Update of the damage tests at SQS.

Yesterday (15.04) SQS staff created a focused beam on our sample using a small YAG fragment we have placed on the holder.

Due to the unusual position, the beam is full of aberrations but it looked small enough for our purpose. Estimattion of the size is difficult atm but it is our intention to measure it with imprints.

We managed to align the sample 1 (silicon, uncoated) in grazing incidence at 19 mrad and found the damage threshold at current focusing conditions at around 100 uJoule (looking on the SQS XGM).

We managed to align also on sample 2 (silicon, B$C coated) at the same grazing angle and we found a threshold at around 200 uJoule.

We started to do systematic spots at various energies, using the GATT

One difficulty is that the manipulator is not enough precise to scan several mms in grazing incidence, the sample has to be realigned along the scan and we cannot find a clear centering on the sample due to the lack of reproducibility.

In the late shift we started to do imprints to characterise the beam spot.

Overall the experiment is on a very good status. Until now, we explored only single pulse damage. Today (16.04) we will try multipulse damage and single pulse damage at 9 mrad.

 

Today we comtinued the program, changing to 9mrad amd 15mrad and doing also multipulse. We had a short interruption at around 15 to extract some samples and to realign Sample 3.