Myriam Newman April 13, 2007 Laser-Wire 1 Myriam Newman LC-ABD Meeting University of Oxford Thursday, April 13 Lens Performance Review Laser-Wire Team Members: Grahame Blair, Stewart Takashi Boogert, Alessio Bosco, Laura Corner, Lawrence Deacon, Nicolas Delerue, Brian Foster, David Howell, Pavel Karataev, Armin Reichold, Roman Walczak

Myriam Newman April 13, 2007 Laser-Wire 2 KEK ATF Laser-Wire Interaction Point Smallest Spot Size at KEK ATF Laser-Wire as of March 2007

Myriam Newman April 13, 2007 Laser-Wire 3 lens How do we use the laser waist to measure the electron beam?

Myriam Newman April 13, 2007 Laser-Wire mm diameter mm 12.7 mm mm mm Lens window mm mm Focus mm Lens Design Lens Type: Doublet of Aspheric and Spheric Triplet Fused Silica System Vacuum Seal

Myriam Newman April 13, 2007 Laser-Wire 5 Lens Study Objectives  Define a metric for how ‘good’ or ‘useable’ the lens is, i.e.:  Define the minimum and maximum tilt in (mrad) for the lens to achieve a 1micron spot size  Determine the angles with which the laser can enter the lens and achieve a 1 micron spot size  Define a translation range for which a 1 micron spot size can be achieved if the laser does not go through the center of lens in (x, y)  Understand the relationship between the spot size, laser waist, and focus position in Z  Understand how the relationship between rotations, translations and how they affect the position of the laser waist, spot size and waist intensity  Develop Alignments Strategy  Use the results to develop future lens designs, simulations, and lens testing procedure

Myriam Newman April 13, 2007 Laser-Wire 6 Z 0 -+ focus Lens Window Profiler Experimental Set Up

Myriam Newman April 13, 2007 Laser-Wire 7 Lens Window Profiler Experimental Set-Up Oxford Laser-Wire Lab

Myriam Newman April 13, 2007 Laser-Wire 8 Exaggerated Lens Tilt Animation Double click on the figure to play video clip

Myriam Newman April 13, 2007 Laser-Wire 9 Best Focus 12/15/06 Near Best Focus

Myriam Newman April 13, 2007 Laser-Wire 10 (au) Roughly 1.5 mm Lens Performance in Tilt

Myriam Newman April 13, 2007 Laser-Wire 11 Roughly 4 mm (au)

Myriam Newman April 13, 2007 Laser-Wire 12 Understanding the lens behavior provides the following pertinent information: The relationship between the lens rotation, waist location, and spot size. How the spot size varies with rotation and shift Where the waist will be in the chamber in relation to the electron beam in order to compensate with the chamber movers How sensitive the spot size growth is when the lens is tilted or the laser enters the lens at an angle A verification and test procedure for testing future lenses that affect future lens design and use Laser-Wire simulations Deriving an alignment procedure for setting up the optics in the experiment

Myriam Newman April 13, 2007 Laser-Wire 13 Comparisons Between Lens Data and Zemax Optical Simulation

Myriam Newman April 13, 2007 Laser-Wire 14

Myriam Newman April 13, 2007 Laser-Wire 15 Θ = Angle Offset sin Θ = length of actuator (mm)________ = radians length of lens mount (74 mm) Front of Lens Mount Length of lens mount = 74 mm Length of actuator (mm) Interested in angle offset, θ, to determine how sensitive the tilt is in mrad. This Value is important for aligning lens at KEK. Overhead View of Lens Mount with Lens Tilt Back of Lens Mount Pivot Point

Myriam Newman April 13, 2007 Laser-Wire 16 Notice how the laser waist and spot change with the tilt of the lens.