KARIN and KATRIN: A New Technology for High Power 14 MeV D-T Fusion Neutron Generator Tubes for Radiotherapy, Fast Neutron Activation Analysis, Safeguards, Neutron Radiography and Laboratory Applications

Abstract

The Karlsruhe Ring Ion Source Neutron Generator (KARIN) and the Karlsruhe Target Ring Neutron Generator Proposal (KATRIN) are compact, sealed high power, high voltage gas discharge accelerator tubes designed for the generation of 14 MeV neutrons from the fusion reactions of deuterium and tritium ions. The ions originate in a peripheral ring ion source low pressure discharge volume and are guided and accelerated to the center to impinge at a coaxial solid state ScDT metal hydride target sheath on a central watercooled electrode, to release fusion neutrons which may be utilized for various irradiation purposes at the target center or externally near the axis of the system.

Medical and technical applications have been covered partially by the commercialisation of a KARIN tube prototype and its operational system with a source strength warranty up to 5*10¹² n/s and 300 h minimum tube life.

Technical neutron radiography has been performed at the Heidelberg (DKFZ) neutron therapy unit by application of a Pb-converter and PE-moderator and a adjustable Cd-aperture placed into the radiator head exit channel. At a distance of 240 cm from the 12 cm diameter aperture a thermal neutron fluence of 5*10⁸ n/cm² can be realised in one hour irradiation time. Direct Neutron radiographs with the Gd foil method and track etch foils have been made for several applications for nondestructive testing.

The proposed KATRIN tube having a ten fold increased target area, would give a neutron source strength of 10¹⁴ n/s, which for neutron radiographic applications is transformed by a central Pb-converter and PE-moderator to an axially emitted thermal neutron emission flux density of 1.6*10¹¹ n/(s*cm²) over a emission area of 12 cm max diameter to be used for high intensity, large distance neutron radiography and tomography with a movable radiator head.