The Linac Coherent Light Source (LCLS), a pioneer hard x-ray free electron laser is currently under construction at the Stanford Linear Accelerator Center. It is expected that by 2009 LCLS will deliver laser pulses of unprecedented brightness and short length, which will be used in several forefront research applications. This ambitious project encompasses major design challenges to the radiati...

PURPOSE A key factor limiting the effectiveness of radiation therapy is normal tissue toxicity, and recent preclinical data have shown that ultra-high dose rate irradiation (>50 Gy/s, "FLASH") potentially mitigates this effect. However, research in this field has been strongly limited by the availability of FLASH irradiators suitable for small animal experiments. We present a simple methodologi...

The Front End Enclosure (FEE) of the Linac Coherent Light Source (LCLS) is a shielding housing located between the electron dump area and the first experimental hutch. The upstream part of the FEE hosts the commissioning diagnostics for the FEL beam. In the downstream part of the FEE, two sets of grazing incidence mirror and several collimators are used to direct the beam to one of the experime...

The Linac Coherent Light Source (LCLS), the world’s first hard xray free electron laser is under construction at the Stanford Linear Accelerator Center and is expected to be completed in 2009. LCLS will deliver unprecedented bright and short x-ray laser pulses that shall enable frontier new science research in biology, nanomaterials and non-crystalline imaging. Over 400 m of LCLS tunnel have be...

From last 50 years, electron beam therapy has an important radiation therapy modality. The electron beam from the LINAC is of size ∼ 2 mm, whereas the size required for actual treatment is usually larger than 2 × 2 cm up to 25 × 25 cm at the isocenter. In the present work, it is proposed to use dual scattering foil system for production of clinical electron beam. The foils for 6 to 20 MeV elect...

The shielding calculations of bulk shielding for Advanced Proton Therapy Facility (APTRON) which is under design in Shanghai were carried out. The thickness of radiation shielding walls for the accelerator and treatment rooms of APTRON were determined by Monte Carlo simulation and empirical methods [1~3]. Assumptions of beam loss scenarios and workloads of different energy at LINAC, synchrotron...

For the production of a clinical 15 MV photon beam, the design of accelerator head assembly has been optimized using Monte Carlo based FLUKA code. The accelerator head assembly consists of etarget, flattening filter, primary collimator and an adjustable rectangular secondary collimator. Accelerators used for medical radiation therapy generate continuous energy gamma rays called bremsstrahlung r...

Introduction: In radiation therapy with high-energy photon beams (E > 7 MeV) neutrons are generated mainly in LINACs head thorough (γ, n) interactions. These neutrons affect the shielding requirements in radiation therapy rooms. According to the protocol TG-34, photon absorbed dose of 10Gy can cause permanent damage to the pacemaker and the dose of 2Gy can make minor changes in...

Introduction: Neutron contamination is very harmful for the patients receiving radiation therapy due to the high relative biological effect of neutrons. Medical linear accelerators head are made up of materials with high atomic numbers, and High-energy photons interaction with heavy materials can produce neutron contamination. In this study, neutron equivalent dose, neutron spe...