BACKGROUND Megavoltage beams used in radiotherapy are contaminated with secondary electrons. Different parts of linac head and air above patient act as a source of this contamination. This contamination can increase damage to skin and subcutaneous tissue during radiotherapy. Monte Carlo simulation is an accurate method for dose calculation in medical dosimetry and has an important role in optim...

The LAMPF accelerator consists of two 0.75-MeV injectors, one for H + and the other for H − , a separate low-energy beam transport (LEBT) line for each beam species, a 0.75 to 100-MeV drift-tube linac (DTL) operating at 201.25 MHz, a 100-MeV transition region (TR), and a 100 to 800-MeV side-coupled linac (SCL) operating at 805 MHz. Each LEBT line consists of a series of quadrupoles to transport...

Introduction: One of the important problems of using high energy linacs is the production of photoneutrons. High energy medical linacs produce secondary neutrons. These phtoneutrons increase patient dose   Materials and Methods: In this study, the effect of plastic trays on spectrum of photoneutrons produced by 18MV linac is investigated using the MCNP4C code...

The tight tolerances in the main linacs of the Next Linear Collider (NLC) result in a large sensitivity of the beam emittance to slow alignment drifts. Once the accelerator is tuned, the optimized emittances must be maintained. Slow alignment drifts will make resteering and reoptimization necessary. The frequency of these linac reoptimizations is an important parameter that determines how well ...

TRIUMF is funded through to 2005 to proceed with an extension to the ISAC facility, ISAC-II, to permit acceleration of radioactive ion beams up to energies of at least 6.5 MeV/u for masses up to 150. The upgrade includes the addition of a post-stripper superconducting linac to accelerate beams of 3 ≤ A/q ≤ 7 to an energy of at least 6.5 MeV/u. The possibility of using the superconducting linac ...

Linac dynamics simulation capabilities of the PyORBIT code are discussed. PyORBIT is an open source code and a further development of the original ORBIT code that was created and used for design, studies, and commissioning of the SNS ring. The PyORBIT code, like the original one, has a two-layer structure. C++ is used to perform time-consuming computations, and the program flow is controlled fr...

Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. We are investigating the reduction of radium by transmutation on a small scale by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) to produce Ra-225, which subsequently decays to Ac-225, whic...

A novel, compact RF linac structure, the plane wave transformer (PWT), is studied. The PWT provides high accelerating field and high efficiency, and can be used to accelerate high-brightness beams. PWT linac prototypes with eight cells at S-band have been developed at UCLA and successfully used to accelerate an electron beam by more than 10 MeV in 40 cm. In this paper, we describe the principal...

In Korea, when replacing or discarding parts of a medical linear accelerator (linac), self-disposal is required in the consideration activity, but there no standard regulation to manage radioactive waste. The aim this study check activity each part determine disposal time according clearance level for self-disposal. results measuring components linac head disposed Varian, Elekta, and Siemens eq...