[Dsg-mvt] MVT MFC Heaters

[Marc McMullen]

Bob,

We will monitor the enclosure temperature overnight, you may want to 
make an adjustment to the enclosure temperature control we have seen it 
peak at 54F and then drop to below 46F before the cycle started again.

We spoke with Steve Rockwood from MKS, he says there may be issues with 
the Viton seals, and suggests using Kalrez as a possible alternative. We 
are waiting for his final suggestion/report.

Once Todd has the CF4 hooked up we can test that MFC. As far as the 
C4F10 MFC, the operating range is 10C - 50C, anything outside of that 
and the unit will not perform to spec. We have seen that with the DC 
MFCs when the temperature in the Gas Shed dropped below 50F.

The gas vapor pressure is specified to be 30psi @ 70F. Until we can get 
the system stable to these numbers, we risk the operation of the MFC.

Marc


On 1/2/2018 2:17 PM, Bob Miller wrote:
> Hey Marc and Brian,
>
> Todd is working on the heaters and insulation for the MFCs.  The heat 
> tape was limited to 5% by George.  Todd has increased it to 20% and 
> will monitor the inside temperature and adjust the heaters as 
> necessary.  The heaters will turn off when the thermostat reaches 
> temperature anyway.  The heat tape is rated at 144 watts, so I am sure 
> it will be able to heat the MFCs.
>
> Todd will also connect the CF4 bottle.
>
> Regards,
>
> Bob
>

-- 
Marc McMullen
Detector Support Group
757-269-7738