Advanced 3He Neutron Detector Prototype with Pad-Readout for the SNS

Neutron detectors under design for the SNS will not be able to exploit fully the expected flux and capabilities of this newfacility. A promising new approach is a 3He detector operating in ionization mode, with discrete pixels that are read-out inparallel. This will provide significant improvements over multi-wire proportional chambers that operate with gas gain. The majorfocus is a prototype detector with collecting area 0.04m2, with counting rate per unit area consistent with that of a full-sizedetector, and without compromises in performance due to space charge effects, aging effects, or electronic pulse pile-up.Challenging issues of placing front-end electronics and digital signal processing inside the pressure vessel will be faced. Theprototype design will permit solutions of fundamental issues to be found, proven concepts then allowing scaling up to a full-sizedetector as an independent construction project. A number of applications will benefit from this development. In SANS for example,SNS will generate about 5 x 107 neutrons s-1 on the face of a 1m2 detector. There is no detector available at present that willoperatecorrectly under such conditions and this program presents a realistic technique to solve this problem.