Space Charge Effect in Spectrometers of Ion Mobility Increment with a Cylindrical Drift Chamber

2007 ◽  
Vol 13 (4) ◽  
pp. 259-272 ◽  
Author(s):  
A.A. Elistratov ◽  
L.A. Sherbakov
Keyword(s):  
Space Charge ◽  
Ion Mobility ◽  
Drift Chamber ◽  
Space Charge Effect ◽  
Single Type ◽  
Charge Effect ◽  
Ion Density ◽  
Focusing Effect ◽  
High Frequency Electric Field ◽  
Order Of Magnitude

We have amplified the model for the drift of ions under a non-uniform, high-frequency electric field by taking space charge effect into account. By this means, we have investigated the effect of space charge on the dynamics of a single type of ions in a spectrometer of ion mobility increment with a cylindrical drift chamber. The counteraction of the space charge effect and the focusing effect is investigated. The output ion current saturation caused by the effect of the space charge is observed. The shape of the ion peak, taking into consideration the space charge effect, has been obtained. We show that the effect of the space charge is sufficient for the relative ion density greater than 10 ppt by order of magnitude (for a cylindrical geometry spectrometer with typical parameters).

scholarly journals Manipulation of Laser Distribution to Mitigate the Space-Charge Effect for Improving the Performance of a THz Coherent Undulator Radiation Source

Particles ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 238-252 ◽  
Author(s):  
Siriwan Krainara ◽  
Shuya Chatani ◽  
Heishun Zen ◽  
Toshiteru Kii ◽  
Hideaki Ohgaki
Keyword(s):  
Electron Beam ◽  
Space Charge ◽  
Electron Bunch ◽  
Beam Quality ◽  
Space Charge Effect ◽  
Bunch Length ◽  
Charge Effect ◽  
Simulation Code ◽  
Undulator Radiation ◽  
Radiated Power

A THz coherent undulator radiation (THz-CUR) source has been developed at the Institute of Advanced Energy, Kyoto University. A photocathode Radio-Frequency (RF) gun and a bunch compressor chicane are used for generating short-bunch electron beams. When the electron beam energy is low, the space-charge effect strongly degrades the beam quality, such as the bunch length and the energy spread at the high bunch charge condition at around 160 pC, and results in the reduction of the highest frequency and the maximum radiated power of the THz-CUR. To mitigate the space charge effect, we have investigated the dependence of the electron beam quality on the laser distribution in transverse and longitudinal directions by using a numerical simulation code, General Particle Tracer GPT. The manipulation of the laser distribution has potential for improving the performance of the THz-CUR source. The electron bunch was effectively compressed with the chicane magnet when the laser transverse distribution was the truncated Gaussian profile, illuminating a cathode. Moreover, the compressed electron bunch was shortened by enlarging the laser pulse width. Consequently, an enhancement of the radiated power of the THz-CUR has been indicated.

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