| Paper | Title | Page |
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| MOPE037 | Measurement of Beam Size at Pohang Light Source | 1056 |
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The synchrotron-radiation interferometer was employed for the beam size measurement of electron beam circulating in the storage ring at 2.5 GeV Pohang Light Source. We measured the beam sizes in both vertical and horizontal directions as function of stored beam current. In this presentation, we will discuss the interferometer system, analysis method for the measurement and the measured results. We also compared the measured beam sizes with predicted values from the lattice parameters in the ring. |
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| MOPE039 | Beam Parameter Measurements of fs-THz Linac at PAL | 1059 |
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At Pohang Accelerator Laboratory, a femto-second THz facility was constructed for the experiments using femto-second THz radiation. The fs-THz radiation is generated from 60-MeV electron linac which consists of a photocathode RF gun, two accelerating columns, and two magnetic-chicane bunch compressors. The coherent transition radiation (CTR) is used for THz radiation generation. To generate high intensity THz radiation, the electron bunch length should be smaller than 200 fs. We report THz image obtained using IR-CCD camera and measured beam parameters including bunch length, energy spread, charge, emittance, and transverse beam size. |
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| TUPEC014 | Upgraded Photocathode RF Gun at PAL | 1740 |
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A Brookhaven National Laboratory (BNL) type S-band photocathode RF gun is used at Pohang Accelerator Laboratory (PAL) to produce femtosecond tera hertz (fs-THz) radiation. In order to upgrade the fs-THz Facility at PAL, we need to develop the performance of the RF gun. The requirements for new RF gun are following: 1 nC beam charge, 60 Hz repetition frequency and 1 mm mrad normalized rms transverse emittance. A dual feed photocathode RF gun is designed satisfy these requirements. Two additional pumping ports are used to remove the field asymmetry. A large radius and short length of the iris increases the mode separation. The coupling scheme is changed to make the fabrication simpler. The RF gun structure had been modeled using 3D field solver to provide the desired RF parameters and to obtain the field profile. In this paper the new RF gun design and the cold test results will be presented. |
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| THPE011 | Coupling Diagnostics and Control at PLS Storage Ring | 4533 |
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The measurement and the control of the coupling is essential to maximize synchrotron performance. Small coupling is required for small vertical size and high brightness. The Pohang Light Source has a 2.5 GeV storage ring and its coupling constant is measured as about 1%. In addition to errors at quadrupole or sextupole, the condition varying of the insertion device affects the coupling. The coupling for various condition is measured by the resonance and the response matrix and compared with the beam size and the lifetime. The correction and the control of the coupling is presented. |
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| THPE073 | Experimental Study of Spurious Mode in the PLS and PLS-II Storage Ring Vacuum Chamber | 4686 |
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A superconducting RF cavity is used in the storage ring of the Pohang Light Source (PLS) upgrade project (PLS-II) at Pohang Accelerator Laboratory (PAL) for increasing the electron beam current and energy from 2.5GeV/200mA to 3.0GeV/400mA. In order to meet the requirement of lower beam emittance and higher photon energies, as well as more straight sections for insertion devices, the vacuum chambers in the storage ring need to be reconstructed. To control the spurious harmonic resonances' effect to beam position monitors (BPMs) in the PLS and PLS-II storage ring vacuum chamber, the TE mode distribution in vacuum chambers has been analyzed by both numerical simulation and experiment. Based on this analysis, the proper method to control the strength of TE mode at the position of BPMs is suggested. |