InitialRuns

Here we discuss recent issues with earlier fridge runs.

Leaktesting 16th February 2011

When warming up the traps on the 14th of February a lot of material was shown to come out of the traps, up to 341mbar. This was acomplished by opening opeing the traps (valves 5 and 16) to the P3 pressure gauge (open A9) and allowing the traps to warm while the pressure was recorded on P3. We reached 341mbar and then pumped the traps out to air via pump 4 (open A9 and A8).

the leak detector is connected to PORT AUX-1 (valve M3) and A9 is opened while the leak detector pumps down and during leak detection.

As this could indicate a leak to air or leak from the mixture we resolved to test the following:

1. The traps (bottom weld, top weld, clamps x2 at the top, and clamps (to and from traps) at the gas handling cabinet (GHC).
2. The still line (T-bar on GHC, in GHC and on the fridge).
3. Inside the gas-handling cabinet (all connection points).

Note: L/R = Leak Rate (fore-vacuum pressure), P2= pressure at the test connection, and GHC= Gas Handling Cabinet.

Testing the traps:

The testing sequence was as follows:

Time HH:MM	Action	Open valves	Pressure _mbar.l/s_ (L/R), mbar (p2)
1430	-	M3, A9	L/R=4×10-5 and dropping, P2=1.1×0-2
1437	spray around valve 15 in GHC	M3, A9	No change.
-	Open 5	M3, A9,5	L/R= drops to 1×10-6
-	Close 5	M3, A9	L/R= 9.5×10-7 and dropping
1448	Open 16	M3, A9,16	L/R=3×10-4 and dropping (saturated at 4×10-5 in 5 mins)
1448	Close 16 and open 5	M3, A9,5	L/R= 2×10-6, P2=9.2×10-3
1450	Spraying around the traps	M3, A9,5	L/R= 1.2×10-6, P2=9.2×10-3
1450	Spraying around GHC connections	M3, A9,5	L/R= 1.0×10-6, P2=1.0×10-2
1452	Close 5	M3, A9	-
1454	-	M3, A9	L/R= 9.0×10-7, P2=5.0×10-3
1454	Open 16	M3, A9,16	P2 drops and L/R increases; L/R= 1.5×10-4, P2=4.8×10-3
1509	-	M3, A9,16	L/R=3.7×10-5P2=3×10-3
1509	Spray GHS, still lines and connections in/on GHS and Fridge and traps.	M3, A9,16	No change; L/R=3.7×10-5P2=3×10-3
1515	Close 16, close A9	M3	L/R=3.8×10-8, P2=2.4×10-3
1515	Open A9	M3, A9	L/R=1.5×10-5 and dropping (saturated at 8.9×10-7 in 5 mins)
1528	Close A9	M3	-
1535	Attatching Speedivalve (open) to auxillary trap 'from fridge' valve in GHC (CHECK NAME)	M3, speedivalve	-
1535	Open A9 and 16, pumping with leak detector	M3, speedivalve, A9, 16	L/R=2×10-5, P2=5×10-3
15--	Shut 16	M3, A9, speedivalve	L/R=2×10-6, P2=5×10-3
1554	Open 16	M3, A9, speedivalve, 16	L/R=3×10-5, P2=8×10-3
1556	-	M3, A9, 16	L/R=1.5×10-5, P2=3.8×10-3
1557	Close speedivalve	M3, A9, 16	No change; L/R=3×10-5, P2=8×10-3
1558	Open speedivalve	M3, A9, speedivalve, 16	No change; L/R=3×10-5, P2=8×10-3
1558	Close speedivalve	M3, A9, 16	-
1558	Close 16	M3, A9	-
1600	Open 16	M3, A9, 16	-
1614	-	-	L/R=8.07×10-7P2=2.3×10-3
1614	Open speedivalve	M3, A9, speedivalve, 16	-
1616	-	M3, A9, speedivalve, 16	L/R=1.6×10-4
1616	Close speedivalve	M3, A9,16	-
1634	Close A9, 16 and M3. Turn off leak detector	-	-
1635	Vent leak detector to air and allow turbo to slow.	-	-

Conclusions: Valve 15 has a slow leak.

Testing the still line and gas handling cabinet

The testing sequence was as follows:

Time HH:MM	Action	Open valves	Pressure _mbar.l/s_ (L/R), mbar (p2)
1151	Attach leak detector and open M3 and A9	M3, A9	L/R=5×10-6, P2=3.7×10-2
1200	Open 8, 2, 0 and leave leak detector to pump down	M3, A9, 8, 2, 0	L/R=2×10-2, P2=6.5×10-2
1225	-	M3, A9, 8, 2, 0	L/R=7.4×10-6, P2=9×10-3
1225	Spray around still line, near the cryostat	M3, A9, 8, 2, 0	L/R=7.1×10-6
122-	Spray T-bar on GHS	M3, A9, 8, 2, 0	L/R=5.8×10-6, P2=8.3×10-3
122-	Spray back of the turbo and connections	M3, A9, 8, 2, 0	L/R=5.0×10-6, P2=7.9×10-3
122-	Spray black vacuum manifold	M3, A9, 8, 2, 0	L/R=9.2×10-6, P2=7.5×10-3
1400	note: clamps lose on T-bar on GHS (clamp closest to front display)	M3, A9, 8, 2, 0	L/R=1.1×10-6, P2=3.3×10-3
14--	Sprayed T-bar on GHS again	M3, A9, 8, 2, 0	L/R=1.1×10-6, P2=3.3×10-3
14--	Sprayed still pumping line of fridge again	M3, A9, 8, 2, 0	L/R=1.1×10-6, P2=3.3×10-3
14--	Sparyed every connection in GHC	M3, A9, 8, 2, 0	L/R=1.1×10-6, P2=3.3×10-3
14--	Closed 0, 2, 8	M3, A9	L/R=1.1×10-6, P2=3.3×10-3
14--	Open 5 (quick testing of traps)	M3, A9, 5	L/R increases a littl
14--	Open 16 (quick testing of traps)	M3, A9, 5, 16	L/R increases massively L/R=7×10-3, P2=9.5×10-

Conclusions: The still and GHS appear to be leak-tight, however the traps may have a leak (see previous section).

Leak test on 2nd March 2011

Time	What	P2 ( mbar)	Pstill ( mbar)	L/R ( mbar.l/s)
1/2/2011: 1405	Tubo on, Open M3, A9, 8, 2, 0, 1, 6, 7, compressor bipass, gave valve	-	-	-
1445	Pturbo=4.5×10-4 mbar; Pstill=1.9×10-1 mbar. Run S1 ot pump faster (open S2)	-	-	-
1523	Pturbo=2.8×10-4 mbar; Pstill=5×10-4 mbar	-	-	-
2/2/2011: -	Pturbo=3.1×10-4 mbar; Pstill<5×10-5 mbar. Close S1 and S2	-	-	-
1130	close M3, A9, 0, 1, 2, 8 and stop turbo.	-	-	-
1134	start leak detector
1141	-	4.7×10-3	<5×10-5	5×10-10
1143	spray valves on top of leak detector (LD) and around M3 connection	3.8×10-3	<5×10-5	2.6×10-10
1143	open M3	-	-	-
1148		2.8×10-3	6.5×10-4	7.4×10-10
1150	spary around M3 connections	2.6×10-3	7.4×10-4	6.6×10-10
1150	open A9	-	-	-
1232	-	1.9×10-3	1.9×10-3	2.5×10-7
1239	spray around the back of of the gas cabinet	1.8×10-3	2.1×10-3	2.5×10-7
1239	open 8	-	-	-
1323	-	1.6×10-3	3.1×10-3	3.7/3.8×10-7
1340	-	1.6×10-3	3.4×10-3	3.8×10-7
1343	spray around back of gas cabinet	1.6×10-3	3.5×10-3	3.8×10-7
1344	open 2	1.6×10-3	3.5×10-3	3.8×10-7
1359	open 0	1.6×10-3	3.5×10-3	3.8×10-7
1400	open 1	-	-	-
1403	spray around still (on DR and gas cabinet), spray in gas cabinet.	1.8×10-3	3.9×10-3	3.8×10-7
1404	leak detector off, open gate valve, leak detector on	-	-	-
1455	-	1.6×10-3	8.5×10-3	9.9×10-7
1500	spray around still (on DR and gas cabinet), spray in gas cabinet.	1.6×10-3	8.5×10-3	9.8×10-7
1504	repeat the above	-	-	-
1505	-	1.6×10-3	8.5×10-3	9.9×10-3
1508	-	1.6×10-3	8.5×10-3	9.8×10-3
1508	-	1.6×10-3	8.5×10-3	9.8×10-7
1519	-	1.6×10-3	8.4×10-3	9.7×10-7
1543	spray around still (on DR and gas cabinet), spray in gas cabinet.	1.6×10-3	8.5×10-3	9.9×10-7
1648		1.6×10-3	9×10-3	9.9×10-7

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