The background radiation noise contributes to the total noise and signal quality degradation from radiation sensors and cameras. We present equations for the equivalent noise and signal to noise ratio for uncollimated and collimated sensors and cameras. This background noise issue is especially important for applications in medicine where it dictates the image quality at specified radiation intensity and, as a consequence, cancer risks.

Background Noise in Radiation Sensors and Cameras with Collimators and Noise Economic Impact

Noise in radiation camera and camera resolution are largely determined by the radiation attenuation characteristics of the collimators. We analyze the attenuation of cylindrical and conchoidal collimators. We also analyze the possibility of combining conchoidal radiation collimator with adjustable and reconfigurable radiation shields and the potential advantages that can be obtained. We show that the combination can improve the collimation, when the direction of radiation is known, and can also act as a directional filter. The contributions of the study are the analysis of the attenuation of cylindrical and conchoidal collimators in a radiation bandwidth and a configuration for the correction of the directivity pattern in conchoidal collimators for radiation cameras.

Analysis of Conchoidal Radiation Collimators and Shields

The use of collimators and shields for measurements and imaging with X- and γ -rays requires a well-defined
collimation for the pixels and well-determined formula for the effect of the collimators. We analyze the geometric effects
of tubular and pinhole collimators and the effects of curved shields for the case of omni-directional fluxes. These effects
can affect measurements of X- and γ-rays as well as UV rays behind the shield and collimators. On the other hand, such
effects can be used to enhance the capability of multi-spectral sensors by using appropriate covers in front of them.

Horia Mihail H. N. Teodorescu

Papers

Effects of pseudo-lensing and pseudo-dispersion in curved radiation shields and collimators - Effects on measurements