Abstract
The Pohang Accelerator Laboratory’s X-ray free-electron laser (PAL-XFEL), a 4th generation light source, is currently being installed and will be completed by December 2015 so that users can be supported beginning in 2016. The PAL-XFEL equipment must continuously maintain the bunch-tobunch beam parameters (60 Hz, Energy: 10 GeV, Charge: 200 pC, Bunch Length: 60 fs, Emittance X/Y: 0.481/0.256 mm rad) in order to supply stable photons with the energy and flux appropriate for tests by beamline users. To this end, the PAL-XFEL equipment has to be kept precisely aligned (Linear Accelerator: +/− 100 μm, Undulator: +/− 50 μm). As a part of the process for installing the PAL-XFEL, a GPS-using surface geodetic network is being constructed for precise equipment measurement and alignment, and the installation of a tunnel measurement network inside the buildings is in the preparation stage; additionally, the fiducialization of major equipment is underway. After the PAL-XFEL equipment is optimized and aligned, if the ground and the buildings go through vertical changes during operation, misalignment (and tilt) of the equipment, including various magnets and RF structures, will cause errors in the electron beam’s trajectory, which will lead to changes to the beam parameters. For continuous and systemic measurement of vertical changes in the buildings and monitoring of ground sinking and uplifting, the Budker Institute of Nuclear Physics (BINP) Ultrasonic-type Hydrostatic Levelling System (HLS) is to be installed and operated in all sections of the PAL-XFEL for the linear accelerator, the insertion device (undulator) and the beamline. This study will introduce the operation principle, design concept, and advantages (self-calibration) of the HLS and will outline its installation plan and operation plan.
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References
R. E. Ruland, “Some Alignment Considerations for the Next Linear Collider” SLAC-PUB-7060.
R. Staiger, “Push the Button - or Does the Art of Measurement Still Exist?” FIG Working Week, Israel, 2009.
D. Martin, Proc. of 7th IWAA (SPring-8 Hyogo, Japan, 2002).
A. Herty, G. Gassner and J. Volk, Proc. of 11th IWAA (DESY Hamburg, Germany, 2010).
C. Zhang, K. Fukami and S. Matsui, Proc. of 7th IWAA (SPring-8 Hyogo, Japan, 2002).
C. Zhang, K. Fuami and S. Matsui, Proc. of 8th IWAA (Geneva, Switzerland, 2004).
S. Singatulin, J. Volk, V. Shilsev, A. Chupyra, A. Medvedko and M. Kondaurov, Proc. of 9th IWAA (SLAC California, United States, 2006).
S. Takeda, A. Akiyama, K. Kudo, H. Nakanishi and N. Yamamoto, Proc. of 2nd IWAA (DESY Hamburg, Germany, 1990).
Michael A. Ainslie, Principles of Sonar Performance Modeling (Springer, 2010).
A. G. Chupyra, G. A. Gusev, M. N. Kondaurov, A. S. Medvedko and Sh. R. Singatulin, Proc. of 9th IWAA (SLAC California, United States, 2006).
A. G. Chupyra, G. A. Gusev, M. N. Kondaurov, A. S. Medvedko, R. V. Pilipenko and Sh. R. Singatulin, Proc. of 10th IWAA 2008 (KEK Tsukuba, Japan, 2008).
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Choi, HJ., Seo, KW., Gil, KH. et al. Use of the BINP HLS to measure vertical changes in the locations of the building and ground at the PAL-XFEL. Journal of the Korean Physical Society 69, 998–1004 (2016). https://doi.org/10.3938/jkps.69.998
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DOI: https://doi.org/10.3938/jkps.69.998