instrumentation to perform experiments. Although the radiation exposure due to these radioactive sources in an education laboratory is low, shielding and a private secured place is needed. Nearly two hundred thousand dollars is needed to construct such a basic laboratory described as above. In order to overcome these difficulties, a model of a basic Radiation Detection Laboratory has been created to provide a virtual environment for designing and simulating such experiments. This software, which is a GPL licensed, open source, free software, is an easy to use solution for Radiation Detection and Measurement education. Project team : Dagistan Sahin, Muzaffer Sena Sahin, Korcan Kayrin.

 Radiation can be electromagnetic radiation such as gamma and X-rays, or particle radiation such as beta, positron, neutron or heavy charged particle, such as alpha and ions. Heavy charged particles mainly interact with matter due to Coulomb forces. These particles have a very short range in matter. Beta electrons and positrons also have short ranges compared to that of neutrons or gammas. However, neutrons and gammas are neutral particles, and have longer ranges of interaction through matter. This study considers only neutron and gamma interactions with matter.

 There is a lot of work done to simulate these types of experiments using Monte Carlo methods. However, most of the avaliable codes are for experienced users and require long learning curves.  Furthermore, these specific nuclear codes used in these simulations are difficult to setup and edit without deep knowledge about radiation physics and an understanding of the codes. To achieve these difficulties experienced by the end user, an extendible, flexible and easy to use environment is created using a high level language JAVATM. A full analog Monte Carlo model is implemented for radiation sources, detectors and intervening materials such as shielding and collimators. The necessary nuclear instrumentation for experiments are also modeled both graphically and numerically to maintain a consistent and real-life feeling virtual environment. The analog Monte Carlo simulation for these detectors  uses available cross-section data libraries [1]. Gamma cross-section data from XCOM [2] , and neutron cross section data from ENDF [3] were used in RADlab. Beta and alpha interaction is implemented using stopping power data from SRIM software [4] and NIST database [5]. Available gamma detectors in the RADlab software are CdZnTe, NaI(Tl)3x3, NaI(Tl)5x5, NaI(Tl)7x7, NaI(Tl)2x2, NaI(Tl)2x2 Well Type, BGO, HPGe, Geiger Muller. Neutron detectors are BF3 1x7, BF3 3x7. Beta-Pips and Alpha-Pips detectors are modeled as beta and alpha detectors, respectively. The environment, in which the experiments are carried on, can be set to air, water or vacuum. For the environments, again the cross-section data from the mentioned databases are used.

  Moreover one needs some shielding material to measure its properties, such as the attenuation coefficient. An Aluminum shield is modeled as an example for this purpose. A useful collimator is modeled made out of pure lead . The basic nuclear spectroscopy instruments are also modeled in RADlab. These are high voltage supplies for the detectors, Preamplifier and Amplifier for signal filtering, Multi Channel Analyzer (MCA) and Oscilloscope to visualize the signals. Additionally, instruments such as Coincidence Unit, Delay Amplifier, Single Channel Analyzer (SCA), Random Pulse Generator and Counter are also modeled.  Some of the most popular radioactive sources are modeled using nuclear data from Lund/LBNL database [6].All of the sources are assumed to be isotropic point sources. The gamma sources 133Ba, 60Co, 137Cs, 22Na and a mixed source are available in the program. Two neutron sources modeled as Americium-Berillium and natural 252Cf. Alpha sources avaliable in RADlab are 241Am, 230Th and 148Gd. and beta sources are 137Cs and 204Tl.

 Experiment Simulation Model
 The program gives the flexibility to create experiments by choosing from variety of sources, detectors and instruments, using a simple experiment creation wizard. Once the user constructs the experiment, the environment in which the experiment would be performed can be selected, and changed during the experiments. A cool feature is to set the environment to air, water or vacuum. 

 After that the user starts an experiment, the analog Monte Carlo engine in RADlab starts the simulation by tracking the sources first.  RADlab uses Javalution api to enhance computation by using parallel computing. For every ten milliseconds, the sources in the environment decay via forced decay. The radioactive particles generated from the sources initially penetrate to the corresponding environment isotropically. While the particles traveling and interacting with the environment, the program checks whether they interact with a detector, material, shield or collimator. When a particle interacts with a detector and deposits some amount of energy, the detector generates a signal on its output. Then this signal is transferred to the instrument connected to the detector. When an instrument receives a signal it processes the signal and transmits to its output.  Therefore, the experiments are quite realistic in terms of random nature of radiation and the interactions with matter. Hence the radioactive sources decay randomly based on their decay constant, sum and escape peaks are generated in the spectrum.

 The working principles of the nuclear instruments are modeled so that they behave similiar to the instruments found in a real radiation detection and measurement laboratory. When the final instrument is a MCA or Oscilloscope, user sees the output. Furthermore, the program can draw the particle paths while the simulation is running to give more visual inside of particle interactions. This feature is especially useful for teaching purposes.

Four type of experiment can be simulated using Radlab. These are gamma experiments. neutron experiments, alpha and beta experiments. 

  • Radiation Detection Experiments
  • Gamma, beta, alpha and neutron sources
  • Coincidence Experiment
  • NIM module and instrumentation
  • Easy setup
  • Radioactive isotope decay
  • Gamma spectroscopy
  • Charged particle spectroscopy
  • Neutron detection
  • Exposure and shielding experiments