11/4/13
R25mm disc. Far zone DR from circular reflector R=25mm with central hole r=5mm, angle =45 deg.
Case presented in the previous reports.
Angular distributions. Intensity normalized, 20GeV, far zone, bunch length
17mkm amplitude factor =7.25, 25 mkm af=2.3, 33mkm af=1.
Wavelength band = 0.2 - 0.02mm
1.0
Intensity
0.8
0.6
0.4
0.2
0.0
-10
0
-5
5
10
Angle, mrad
angle rad vs 17mkm X 7.25
angle rad vs 25mkm X 2.3
angle rad vs 33mkm X1
25X25mm rectangle. 11/4/13 . New calculation. Same as above except that the target is rectangular
25 X 25 mm with hole r=5mm.
Widest distribution corresponds to the bunch length = 33 µm with amplitude factor =0.227,
narrower distribution corresponds to the bunch length = 25 µm with amplitude factor =0.525, and the
most narrow distribution corresponds to the bunch length = 17 µm with amplitude factor =1..67.
One can see that the smaller target radiates wider distributions which makes this reflector
superior to the large reflector.
R12.5 mm disk. 2/13/2014 Newest calculation. Same as above except that the target is disc R=12.5
mm with hole r=5mm.
Widest distribution corresponds to the bunch length = 33 µm with amplitude factor =0.157,
narrower distribution corresponds to the bunch length = 25 µm with amplitude factor =0.364, and the
most narrow distribution corresponds to the bunch length = 17 µm with amplitude factor =1.157.
One can see that the above target radiates wide distributions which makes this reflector also
good.
25 X 25 mm rectangle, 45 deg, horizontal scan at L=40mm, flat , 12,5 *cos 45 =8.84mm
2THz
5 THz
10 THz
15 THz
From the above Figures it follows that the near zone radiation from 25X25mm 45deg radiator has
horizontal width about [-9, 9] mm which corresponds to the projected horizontal width of the radiator
[-8.84, 8.84mm] .
Conclusion: The size of the output window should be a little be larger than the projected size of radiator.
10mm disc. Far zone DR from circular reflector R=10mm with central hole r=5mm, angle =45 deg.
Widest distribution corresponds to the bunch length = 33 µm with amplitude factor =0.073, narrower
distribution corresponds to the bunch length = 25 µm with amplitude factor =0.17, and the most
narrow distribution corresponds to the bunch length = 17 µm with amplitude factor =0.54
The radiator must contain as small as possible irregular surfaces in the vicinity of the main body – flat
mirror with holes and slits . Any irregularity will result in the distortion of the signal which will be
impossible to take into account in calculations and hence to evaluate the pulse length.