Browse Prior Art Database

Low dark current accelerator using drift tube

IP.com Disclosure Number: IPCOM000012470D
Publication Date: 2003-May-08
Document File: 3 page(s) / 147K

Publishing Venue

The IP.com Prior Art Database

Related People

Ken Witham: INVENTOR [+6]

Abstract

A linear charged particle accelerator, having the improvement of a drift tube between the electron gun and accelerating cavities such that a problem, commonly known as 'dark current', is minimized.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Ref. No. 2002E18837US

SUPPLEMENTAL SHEET FOR INVENTION DISCLOSURE

ABSTRACT

A linear charged particle accelerator, having the improvement of a drift tube between the electron gun and accelerating cavities such that a problem, commonly known as 'dark current', is minimized.

BACKGROUND INFORMATION

A problem encountered with charged particle accelerators is one known as 'dark current' in which uncontrolled beam acceleration occurs when the electron gun is turned off and the RF power is turned on. One of the major causes of dark current is unwanted coatings of materials from the electron gun on high field surfaces within in the accelerating structure. These coatings will lower the work function of the surface, such that electrons can be pulled from them and accelerated. The coatings, e.g. barium-oxide, emanate from particles that are boiled off of the gun cathode over time.

DETAILED DESCRIPTION

The drift tube creates a low field region, as shown in the first figure below, which forms a spatial filler so that material emanating from the gun will deposit primarily in this region and not the high field region in the accelerator cavities. The field strength in the 'low field region' is such that electrons will not be pulled from these surfaces, even if they are covered with coatings that lower their work function. Also shown in this figure is a focusing solenoid that may need to tie added around the drift tube to improve efficiency of the accelerator.

Prototype tests presently underw...