| Autor: |
Thorsten R. Pusch, F. Frommberger, W. C. A. Hillert, B. Neff |
| Jazyk: |
angličtina |
| Rok vydání: |
2012 |
| Předmět: |
|
| Zdroj: |
Physical Review Special Topics. Accelerators and Beams, Vol 15, Iss 11, p 112801 (2012) |
| Druh dokumentu: |
article |
| ISSN: |
1098-4402 |
| DOI: |
10.1103/PhysRevSTAB.15.112801 |
| Popis: |
In order to continuously monitor the intensity and position of an electron beam of a few hundred pA, a system of resonant cavities has been set up. The current measurement relies on signals of a few fW power extracted out of a cylindrical resonator, excited at its TM_{010} mode. The demodulated cavity pickup signal allows the reconstruction of the beam current with a precision of a few pA. For beam position measurements, we designed two resonators, one each for the horizontal and vertical plane. They are excited at their TM_{110} dipole modes, the signal strength vanishing with the beam passing on their symmetry axis. Commercial digital lock-in amplifiers perform a phase-sensitive detection of the position signals, separating them from background noise. A frequency mixing scheme was applied to transform the signals into the passband of the amplifiers. Great care was taken to prevent cross talk by using special shielding. With these techniques, a relative beam position resolution of 50 μm was achieved. The position readings are sampled with a maximum rate of 9 Hz. A standard PC is used to read out the lock-in amplifiers. It transfers the measured raw data as well as processed values to the accelerator control system for graphical display. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
|
