Leaks in box 2 Inside of box 2 has been cleaned from wax Integral measurement shows no leak Box 2 has been heated to 200 0C The integral measurement shows leakage Sniffing with helium inside the box shows 14 leaks 25-05-16 Tjeerd Ketel, Nikhef

Helium sniffer leaks with 2x[10-6 mbar l/s] background collected behind aluminium foil during several hours 25 50 2 4 4 2 25-05-16 Tjeerd Ketel, Nikhef

Helium sniffer leaks with 2x[10-6 mbar l/s] background 12 15 15 60 10 30 15 34 18 15 10 20 5 10 12 15 15 60 10 30 15 34 18 15 10 20 5 10 25-05-16 Tjeerd Ketel, Nikhef

Sniffer tip at leak 20 25-05-16 Tjeerd Ketel, Nikhef

Sniffer tip at leak 20 25-05-16 Tjeerd Ketel, Nikhef

34 25-05-16 Tjeerd Ketel, Nikhef

30 25-05-16 Tjeerd Ketel, Nikhef

15 18 25-05-16 Tjeerd Ketel, Nikhef

Conclusions Also the second the box is leak after heating at 200 oC. With an integral of 10-4 mbar l s-1 at 1 mbar helium overpressure. The leaks are smaller than expected from the integral measurement. Sum is 2 10-4 mbar l s-1 at atmospheric helium pressure. Leaks are found at the thinnest (0.2 mm) parts of the foil. No visible signs of a leak are found at the spotted leaks at the outside of the box. 25-05-16 Tjeerd Ketel, Nikhef

Remains of wax at the outside 25-05-16 Tjeerd Ketel, Nikhef

Possible visible leak (20) Low side edge at beam axis

Possible visible leak (20)

Possible visible leak (20)