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Research paper : Portable national length standards designed and constructed using commercially available parts (J. Ishikawa)−256−Synthesiology - English edition Vol.2 No.4 (2010) R. B. Hurst, N. Brown, V. D. Dandawate, G. R. Hanes, J. Helmcke, H. P. Layer, L. Zhongyou, W. R. C. Rowley, T. Sakurai and M. S. Chung: International intercomparison of iodine-stabilized helium-neon lasers at 633 nm involving ten standards laboratories, Metrologia, 24 (1), 39-44 (1987).T. J. Quinn: Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001), Metrologia, 40 (2), 103-133 (2003).J. Ishikawa: Wavelength calibration and its uncertainty at 633 nm, Sansoken Keiryo Hyojun Hokoku (AIST Bulletin of Metrology), 4 (1), 71-77 (2005) (in Japanese).Ball Spline Series (Catalog), THK Co., Ltd., Tokyo (2008) (in Japanese).https://tech.thk.com/upload/catalog_claim/pdf/381_ballspline.pdfTHK General Catalog, A8, B8, THK Co., Ltd., Tokyo (2008) (in Japanese).J. Ishikawa: Design and Construction of a 633nm Iodine Stabilized Helium-Neon Laser Based on the CIPM Recomendation, Sansoken Keiryo Hyojun Monogurafu ( AIST Monograph of Metrology), 2(2003) (in Japanese).[1][2][3][4][5][6]AuthorJun IshikawaCompleted the master’s course at the Interdisciplinary Graduate School of Science and Technology, Tokyo Institute of Technology in 1982. Joined the National Research Laboratory of Metrology, Agency of Industrial Science and Technology, Ministry of International Trade and Industry in 1983. Worked on the development of precision interferometer, and was exposed to the iodine stabilized He-Ne laser as a light source for wavelength standard. Joined the National Metrology Institute of Japan, AIST in 2001. Transferred to the Digital Manufacturing Research Center in 2006, where he worked on visualization of skill at the site of manufacturing. Currently, leader of research team for measurement and analysis technology. Received Ichimura Academic Award (The New Technology Development Foundation) in 2006. Received the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology in 2006.Discussion with Reviewers1 Addition to research objective and scenarioComment (Akira Ono, AIST)For Synthesiology, please add the “objective of research” and “scenario for achieving the objective.”Answer (Jun Ishikawa)As you indicated, I added a new section for “objective of research” and “scenario for achieving the objective.” However, this research was started without a scenario (plan), and I frankly explained the course of events at the time.2 Use of AIST Monograph of Metrology in the referenceQuestion and comment (Akira Ono)I think Reference 6 is extremely important in terms of diffusion of this technology. While there is a tendency to write up only the highlights of the original technology in research papers and be done with it, I don’t think I’ve seen a complete disclosure of necessary information to enable reproductive fabrication of the device. What was your motivation for writing Reference 6, and how is it being utilized?Answer (Jun Ishikawa)Unlike the International Prototype Metre Standard Bar, which is an artificial object, the essence of the laser wavelength standard that utilizes the quantum mechanical property of the iodine molecule is in the technology of extracting the optical wavelength from the quantum mechanical property. Therefore, the maintenance and transfer of the standard is the maintenance and transfer of the technology. The AIST Monograph of Metrology was written for the purpose of maintenance and transfer of the technology for the iodine stabilized He-Ne laser. The paper was revised to reflect this thinking. 3 Mass and size of the standardQuestion (Akira Ono)You mention that the national standard can be taken aboard an airplane for transfer. That must be extremely convenient for conducting international comparisons smoothly. What is the mass and size of the newly developed laser? Can it be taken aboard the airplane cabin? Answer (Jun Ishikawa)The body of the laser is 420 mm in length, 105 mm in width, 95 mm in height, and 5.3 kg in weight. The control device is 400 mm in depth, 420 mm in width, 100 mm in height, and 7.5 kg in weight.When boarding the airplane, the laser body is taken aboard the cabin as a hand-carry item, and the control device is checked in. If we concentrate on downsizing and weight reduction, a smaller and lighter laser can be made, but I opted for this size due to the ease of fabrication, assembly, and adjustment.At this point, the greatest barrier to hand-carrying the device on the airplane is the regulation after 9.11. Since the wavelength-stabilized laser is a special device which people are not familiar with, I have a very hard time explaining what it is.4 Uncertainty of laser wavelengthQuestion (Akira Ono)What is your assessment of the uncertainty of the laser wavelength of the new laser? I imagine that it is smaller than the value of uncertainty recommended by CIPM. If possible, can you show the budget table along with the factors of uncertainty?Answer (Jun Ishikawa)Table “a” shows the budget table of the uncertainty of iodine stabilized He-Ne laser recommended by CIPM. Of the uncertainties shown in the table, I think the estimate of the uncertainty caused by one-directional optical intensity within ReferencesNotesNote 1) Currently, the SI Base Units of length is the meter (metre). The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.Note 2) Currently, the helium-neon laser in which the emission frequency (wavelength) is stabilized to the specific absorption line of the iodine molecule is commonly used as the primary standard of length. The frequency recommended is = 473,612,353,604 kHz. Wavelength is calculated by dividing the speed of light c (299,792,458 m/s) by . = c/

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