We analyzed the physical basics for design of absorbers for high energy beams of electrons and photons. Typical examples are the collimators and dump systems. In particular, we considered a collimator for usage in Cornell ERL project, where it could be used for reduction of γ , − e halo, minimization of exposure SRF module to SR from neighboring bending magnet and for absorption of direct beam ...

The American Association of Physicists in Medicine Task Group 36 (AAPM TG-36) data can be used to estimate peripheral dose (PD) distributions outside the primary radiation field. However, the report data does not apply to linear accelerators equipped with a multileaf collimator (MLC) and universal wedge (UW). Tertiary multileaf collimators have been shown to significantly affect PD distribution...

An important method in cancer treatment is the use of high energetic radiation. In order to kill tumor cells the patient is exposed to radiation that is delivered by a linear accelerator whose beam head can be rotated about the treatment couch. Inevitably the healthy tissue surrounding the tumor is also exposed to some radiation. So the problem arises to arrange the treatment in a way such that...

Tantalum-178 is a short-liver radionuclide (T 1/2 = 9.3 min.) and emits primarily 56- to 64-keV characteristic x-rays. We have determined the imaging characteristics with this radionuclide and a large-field-of-view Anger camera. With a pinhole collimator, good spatial resolution is possible with Ta-178, although the image quality is superior with Tc-99m under comparable conditions. Spatial reso...

Shape matrix decomposition is a subproblem in radiation therapy planning. A given fluence matrix A has to be written as a sum of shape matrices corresponding to homogeneous fields that can be shaped by a multileaf collimator (MLC). We solve the problem to find an approximation B of A satisfying prescribed upper and lower bounds for each entry. The approximation B is determined such that the cor...

In this paper, the efficiency and uniformity improvement of non-image LED illumination system with collimator, microlens array and condenser are proposed for pico-projector. The LED light is collimated to 18 degree with efficiency 99.36% by collimator. For image uniformity and flux efficiency, the doule-side microlens array and two condensers are adopted to form a homogenizer. With this homogen...

An imaging displacement sensor (IDS) has been developed that can measure the displacement with an accuracy of 30 nm in 0.03 s with the precision improving to 1 nm for averaging times of 100 s. The IDS consists simply of a light emitting diode (LED) pinhole collimator and a charge-coupled device (CCD) camera chip. The position accuracy is better than 0.05% over the few mm CCD size with deviation...

An integrated imaging sensor system is being developed to enhance operations of robots and telerobotic systems used in nuclear industry . This system combines a gamma ray image of the distribution of radioactivity with a video image of the area, allowing a rapid and intuitive determination of the source location . The gamma ray imaging system is based upon a position sensitive photomultiplier t...