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Description
Linear accelerators can be used for various applications including radiotherapy, cargo inspection, industrial radiography, research etc. In this work the X-ray collimation system and targets for the indigenously developed linear accelerators having various applications have been designed and simulated using Monte Carlo based codes Fluka and Geant4. For 6 MeV medical accelerator and cargo scanner an X-ray target is designed and manufactured. Collimators are essential to accelerators as they define the shape of X-ray beam and restrict its size. They also provide shielding of leakage radiation and attenuation up to 0.1% of the primary beam. For 6 MeV medical accelerator a primary collimator and two sets of secondary collimators have been designed, fabricated and tested. These collimators are made of tungsten. Primary collimator defines the largest available circular field and has a conical opening. Secondary collimator provide a rectangular field at the iso-center. Both simulated and experimental results of beam profile measurements show a fully collimated X-ray beam. Cargo scanners requires a fan like beam to fully scan an object. For such shape a different kind of primary collimators of lead has been designed. The collimator consists of two parts. First is a cylindrical shaped collimator having a trapezoidal slit. The second collimator is rectangular with a trapezoidal slit and is placed at some distance from the first collimator. The cylindrical collimator defines the shape of x-ray beam along with the shielding from leakage radiation. The rectangular collimator only shapes the beam to a fan like structure. These collimators have been designed and simulated in Geant4 and are now in manufacturing phase. Another dual energy radiography system is being developed for which a collimator to focus the beam and to shield the detector system has been designed using theoretical calculations. For this system a dual energy target is also under research phase. The target would be of tungsten and copper brazed together giving maximum x-ray dose and a minimum electron leakage.
A 20 MeV beamline is also under design phase. For this a beam dump and its shielding is being designed using Fluka. A beam dump as the name suggests is a device where the unused beam from accelerator is dumped. It is designed to absorb all energy of the primary beam. Beam dump shielding is required so that the free electrons, neutrons and photons along with the radiation dose caused by the activation of beam dump is stopped.
| Scientific Topic 1 | Source terms, new accelerator facilities and related topics |
|---|---|
| Scientific Topic 4 | Shielding and dosimetry |
| Scientific Topic 7 | Medical and industrial accelerators |
