1. Leak tests G. Apeldoorn, P. Vankov 29.01.2004, NIKHEF

2. Leak tests 29.01.2004 Tests are based on using: AFS 1400 – Bidirectional Mass Flow Meter Characteristics of AFS 1400: - dynamic range: 0.03 – 400 sccm -Fast response time: 150 ms -Calibrated & Temperature compensated (for air & Nitrogen) -Digital output signal ( RS-232) (http://www.sensirion.com)

3. Leak tests 29.01.2004 Flow meter opened F1: 1.023e-6 l/s F2: -1.621e-7 l/s F3: -1.391e-7 l/s F4: 1.057e-7 l/s

4. Leak tests 29.01.2004 Flow meter shorted F1: 1.014e-6 l/s F2: -1.441e-7 l/s F3: -1.244e-7 l/s F4: 8.529e-8 l/s

5. Leak tests 29.01.2004 Flow meter Flow meter Temperatures

6. Leak tests 29.01.2004 Connection in series “Brooks” mass flow controller

7. Leak tests 29.01.2004 Leak test of Module 5012 (5m prototype) (N) Flow meter F1 Bubbler (8 mbar) closed Module 1 2 Steps: 0. Tap 2 is always closed. 1.Tap 1 is opened, gas is pumping the module in. 2.Tap 1 is closed, module is under 8 mbar overpressure, F1 is measuring. Leakage criterion: Leakage flow must be of the order (or less) of 1e-6 l/s.

8. Leak tests 29.01.2004

9. Flow meter F1 Module F2 Flow meter straw outer Gas Gas volumes (straw/outer) separation

10. Leak tests 29.01.2004 Gas volumes (straw/outer) separation Flow meter F1 Module F2 Flow meter straw outer Gas

11. Leak tests 29.01.2004 How to proceed ? -Better tubes & taps -Atmospheric pressure & temperature monitoring -Flow controller -Nitrogen/Argon