Target Positions

The following table gives a list of target positions and materials. (Listed BDS positions are pre corrections for cryo and vacuum motion). The home position will NOT remove the entire target stack from the beam.

Solid Target Ladder

The following table gives the target foil position, thicknesses and chemical purities.

Target Position	Target	Purity	Thickness g/cm²
Empty	n/a	n/a	n/a
BeO	Ta	99.0%	0.2918 ± 0.0003
Copper	Copper	99.95%	0.17775 ± 0.00015
Thin Carbon	Carbon	99.95%	0.8879 ± 0.0010
Thick Carbon	Carbon	99.95%	2.6547 ± 0.0017

Error in thickness is from measurement of area and mass only. Outside thickness (measured with micrometers) variations in the foils are less than the reported error. Error also does not include possible voids in materials.

Fluid Targets

There are three loops, each with two cells, on the current cryotarget stack. The loop 1 is configured with two 15 cm conflat style cells, the lower of which has a copper bremsstrahlung radiator attached to the front. Loops 2 and 3 are configured with a new helicoflex style gasket on the exit window side of the block. The upper cell on each block is 4 cm and the lower cell is 20 cm. The 20 cm cell is offset 38.39 mm downstream to accommodate large angle scattering. Note that the 20 cm dummy also has this same offset. The following table give the cell and radiator thicknesses for each position on the stack. All cells are made of Al 7075-T6 aluminum alloy.

Target Position	Entrance window thickness (mm)	Exit window thickness (mm)	Wall thickness (mm)	Radiator Thickness (g/cm^2)
Loop 1 top 15 cm	0.115 ± 0.001	0.126 ± 0.009	0.126 ± 0.009	n/a
Loop 1 bottom 15 cm	0.117 ± 0.003	0.118 ± 0.008	0.118 ± 0.008	1.123 ± 0.001
Loop 2 top 4 cm	0.133 ± 0.009	0.153 ± 0.009	0.145 ± 0.011	n/a
Loop 2 bottom 20 cm	0.138 ± 0.008	0.104 ± 0.009	0.138 ± 0.014	n/a
Loop 3 top 4 cm	0.115 ± 0.008	0.142 ± 0.010	0.146 ± 0.011	n/a
Loop 3 bottom 20 cm	0.136 ± 0.008	0.130 ± 0.009	0.150 ± 0.011	n/a

Optics Targets

The optics target has 3 positions. The first position has 3 foils on each at z = ± 7.5 cm and 0; the second has positions at z = ± 2 cm; the third has positions at z = ± 3.8 cm. The following table gives the foil thickness and positions. Carbon foils are 99.95% carbon. Positions less than 0 are upstream from the nominal target center.

Position	Z position	Material	Thickness (g/cm²)
3 foil	Z = -7.5 cm	Al 6061-T6	0.2651 ± 0.0020
3 foil	Z=0	Al 6061-T6	0.2658 ± 0.0020
3 foil	Z = 7.5 cm	Al 6061-T6	0.2672 ± 0.0020
2 foil z = ± 2	z = + 2	Carbon	0.1659 ± 0.0012
2 foil z = ± 2	z = +-2	Carbon	0.1654 ± 0.0012
2 foil z = ± 3.8	z = +-3.8	Al 6061-T6	0.2663 ± 0.0020
2 foil z = ± 3.8	z = +-3.8	Al 6061-T6	0.2600 ± 0.0019

Each of these targets is 25 mm wide at the beam interaction point. Please see picture to get a better view of the configuration.

Dummy Targets

The dummy targets consists of 2 aluminum alloy foils aligned with the end caps of a given cell (i.e. the 4 cm dummy has two foils placed at z = ± 2 cm). The foils are 0.8 cm wide (beam transport x direction). The following table gives the positions and thicknesses of these foils. The alloy is Al6061-T6.

Target	Foil Number	Position	Thickness (g/cm²)
4 cm Dummy	Foil 1	Upstream foil	0.2658 ± 0.0035
	Foil 2	Downstream foil	0.2549 ± 0.0034
20 cm Dummy	Foil 3	Upstream foil	0.2628 ± 0.0035
	Foil 4	Downstream Foil	0.2650 ± 0.0035

Pictures