Development of a boron-lined proportional detector for startup range of nuclear reactors

It was developed, at IPEN-CNEN/SP, a boron-lined proportional detector to be used at the startup range of PWR type nuclear reactors. Alpha-particles and Li-7 nucleus are produced in the interaction between an incident thermal neutron and boron that line the cathode and both charged particles ionized the gas. The strong electric field between the electrodes multiply the number of electrons closed to the anode and the electric charge collected is proportional to the total number of electrons and also to the energy of the charged particles. In this paper, we presented the different stages of the project, starting with the selection of the detector type, materials, assembling techniques, mixture of gases, filling-pressure and also the functional test performed with the first prototype. (author)