add screen and wire definitions

[roussel-ryan]

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If proposing a new type of lattice element, Please provide:

Element name

Screen, Wire

Element description

Screen: Transverse diagnostic screen that measures detailed 2-dimensional projections of the beam distribution.
Wire: Transverse wire that sweeps across a beam distribution to measure a 1-dimensional beam profile.

List of element parameters

ScreenP:
resolution_x: 0 # [int] Number of screen pixels in the horizontal direction.
resolution_y: 0 # [int] Number of screen pixels in the vertical direction.
pixel_size: 0 # [m] Size of screen pixels.
mirror_x: false # [Boolean] If true, mirror the horizontal image.
mirror_y: false # [Boolean] If turn, mirror the vertical image.

WireP:
angle: 0 # [radian] Angle of the wire with respect to the horizontal axis.
n_steps: 1 # [int] Number of steps used during a wire scan.
start_offset: 0 # [m] Wire scan start offset from beam axis.
end_offset: 0 # [m] Wire scan end offset from beam axis.
width: 0 # [m] Wire width.

Physical model

N/A

Alternative descriptions

N/A

Additional information

Screen implementation examples:
Cheetah: https://github.com/desy-ml/cheetah/blob/master/cheetah/accelerator/screen.py
Bmad/Lux: Detector class in https://www.classe.cornell.edu/bmad/manuals/lux.pdf

[DavidSagan]

A few comments:

• Pixels may not be square so there should be a size for x and y.
• resolution is somewhat cryptic here. How about specifying the index bounds (like the Detector element in Bmad) and that way the mirror_x/y parameters can be eliminated.

[jlvay]

Suggested change

	An Screen element is a transverse profile monitor element that produces a 2-dimensional projection of
	A Screen element is a transverse profile monitor element that produces a 2-dimensional projection of

[wlin6927]

At BNL we use Multi-wire profile monitors (also called harps) to measure 2D beam profile. See (https://proceedings.jacow.org/pac97/papers/pdf/5P048.PDF) for an example in the AGS. I would propose something like the following:

Element name
Multiwire

Element description
Multiwire: Transverse beam diagnostic consisting of arrays of thin wires that intercept the beam and measure the beam intensity distribution along horizontal and vertical axes.

List of element parameters
MultiwireP:
nbr_wires_x: 0 # [int] Number of wires in the horizontal measurement plane.
nbr_wires_y: 0 # [int] Number of wires in the vertical measurement plane.
spacing_x: 0 # [m] Wire spacing in the horizontal plane.
spacing_y: 0 # [m] Wire spacing in the vertical plane.
wire_diameter: 0 # [m] Diameter of the wires.
mirror_x: false # [Boolean] If true, reverse horizontal wire ordering.
mirror_y: false # [Boolean] If true, reverse vertical wire ordering.

In practical data analysis we usually ignore wire diameter since they are very thin, and assume the profile is not mirrored, but I thought it might be good to include them for completeness.

[DavidSagan]

Since there is much overlap let me suggest that one element kind be used for both single and multi-wire elements.