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WE-05 | Development of Beam Current Monitor with HTS SQUID and HTS Current Sensor | 109 |
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A highly sensitive beam current monitor with an HTS (High-Temperature Superconducting) SQUID (Superconducting QUantum Interference Device) and an HTS current sensor, that is, an HTS SQUID monitor, has been developed for use of the RIBF (RI beam factory) at RIKEN. Unlike other existing facilities, the HTS SQUID monitor allows us to measure the DC of high-energy heavy-ion beams nondestructively in real time, and the beam current extracted from the cyclotron can be recorded without interrupting the beam user's experiments. Both the HTS magnetic shield and the HTS current sensor were dip-coated to form a Bi2 - Sr2 - Ca2 - Cu3 - Ox (Bi-2223) layer on 99.9 % MgO ceramic substrates. In the present work, all the fabricated HTS devices are cooled by a low-vibration pulse-tube refrigerator. These technologies enabled us to downsize the system. Prior to practical use at the RIBF, the HTS-SQUID monitor was installed in the beam transport line of the RIKEN ring cyclotron to demonstrate its performance. As a result, a 20 μA 40Ar15+ beam intensity (63 MeV/u) was successfully measured with a 500 nA resolution. Despite the performance taking place in an environment with strong gamma ray and neutron flux radiations, RF background and large stray magnetic fields, the measurements were successfully carried out in this study. This year, the HTS SQUID monitor was upgraded to have aresolution of 100 nA and was reinstalled inthe beam transport line, enabling us to measure a 4 μA 132Xe20+ (10.8 MeV/u) beam and a 1 μA 132Xe41+ (50.1 MeV/u) beam used for the accelerator operations at RIBF. Hence, we will report the results of the beam measurements an the present status of the HTS SQUID monitor. |
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