Proton beam spot size and position measurements using a multi-strip ionization chamber.

Purpose: To develop and characterize a large-area multi-strip ionization chamber (MSIC) for efficient measurement of proton beam spot size and position at a synchrotron-based proton therapy facility.

Methods And Materials: A 420 mm x 320 mm MSIC was designed with 240 vertical strips and 180 horizontal strips at 1.75 mm pitch.

Verification of initial-and-final-state opacity for unambiguous weighted automata.

Initial-and-final-state opacity (IFO) is a type of opacity that characterizes a system's ability to prevent the disclosure of information about whether its evolution starts at an initial state and ends at a final state. In this paper, we extend the notion of IFO from the logical automata to the framework of unambiguous weighted automata (UWAs) that do not contain any cycle composed solely of unobservable events. For the verification of IFO, we first construct a labeled observer and a trellis-based initial state estimator for a given UWA.