To: Distribution

From: George Biallas

Subject: Minutes of Meeting on Interference Between the Optical Chicane Diples and the Optical Elements

Date: 2/7/97

Attendees: F. Dylla, G. Neil, S. Benson, M. Shinn, D. Douglas, G. Biallas, J. Bisognano

Issue is that the coatings and optics are in danger of damage by any straight ahead radiation. Four inches of lead and 4 inches of polyethylene are estimated to be needed after the first chicane dipole the optical collimator. The field clamps on the widest configuration envisioned now for the second magnet, interfere by 2 inches with the movement of the mirror chamber to accommodate the 8 inches of total shielding. (The chamber will remain a cylinder to avoid any distortion of the internal optics during pump and after pump down)


The optical collimator will decrease in size by 2 inches to 10 inches in diameter. Gains an inch.

D. Douglas will move the two center magnets along the angle of the beam so that the magnets are closer to one another by 1 inch for each magnet. This gains an additional inch. (Dave has estimated that this will have negligible effect on any electron beam parameters). Dave will revise the DIMAD file accordingly.


All of the available volume in the area will be used to increase the shielding between beam chamber and the optics

M. Shinn will survey the available data for the radiation dose sensitivity for our base optical materials and coatings (no immediate action needed).

Two back-up actions if additional shielding space is needed:

We may be able to gain additional shielding by removing small portions of the corner of the field clamp on the second dipole. As a part of the prototype testing, the effect of moving the field clamp will be investigated.

D. Douglas was unwilling to move the magnets perpendicular to the beam in the initial design. However, actual running experience with the beam will tell us if the magnets may be moved. The stands should be built to accommodate such a move. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ Conclusions of Extraction Chicane Dipole Meeting of 2/3/97

Attendees: C. Bohn, G. Biallas, S. Benson, G. Neil, M. Shinn


* Because of the uncertainty of how the field integral changes across the magnet ends, it is prudent to make the magnets wider by the 1.5 inches shown in the layouts.

* If required, the cartridge can be moved downbeam on the second magnet of the above chicane to avoid conflict with the collimator shielding.

* The lower bus bar/flag should be designed to tuck in closer toward beam axis.

* At the second magnet of the downbeam chicane, the cartridge should be shifted to avoid the cable plug on the mirror mount motors.

* Stands will be sand filled to deaden local vibration from the LCW system.

* Styrofoam may be used as an insulator between magnet and optics if local heating causes unacceptable deflection.