NSRRC Activity Report 2022

094 NSRRC ACTIVITY REPORT 2022 solution to achieve high stability and PSR. (Reported by Fu- Yu Chang, Zong-Kai Liu and Meng-Shu Yeh) With PDCL Energy saving off Standby I cc (A) 1.81 4.90 Injection time (s) 2 2 Stand by time (s) 240 240 Cycle (s) 242 242 Standby power (kW) 61 -- Injection power (kW) 155 155 Power/cycle (kW s) 14,950 37,510 Power/year (kW h an -1 ) 527,821 1,324,320 PSR (%) 60.1 0.0 References 1. M.-S. Yeh, C. Wang, L.-H. Chang, F.-T. Chung, T.-C. Yu, M.- C. Lin, L.-J. Chen, T.-T. Yang, M.-H. Chang, Y.-H. Lin, M.-H. Tsai, C.-H. Lo, Z.-K. Liu, Nucl. Instrum. Meth. A 775 , 46 (2015). 2. M. S. Yeh, F. T. Chung, L. H. Chang, L. C. Chen, C. H. Lo, M. C. Lin, C. Wang, K. T. Hsu, IPAC’ 09 , WE5P- FP090, 2222 (2009). 3. F.-T. Chung, M.-S. Yeh, F.-Y. Chang, L.-J. Chen, T.-C. Yu, Z.-K. Liu, L.-H. Chang, M.-H. Chang, C.-H. Lo, Y. T. Li, S.-Wen Chang, C. Wang, M.-C. Lin, IPAC’ 18 , THPAL046, 3748 (2018). 4. F.-Y. Chang, Z.-K. Liu, M.-S. Yeh, M.-C. Lin, C. Wang, S.- W. Chang, Y.-D. Li, L.-J. Chen, F.-T. Chung, C.-H. Lo, M.- H. Chang, Nucl. Instrum. Methods. Phys. Res. A 1045 , 167623 (2023). A pulsed wire system was established for measuring the magnetic field of an in-vacuum undulator at the NSRRC in Taiwan. 1 A CuZr wire (length: 4 m, diameter: 100 μm) is used, and the pulse current is generated using an in-house power supply. A high-resolution, rapid-feedback laser-photodiode system is used to detect wire displacement. A NdFeB permanent magnet in-vacuum undulator (period: 22 mm, magnetic length: 2 m) was constructed for the Taiwan Photon Source (TPS). For this application, we employed a thin, highly stiff CuZr wire to reduce the maximum sag during the measurement of the long undulator. We compared the magnetic field measurements obtained with the pulsed wire with those obtained with a Hall probe. Introduction An in-vacuum undulator is a key insertion device for synchrotron radiation. The permanent magnet of the in-vacuum undulator is critical for the TPS at the NSRRC. Before installation in the storage ring, the magnetic fields of the undulators were measured during operational pauses. Typical methods for measurement of the magnetic fields of in-vacuum undulators use Hall probe and stretched wire measurements. In 1988, Warren first used a pulsed wire method to measure the integral field of a wiggler. 2 In addition to measuring the magnetic fields of undulators, pulsed wire measurements can be used for magnet alignment. In this study, we focused on the measurement of the magnetic field of a long undulator. Pulsed Wire Measurement at the NSRRC The theory of pulsed wire measurement is based on the Lorentz force and a general traveling wave. Short and long current pulses are used for first and second integral measurements, respectively. The wire displacement and can be written as 3 ................................................... (1) .................................... (2) where I is the magnitude of the current, δt is the current pulse width, T is the wire tension, and C o is the wave velocity. Figure 1 shows the pulsed wire system installed on an in-vacuum undulator, which contains a CuZr wire, an in-house power supply, two oil dampers, and a wire-displacement detection system. Pulsed Wire System for Magnetic Field Measurements Table 1 : Power consumption with the PDCL. PSR = × 100% P Energy saving o P Energy saving o – P x U 1 st (t) = ∫ 0 C t B y ( z ) dz IC δt 2T U 2 nd (t) = ∫ 0 C t ∫ 0 C t’ B y ( z ) dzdz’ I 2T << λ U C 0 > L C 0 ∆ t1st ∆ t2nd PSR = × 100% P Energy saving o P Energy saving o – P x U 1 st (t) = ∫ 0 C t B y ( z ) dz IC δt 2T U 2 nd (t) = ∫ 0 C t ∫ 0 C t’ B y ( z ) dzdz’ I 2T << λ U C 0 > L C 0 ∆ t1st ∆ t2nd