| Paper | Title | Page |
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| THPPH057 | Modeling and Measurement of Mu-Metal Shielding Effect on the Magnetic Performance of an LCLS Undulator* | 718 |
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| In a previous paper (FEL05), we presented results showing that the Earth's field might give a significant effect on the LCLS undulator performance due to a large concentration of the field by the undulator poles. Based on the result of model calculation, we decided to shield the Earth's field by surrounding the undulator backing structure with a 1-mm-thick mu-metal sheet. First, the effect of the shield was modeled using the code RADIA. According to the calculation, the shielding factor of a C-shape mu-metal shield was better than a factor of 8. Second, we measured the Earth's field shielding effect without an undulator. In our measurement laboratory, the vertical component of the Earth's field was 0.5 gauss. It was suppressed to smaller than 0.1 gauss with the shield. After these background measurements, we examined the effect of the shield with an undulator in place. The measurement results show very good agreement with the model calculation. | ||
| THPPH039 | Experimental Study on Effect of Energy Distribution on Transverse Phase Space Tomography | 668 |
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Tomographic method * using a quadrupole magnet and a beam profile monitor is useful method of transverse phase space measurement. However the method is suffered from energy distribution. Therefore we have evaluated the effects numerically. As the result, the low energy tail of the beam distorted the result of tomographic method even with a small amount of the tail **.To confirm the numerical evaluation, measurements have been performed with single slit method, whose result is free from energy distribution. In this conference, the experimental result of two methods will be shown and a new tomographic analysis, which mitigates the effect of energy distribution, is proposed.
* C. B.McKee, et al, NIM A 358 (1995) 264** H. Zen, et al, Proc. of FEL2005 (2006) 592 |