A high-efficiency collector for a high-voltage electron cooler

A high-perveance collector with a small secondary emission ratio has been designed for a high-voltage electron cooler. The distinctive feature of this collector is the fact that it consists of the cooled collector itself, which receives the electron flow, and a Wien filter installed ahead of it, which substantially reduces the secondary electron flux emerging from the collector. The main advantage of this design is the combination of the small secondary emission ratio and the high perveance with the small size and ease in manufacturing and adjustment. The results of calculations and experimental investigations of the combined collector are presented, and its different operating modes are investigated. The minimum attained secondary emission ratio is 5 × 10−6. The methods for further reducing this ratio are proposed.