A U.S. Department of EnergyOffice of Science LaboratoryOperated by The University of Chicago

Argonne National Laboratory

Office of ScienceU.S. Department of Energy

STATUS OF OTR IMAGER FOR THE LCLS UNDULATOR

Bingxin Yang, Jim Bailey, and Dean Walters

Advanced Photon Source

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Pioneering Science andTechnology

Office of Science U.S. Department

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OTR Imager Status

Specifications and designs• LCLS PSD 1.4–004 (cancelled)

• LCLS ESD 1.4–109

• LCLS Tech Note LCLS-TN-05-21 (most complete)

• PAC 05, “Design of a high-resolution optical transition radiation imager for the linac coherent light source undulator,” by B.X. Yang, J. L. Bailey, D. R. Walters, and S. J. Stein.

Outline• Basic design features of the OTR imager

• Current status

• Future?

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Pioneering Science andTechnology

Office of Science U.S. Department

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OTR imager specification

Basic requirements:• RMS resolution: 12 m

• Total field of view: 10 mm (H) 5 mm (V)

• Single shot imaging (1 nC @ 13.64 GeV) desirable

2D Graph 1

X (m)

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OTR imager optics geometry

Design features to obtain good resolution and large field of view simultaneously :(1) Use near normal incidence angle

(2) Tilt CCD camera* to coincide with the tilted image plane.

* CCD camera manufacturer specifies maximum tilt angle allowed.

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OTR imager optics calculation: perfect optics

Specifications without aberrations:• Collection cone angle radius: 0.075 radian

• Diffraction contribution to resolution: 3.2 – 5.6 m (400 – 700 nm)

EFFICIENCY OF LIGHT COLLECTION

RADIUS OF COLLECTION CONE (RADIAN)

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ISOTROPICLIGHT

LIGHT INTENSITY PROFILE NEAR FOCUS

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Collection efficiency Radial distribution Integrated profile

LIGHT INTENSITY NEAR FOCUS

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7 2

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3 10 ln lncollectedN photons Q nC

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4.2res

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Pioneering Science andTechnology

Office of Science U.S. Department

of Energy

OTR imager optics calculation: aberrations

Ray tracing studies for aberrations:• Commercial achromat lenses (M = 1)

• Spherical aberrations unimportant

• Chromatic aberrations dominant contribution

• Use laser mirrors as bandpass filters to improve efficiency

Table 3.12: RMS Size of the PSF from Geometrical Aberration at the Image (2 PAC089) RMS spot size (m) Aperture

size (mm) 550 nm 490–565 nm 515–585 nm 475–645 nm 500–700 nm 400–700 nm 10 0.05 0.8 1.7 1.7 2.9 3.8 15 0.17 1.6 2.5 2.3 4.4 5.8 20 0.36 2.0 3.3 3.2 5.7 7.8 25 0.64 2.9 3.9 3.9 7.0 9.8 30 1.00 4.4 4.4 4.9 8.3 12.0 35 1.37 3.6 5.0 6.0 9.4 14.4 40 1.66 4.5 5.4 7.2 10.5 17.0 45 1.78 5.6 5.8 8.6 11.4 20.0 48 1.71 6.3 6.0 9.5 11.9 22.0 50 1.62 6.9 6.4 10.2 12.2 23.4

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OTR imager mechanical design: partially assembled

Design Parts

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OTR imager intended location: long break sections

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Office of Science U.S. Department

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Summary and future

Summary• Parts are received and partially assembled

• To be tested- Verify resolution- Check resolution over the entire FOV

• Use this package at a different location in LCLS linac? to be studied…- Biggest issue: camera and controls