Abstract
A Pierce-type electron gun with spherical anode has been numerically computer-aided analysed to yield an appropriate beam with suitable properties valid for different applications. It has been proven that, around a certain value of the aspect ratio, 0.75, the resultant beam geometry could be suitably controlled. The gun geometry plays an important role for beam shaping; parallel, converged or diverged. The minimum electric field required to prevent beam expansion due to space charge effect has been estimated and it is found to be proportional to the cubic root of the distance from the anode to the target (Z<SUP>1/3</SUP>). Also, it is proved that the minimum beam radius is realized at the minimum beam perveance and the maximum beam convergence angle. As a result, this reveals that, the gun geometry controls the beam emittance. The gun design analysis proposed here helps to choose the better operating conditions suitable for low energy electron beam bombardment and/or injection applications.
Highlights
Beams o f charged part icles an d elect ron b eams in particular are being used widely in a great and continuously increasing number of scientific instruments, electron devices and industrial facilit ies[1,2,3]
Iis the electrons current,e is the electronic charge, mis the electron mass,U is the applied acceleration voltage and αis the Langmuir-Blodgett function which depends on the gun geometry as seen in the formu lae[13]: α = δ − 0.3δ 2 + 0.075δ 3 − 0.001432δ 4 + 0.002161δ 5 − 0.00035δ 6 (2)
The estimation of the minimu m electric field required to prevent the electron beam expansion is found to be proportional to one thirds power of the distance fro m the anode to the target (Z1/3)
Summary
Beams o f charged part icles an d elect ron b eams in particular are being used widely in a great and continuously increasing number of scientific instruments, electron devices and industrial facilit ies[1,2,3]. To obtain a beam t rans miss ion withou t p art icles loss, t he cross-section of the beam must not exceed a given maximu m value of a defined point[2]. To achieve this we will introduce an important quantity known as emittance.The emittance is an important aspect for high-quality beam, which is basically defined as the product of width and t ransverse velocity. The results are co mpared to the present electron gun design This is to reveal the parameters and conditions that must be followed to maintain an appropriate output beam matched to the required applicat ion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
