11.15 See attachment 1 for overnight EPICS log of TUDA2.CG5
Downstream flange *not* secured by four bolts
Current pressure 0.97Torr - rate of increase ~0.2 Torr/5h
This history is very similar to the previous test (with
the flange secured by four bolts)
- see https://elog.triumf.ca/Tuda/S1287/10
Conclude - leak-in rate not affected by (i) lack of bolts
securing downstream flange, (ii) addition of cabling within
TUDA chamber - provided that the TUDA chamber has previously
been pumped to 'good' vacuum (< 1E-05Torr, say).
16.40 Modified preamp services cabling to avoid unterminated test -
input to PD preamp which causes reflections to previous test -
inputs to the S2 preamps.
+/-15V PSUs
#1 +15V/0.25A -15V/0.1A (1x 16ch PD preamp + 1x MSL type W preamp - not installed)
#2 +15V/1.5A -15V/0.55A (2x MSL type S2 + 1x 16ch PD preamp units)
16.51 Time to 250mTorr ~14m
Time from 250mTorr to 4.75E-05Torr ~40m
See attachment 2
17.50 FTS RS44 set point +5.5 deg C
18.48 TUDA2.PNG5 7.8E-06Torr
FTS RS44 set point +21 deg C
Cryo pump gate valve closed
Turbo pump off
Four bolts securing downstream flange removed
Vent to c. 300mbar with *He*
N.B. TUDA2.CG5 reads 770 Torr with 300mBar of He in TUDA chamber
MKS Baratron (capacitance manometer - gas independent reading)
attached to manual vent port of the Varian V550 turbo pump
Pressure reading at 'good' vacuum 0.0 Torr - no offset
Bourdon MKS S2 preamp
Baratron Thermocouple
(mBar) (Torr) (deg C)
19.08 300 221.7
19.18 300 222.0 +19
19.28 300 222.1 +20
19.38 300 222.3 +20
19.48 300 222.4 +21
20.08 300 222.6 +21 |