[Dsg-dc] DC Gas Mixing

[Marc McMullen]

DSG held a training session with Hall B Mechanical this morning. The 
topic was calibrating the DC gas mixture to the 10% CO2/ 90% Ar premixed 
standard.

The premixed gas standard is used as the direct reference for the 
current value (in mA) of the gas mixture; 10% CO2/ 90% Ar.

Today's training was done only using Mix 1, as it has the only working 
thermal conductivity gas analyzer. All measurements were taken using the 
Mix 1 analyzer.

The gas standard and mix values are very close (~8.4mA, ~2.74V), 
however, the sample coming from the buffer tank (R1 MFC output) 
indicates a higher CO2%.

Monday Hall B Mechanical will be able to connect the Mix 2 gas sample 
line to the manifold which is connected to Mix 1 analyzer. At that time 
we will isolate and zero all mixing MFCs and run the calibration tests 
on both mixing systems. After both mixing systems have been calibrated

Hall B management should consider purchasing a replacement for the CLAS 
6 (purchased mid 90s, last calibrated in 2000) analyzers for both mixing 
units (starting at $3700 per unit), and additional units for the output 
of the tanks.

The results of the analysis were as follows:

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

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