# Presentation: 079955

## FNAL Pbar Target StationOverview and Target Issues

- Jim Morgan
- High-Power Targetry Workshop
- September 9, 2003

## Aerial photograph of Pbar Source

## Pbar Target Vault

## Workers in target vault

## Lithium Lens

## Single turn 3-degree pulsed magnet

## Gear drive target assembly

## Target stack showing cooling disk

## Pbar target assembly presently in use

## Preparing for more protons on target

- Beam Studies
- Quantify spot size vs. pbar yield relationship for spot sizes below =0.15 mm
- Look for evidence of yield reduction due to melting
- Attempt to create single pulse damage to copper disk
- Alternative target material
- Identify target materials that are superior to Nickel in longevity while minimizing the loss of normalized yield
- Examine damage to old targets
- Beam Sweeping
- Commission sweeping system to reduce peak energy deposition in the target
- Investigate the possibility of running with only the upstream sweeping system

## Damage to titanium cover and nickel target

## Target material comparison

| Target Material | Iridium | Rhenium | Tungsten | Nickel | Copper |
| --- | --- | --- | --- | --- | --- |
| A1/3/(m3/Kg) | .255 | .271 | .295 | .437 | .445 |
| A1/3/(Normalized) | 1.71 | 1.61 | 1.48 | 1 | .98 |
| Observed Yield (Normalized) |  |  | 1.05 | 1 | .99 |
| Melting Point Energy (J/g) | 460 | 610 | 630 | 1,250 | 770 |
| Yield Strength (kPa) | 160 | 270 | 500 | 230 | 72 |
| Gruneisen parameter (kPa Kg/J) | 80.6 | 66.0 | 31.0 | 15.8 | 17.2 |

## Energy deposition vs. peak target temperature

## Energy deposition vs. peak target temperature

## Apparent target depletion due to melting

## Damage to Tungsten-Rhenium target

## Damage to Tungsten target

## Early target assembly

## Holes in Copper Target

## Old target assembly with cover removed

## Bulges on titanium target cover

## Target damage to nickel target (entry)

## Target damage to nickel target (exit)

## Pbar yield and peak energy deposition vs. spot size

- Nickel target, 5E12 protons

- McLens and CASIM Models

## Comparison of model and data yield curves

## Summary of target material endurance study

| Material  | Spot size | Starting
Yield | Ending
Yield | Protons
On target | Yield reduction
Scaled to 1018 protons |
| --- | --- | --- | --- | --- | --- |
| Nickel 200 | xy = 0.15, 0.16  | 1.000 | 0.970
 | 5.7 x 1017 | 5.3% |
| Nickel 200 | xy = 0.22, 0.16 
 | 0.990
 | 0.935 | 6.6 x 1017 | 8.3%
 |
| Inconel 600 
 | xy = 0.15, 0.16 
 | 0.995
 | 0.970
 | 10.6 x 1017 | 2.4%
 |
| Inconel 600
 | xy = 0.22, 0.16 | 0.990
 | 0.960
 | 10.7 x 1017 | 2.8%
 |
| Inconel 625 
 | xy = 0.22, 0.16 | 0.980
 | 0.970
 | 6.6 x 1017 | 1.5%
 |
| Inconel X-750 
 | xy = 0.15, 0.16 
 | 0.985
 | 0.965
 | 5.7 x 1017 | 3.5%
 |
| Inconel 686 
 | xy = 0.15, 0.16 
 | 0.970
 | 0.935
 | 1.0 x 1017 | 38.2%
 |
| Stainless 304 | xy = 0.15, 0.16 
 | 1.000
 | 0.965
 | 6.1 x 1017 | 5.8%
 |

## Upstream sweeping magnets installed in AP-1 line

## Pbar target and beam sweeping, Summary

- Pbar Target and Beam Sweeping
- Inconel® 600 identified as operational target material
- Although Inconel® X-750 and Stainless 304 aren’t bad
- There may not be a benefit in reducing spot sizes to the original goal of σ = 0.10 mm
- Beam studies show spot sizes below σ = 0.15 mm produce little or no antiproton yield as much as models predict
- Target damage and yield reduction are not as severe as expected at small spot sizes
- Single pulse target damage observed with copper
- Energy deposition a factor of 3 above that required for the onset of melting
- Yield reduction from target melting has not been observed
- Upstream beam sweeping system is ready for  testing with beam