1. 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
Tjeerd Ketel, Nikhef

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

3. Helium sniffer leaks with 2x[10-6 mbar l/s] background12 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
Tjeerd Ketel, Nikhef

4. Sniffer tip at leak 20
Tjeerd Ketel, Nikhef

5. Sniffer tip at leak 20
Tjeerd Ketel, Nikhef

6. 34
Tjeerd Ketel, Nikhef

7. 30
Tjeerd Ketel, Nikhef

8. 15 18
Tjeerd Ketel, Nikhef

9. 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 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.
Tjeerd Ketel, Nikhef

10. Remains of wax at the outside
Tjeerd Ketel, Nikhef

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

12. Possible visible leak (20)

13. Possible visible leak (20)