Y. G. Jung

Conceptual design of a 14 cm period multipole wiggler at PLS

Pohang Accelerator Laboratory (PAL) is developing a Multipole Wiggler (MPW14) to utilize high-energy (B30 keV) synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device to achieve maximum peak flux density and wide beam fan that can serve two beamlines. PLS MPW14-features period of 14 cm, minimum gap of 14 mm, 20 full field periods, maximum flux density of 2.06 T, 3036 mm total magnetic structure length. The peak flux density is very high compared to the other wigglers of similar pole gap and the period. The high peak flux density was possible using advanced new magnetic material and optimized magnetic geometry. The MPW14 will be used in hard X-ray region of 10–30 keV at 2.5 GeV electron energy. The total photon power is 6.19kW and the peak power density is 5.27 kW/mrad 2 at 2.5 GeV, 150 mA. To withstand the big magnetic loads with minimum deflections, C-type support structure is designed with detailed FEM structural analysis. In this article, all the conceptual design efforts for the PLS MPW14 wiggler will be described. r 2001 Elsevier Science B.V. All rights reserved. PACS: 41.85.L

Design of High Field Multipole Wiggler at PLS

Pohang Accelerator Laboratory (PAL) is developing a high field multipole wiggler for new EXAFS beamline. The beamline is planning to utilize very high photon energy (∼40keV) synchrotron radiation at Pohang Light Source (PLS). To achieve higher critical photon energy, the wiggler field need to be maximized. A magnetic structure with wedged pole and blocks with additional side blocks which are similar to asymmetric wiggler of ESRF are designed to achieve higher flux density. The end structures were designed to be asymmetric along the beam direction to ensure systematic zero 1st field integral. The thickness of the last magnets were adjusted to minimize the transition sequence to the fully developed periodic field. This approach is more convenient to control than adjusting the strength of the end magnets. The final design features 140mm period, 2.5 Tesla peak flux density at 12mm pole gap, 1205mm magnetic structure length with 16 full field poles. In this article, all the design, engineering efforts for the ...

Design of Switching Magnet for 20-MeV Beamlines at PEFP

The PEFP (Proton Engineering Frontier Project) proton linac is designed to have two proton beam extraction lines at the 20-MeV and 100-MeV end. The 20-MeV extraction line is branched out into 5 beamlines by using the switching magnet. The magnet bends the proton beam by +20, +10, 0, -10, -20 degrees, respectively, and has an AC frequency of 2.5 Hz with a programmable ac power supply. It employs an H-shape, 0.45 T magnetic fields, 500 mm effective length, and 50 mm pole gap. Laminated steel of 0.5 mm reduces the eddy currents in the yoke, but some heat radiation from the stainless steel of vacuum chamber is inevitable. This paper presents the magnet specification and primary design.

Development of a Precision Amplifier for the Detector

A trans-resistance amplifier has been designed and tested to measure the intensity of synchrotron radiation at Pohang Light Source (PLS). The front-end stage of the amplifier was implemented using discrete circuit elements and can measure input current in the range of 1 pA to 1 μA. A microprocessor interfaces the amplifier with computer and controls the other sub-circuits for synchrotron radiation measurement. The amplifier was tested and obtained a resolution of ∼ 20 fA, a temperature drift of ∼ 0.1 pA/°C, and a signal-to-noise ratio greater than 80 dB.

Development of 14 cm Period Wiggler at PLS

Pohang Accelerator Laboratory (PAL) is developing a 14 cm period wiggler (MPW14) for high flux material science(HFMS) beamline. The MPW14 is a hybrid type device achieving higher peak flux density. PLS MPW14 features period of 14cm, minimum gap of 14mm, 24 full field poles, maximum flux density of 2.02 Tesla, and the total magnetic structure length of 2056mm. The peak flux density is higher compared to the other wigglers of similar pole gap and period. The high peak flux density has been achieved by using advanced new magnetic materials and optimized magnetic geometry. The magnetic performance of the MPW14 is measured using a conventional hall probe scanning system and flipping coil system. The newly developed angularly resolved flipping coil measurement system is very precise and fast. Due to its angular resolving feature, all higher order multipole contents of the MPW14 could be measured. In this article, all the developments efforts for the PLS MPW14 wiggler and the efforts for the angularly resolving flipping coil measurement system are described.

Optimization of EPU6 undulator at PLS

Pohang Accelerator Laboratory (PAL) is developing an Elliptically Polarized Undulator (EPU) to produce polarized synchrotron radiation at Pohang Light Source (PLS). The EPU6 is an Apple-II type elliptical undulator, which changes the polarization of the field by translating the quadrant arrays. The PLS EPU6 features a period of 6 cm, a minimum gap of 19 mm, 25 full field periods, a maximum vertical flux density of 0.69 T, a maximum horizontal flux density of 0.46 T, and 1575 mm total magnetic structure length. The EPU6 is optimized for highly polarized synchrotron radiation from 117 to 1500 eV at 2.5 GeV electron energy. Using correction coils to compensate the orbit drift in the undulator increased the estimated photon flux by 15% compared to the case without the compensation.