The muon anomalous magnetic moment (g−2) and the electric dipole moment (EDM) are hot topics in particle physics. There is a significant discrepancy between measurements and theoretical calculations of the muon g−2. The muon EDM violates CP symmetry if CPT symmetry is assumed to be conserved, and it is one of the most sensitive probes to new physics beyond the Standard Model of particle physics. The muon g−2/EDM can be measured using spin precession of muons in a storage ring. At the J-PARC muon facility, we are going to measure the muon g−2/EDM with a new approach using a novel low-emittance muon beam, which is generated by re-accelerating ultra-slow muons (25 meV) to 212 MeV. In this paper, we briefly explain the muon g−2/EDM and the experimental method to measure them, and then the details of the J-PARC experiment is described.
Bulk superconductors are one form of superconducting materials, along with thin films and wires, but from the viewpoint of handling large currents, bulk superconductors are very attractive in that they can handle a large total current at a high current density. In this review, we introduce a new undulator scheme for generating synchrotron radiation by utilizing the high current density of bulk superconductors, and discuss the potential of bulk superconductors in synchrotron radiation technology and its future prospects.
The two-dimensional program for the network survey using Schreiber method was improved from BASIC language to Excel VBA. This program can draw the relative error ellipses. The survey simulation is also useful for estimating the environmental conditions including laser tracker performance. The drill with a three-step countersink is convenient for making floor survey adapters. A data acquisition system such as Keithley 2701 and Pt100 sensors were used for temperature measurements with a resolution of 0.001 degrees. Spectron’s electrolyte tilt sensors are small and capable of precise measurements and measuring instruments were made of these sensors with amplifiers. They are convenient because the analog output from various sensors can be measured simultaneously with a scanner-equipped DMM. Inexpensive dynamic coil geophones such as GS-11D are sufficient for measuring mechanical vibrations, rather than expensive servo-type one.
Radiation damage of undulators operating in storage rings and linear accelerators is a critical problem to be overcome, for stable operation of synchrotron radiation (SR) and X-ray free electron laser (XFEL) facilities. We report on several examples of the radiation damage of undulators recently found in SPring-8 and SACLA, the SR and XFEL facilities that have been operated for more than 25 and 10 years, respectively. It should be noted that these examples of radiation damage are rather surprising, which had not been predicted before starting the operation of the facilities; we discuss the reasons for the unpredicted damage, together with the countermeasures to expand the lifetime of the undulators.
In a fourth-generation light source ring, it is an important issue to establish a safe abort system of the stored electron beams. For this purpose, we formulated the motion of an aborted electron undergoing sinusoidal-patterned kicks by a beam shaker with a constant frequency. It was found that the motion of such an aborted election is essentially equivalent to diffraction of light as long as the betatron tune varies slowly and linearly.
The author, a physicist who takes long-term paternity leave of more than two years, tells a life of a stay-at-home dad in New York. The story includes how he has become a stay-at-home dad, his daily routine, and the calamities he encounters daily.