• T. Kume, K. Furukawa, M. Satoh, T. Suwada
  KEK, Ibaraki
• E. Okuyama
  Akita University, Akita

Profile shape measurements detecting profile slope angle, which corresponds to the differential of the profile shape, have been used for evaluating profile shapes highly precisely. They are hardly affected by scanning error in measurement and considered to have advantages for long distance measurements. Here, profile measurement using a level was adopted for straightness alignment of the KEK e-/e⁺ injector linac, considering the straightness alignment as a profile shape measurement. The slope angles between the alignment base plates of the linac could be detected with reproducibility of 10 micro-rad (σ) by sequential measurement interval of 1 to 2 m. The reproducibility of the straightness derived from the angle measurements was 42 micrometer (σ) for 69 m of the measurement distance and agreed well with the estimated value based on our error propagation model. These results show that straightness reproducibility of better than 1 mm (2-σ) can be achieved for 500 m of the KEK e-/e⁺ injector linac by sampling interval of 2m, and for 10 km of the ILC linac by sampling interval of 20 cm.