Comments and questions concerning E907
gas needs
Terry Tope
General system layout
- Bottles should go in existing gas shed outside MC8
- Will have to purchase new flammable gas detectors.
- New heater will be required.
- Will shed be accessible with beam on?
- May put mixers in MC8
- Would like to know if MC8 will be accessible with beam
on?
- Will discuss layout with Jim Priest.
- Distribution for individual chambers could be in experimental
area
- These panels would not typically need to be accessed with
beam on.
- Beam CKOV's should be monitored and controlled from
experimental control location
- Can use Magic mixer from E781
- Premix not practical due to small gas volume in bottles
resulting from Isobutane vapor pressure.
- Mixing system will require calibration, refurbishing, and
testing.
- Magic gas compositions?
- 1-4, 82% Argon, 15% Isobutane, 3% Methylal?
- 5-6, 75% Argon, 25% Isobutane, 0.15 Freon 13B1, 1%
Isopropyl?
- Will find out if Fermilab will allow the small amount of
Freon to be vented.
- Flow rates for magic gases and N2 purge?
- Gas purity concerns?
- Mix P10 online or buy premix (see attached cost
estimate)?
- Could use Xe/Methane mixer from E781.
- Purity requirements?
- Flow rates for P10 and N2 purge?
- Is some sort of canary needed?
- Use 90% P10 and 10% CF4?
- Flow rates for mixture and N2 purge?
- Could use existing 871 mixer set up for Isobutane/CF4 to mix
P10 and CF4.
- Use CO2?
- How pure must gas be?
- What pressure to be maintained?
- How large is the volume?
- May be able to use gas rack it used in E781.
- How often will gas be changed?
- How fast must a change occur?
- How much of previous gas must be removed (purity)?
- How much N2 flow to photomultiplier?
- How accurate must pressure be measured/maintained?
- What are the set pressures?
- How accurate must temperature be measured?
- Is the system such that gas goes in an inlet and must be
removed by a pump?
- Or can gas be flowed thru the device to increase purity using
volume changes?
Beamline chambers
- How many and what size?
- What gas mixture(s)?
- What flow rates?
- C4F10 issues
- It appears that other experiments were/are very concerned
about purity, typical systems had the following features
- Gas is recirculated and inline liquefaction is used to
separate out volatile components
- Often purity is monitored
- Large amounts of molecular sieves and activated carbon
- See attached list of C4F10
observations.