2 Color XFEL
|
The undulator column at SACLA BL3 can be divided into two intervals, each with a different gap to oscillate XFEL at two different wavelengths (figures 1 and 2). After the electron beam has finished its laser oscillation of the first color, it can be diverted with a magnetic chicane, and a time difference can be introduced between the first and second color XFEL pulses. The delay time can be set with an accuracy of several tens of attoseconds, and it is possible to add a delay time of up to 300 fs. In addition, the intensity ratio between the two-color beams can be adjusted by changing the number of undulators involved in the XFEL oscillation (figure 3). |
If you are planning an experiment using two-color XFEL, please be sure to contact the このメールアドレスはスパムボットから保護されています。閲覧するにはJavaScriptを有効にする必要があります。 for information on the available conditions before applying for an assignment. |
Resources:
T. Hara et al., Nature Communications 4, 2919 (2013). |
 |
Figure 1: Diagram of two-color XFEL. By oscillating half of the XFEL in the undulators with a different K value, it is possible to generate two-color XFEL beams. Furthermore, by diverting the electron beam with a magnetic chicane between the 8th and 9th undulators, the XFEL of the second color can be delayed in time with regards to the XFEL of the first color. |
 |
Figure 2: Example of a spectrum at the time of a two-color start. Photon energy can be separated up to approximately 30%. |
 |
Figure 3: A scatter plot of the intensity for each shot when the number of undulators in the first half of the operation is changed. It can be seen that the intensity ratio of the two colors can be significantly changed by adjusting the number of undulators. |
Examples of XFEL beam parameters during two color oscillation: |
|
Color 1 |
Color 2 |
Photon energy |
13.1 keV |
9.7 keV |
Pulse energy |
40 µJ |
40 µJ |
Maximum delay time |
– |
300 fs |
|
|
Color 1 |
Color 2 |
Photon energy |
12.2 keV |
9.7 keV |
Pulse energy |
50 µJ |
30 µJ
|
Maximum delay time |
– |
300 fs
|
|
Color 1 |
Color 2 |
Photon energy |
6.1 keV |
5.9 keV |
Pulse energy |
60 µJ |
60 µJ |
Maximum delay time |
– |
450 fs |
|
|