Saha, P.K. Harada, H. Hayashi, N. Miura, A. Okabe, K. Yoshimoto, M. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-TUPCF12 English 233-236 TUPCF12 ion laser experiment pick-up proton Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-TUPCF12 http://jacow.org/ibic2017/papers/tupcf12.pdf In 3-GeV RCS of J-PARC, an experiment for H⁻ stripping to protons by using lasers is under preparation. The experiment requires measurements of all three charge fractions of each 324 MHz H-μpulse in the downstream of laser and H⁻ interaction point (IP). However, at the first stage, only a single H-μpulse is aimed to strip by using lasers. It is therefore very essential to establish a new measurement method for that purpose, which has not yet been studied anywhere in that direction. We consider measuring BPM (beam position monitor) pickup signal by using an oscilloscope of 4 GHz bandwidth and sampling rate no less than 1TS/s. To test the system, we have done some experimental studies, where beam halo scrapper (carbon foil), placed at the L-3BT (linac to 3-GeV beam transport) is used for H⁻ stripping. The unstripped H⁻ and the stripped protons separated by a bending magnet in the downstream of the scrapper are simultaneously measured by two BPMs in two beam lines. The H-μpulses were clearly measured with good resolution, where a ratio of the pulses without and with scrapper gives the stripping efficiency. A detail of the present study results are presented.