TY - CPAPER
AU - Ichimiya, R.
AU - Furukawa, K.
AU - Miyahara, F.
AU - Satoh, M.
AU - Suwada, T.
TI - High Position Resolution and High Dynamic Range Stripline Beam Position Monitor (BPM) Readout System for the KEKB Injector Linac Towards the SuperKEKB
J2 - Proc. of IBIC2014
AB - The SuperKEKB accelerator is now being upgraded to bring the world highest luminosity (L=8x10³⁵/cm²/s). Hence, the KEKB injector linac has to produce low emittance and high charge electron (20 mm mrad, 7 GeV/c², 5 nC) and positron (20 mm mrad, 4 GeV/c², 4 nC) beam, respectively. In order to achieve these criteria, the accelerator structure has to be aligned within 0.1 mm position error. Since BPMs are essential instruments for beam based alignment (BBA), it is required to have one magnitude better position resolution to get enough alignment results. We have begun to develop high position resolution BPM readout system with narrow bandpass filters (fc = 180 MHz) and 250 MSa/s 16-bit ADCs. It handles two bunches with 96 ns interval separately and has a dynamic range from 0.1 nC to 10 nC. To compensate circuit drift, two calibration (x-direction and y-direction) pulses are output to the BPM electrodes between beam cycles (20 ms). Since it needs to achieve not only high position resolution but also good position accuracy, overall non-linearity within ±0.02 dB is required and the system has to have more than ±5 mm accurate position range. We confirmed the system performance with a 3-BPM resolution tests at KEK Injector Linac and it turned out that the system has 3 μm position resolution. We plan to install this system during 2015 summer shutdown.
PB - JACoW
CY - Geneva, Switzerland
SP - 637
EP - 641
KW - linac
KW - positron
KW - alignment
KW - electron
KW - rf-amplifier
DA - 2014/10
PY - 2014
SN - 978-3-95450-141-0
UR - http://jacow.org/IBIC2014/papers/wepd04.pdf
ER -