A compact and comparatively inexpensive system that is practical for universities is described based on a low-energy, electron storage ring with at least one undulator based oscillator to store photons. If the oscillator cavity length is relativistically corrected to be an harmonic of the ring circumference (LC=βLRn=nB with nB the number of bunches), higher-energy, secondary photons from Compto...

We have simulated the head geometry of a Varian Clinac 2100C/2300C medical accelerator in a Monte Carlo calculation to produce photoneutrons and transport them through the head shielding into a typical therapy room (modeled by a test cell at Varian Associates). The fast neutron leakage fluence and energy spectra have been calculated at 7 positions around the linac head for typical beam operatio...

In radiation therapy with high-energy photon beams (E > 10 MeV) neutrons are generated mainly in linacs head thorough (γ,n) interactions of photons with nuclei of high atomic number materials that constitute the linac head and the beam collimation system. These neutrons affect the shielding requirements in radiation therapy rooms and also increase the out-of-field radiation dose of patients und...

Electron accelerators operating above about 10 MeV produce significant quantities of photoneutrons. This is not a new problem and was first reported by Laughlin1 in 1951 for a 23 MeV betatron. In recent years it has drawn considerable attention because of the increased use of higher-energy electron linear accelerators for radiation therapy and also because of the increased awareness of radiatio...

A portable assembly containing a vertical-bend dipole magnet has been designed and installed immediately down-beam of the Compton electron-laser interaction chamber on beamline 1 of the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). The watercooled magnet designed with field strength of up to 0.7 Tesla will be used as a spectrometer in the Thompson scattering and vacuu...

Dose to the total body from induced radiation resulting from primary exposure to radiotherapeutic beams is not detailed in routine treatment planning though this information is potentially important for better estimates of health risks including secondary cancers. This information can also allow better management of patient treatment logistics, suggesting better timing, sequencing, and conduct ...

Detection of several targets (U, Be , D 2 O) interest to national security has been achieved at Purdue University’s 6 MV X-ray clinical linear accelerator (CLINAC), from photoneutron/fission induced neutron signatures using a Centrifugally Tensioned Metastable Fluid Detector (CTMFD). Traditional detection schemes were saturated and ineffective under the intense (to ∼ 10 4 R/h) photon environmen...

Abstract A portable monoenergetic 24 keV neutron source based on the 124 Sb- 9 Be photoneutron reaction and an iron filter has been constructed characterized. The coincidence of energy from SbBe low interaction cross-section with (mean free path up to 29 cm) makes pure specially suited shield against gamma rays Sb decays while letting through neutrons. To increase activity thus flux, a >1 GB...

This investigation focused on the characterization of the lateral dose fall-off following the irradiation of the target with photons, protons and carbon ions. A water phantom was irradiated with a rectangular field using photons, passively delivered protons as well as scanned protons and carbon ions. The lateral dose profile in the depth of the maximum dose was measured using an ion chamber, a ...

background: the characteristics of secondary neutrons in a high energy radiation therapy room were studied using the mcnpx monte carlo (mc) code. materials and methods: two mc models including a model with full description of head components and a simplified model used in previous studies were implemented for mc simulations. results: results showed 4-53% difference between full and with the sim...