Target density this morning had stabalised at 7e11 at/cm2

This is sufficient to test the beam/target overlap using the lifetime of the beam in the ring.

Previous attempt at this method was done at 1.5e11 at/cm2 where lifetime from residual gas and target are essentially the same.

Beam set to bunched. Beam position varied by 1mm and the number of particles in the ring taken from Grafana plots. Particles at injection compared with at dump.

Significantly more beam loss at > 8 mm beam position with highest value at 8.75 mm. This is the maximum we can move the beam.

Test repeated with no target. Same beam loss rate for all positions. We see a clear difference with the target only at positions > 8mm.

Test repeated with original electron cooler voltage Gleb tuned with last night. Same outcome -> cooler voltage has no significant impact on overlap (for 0.1V at least)

Overlap using count rate over 7.5 minutes also tested. DSSD 1 (top right) used as gauge as no beam stripe is seen in this detector. 

At horizontal position 4 mm (previous estimation of overlap) we saw a small increase in counts around 4.7 MeV with the target off compared to target on (76 vs 57)

At horizontal position 8.75 mm we saw a large decrease in counts around 4.7 MeV with target off compared to target on (95 vs 290)

It appears clear the overlap is at 8.75 mm. Future runs will use this as horizontal beam position.