gas studies with mdt @ h8 water contamination and series effect flow rate effects changes in co2...
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Gas Studies with MDT @ H8
Water Contamination and Series Effect
Flow rate effects
Changes in CO2 percentage
Air Contamination (2001 measurements)
Water contamination (P. Bagnaia, C. Bini, F. Cerutti, S. Fiore, L.P., E. Solfaroli, )
Only 2 “good points” : 2700 ppm, 500 ppm
Data Analized only with spectra
Tmax variations up to 200 ns
tmax/ (100 ppm H2O) = 6-7 ns
Same dependance found in the
Series Effect, (assuming water to be
the cause) Max effect +-7 ns
(BILPV)
Agreement with Garfield calculation
To be completed: Variation of the RT-relations vs
H2O
To be done: Variation of the Resolution
Variation of the efficiency.
Water 2700, 500 ppm
500 ppm2700 ppm
Time ns Time ns
Space mm Space mm
Tracking with BML and BOL and extrapolating to BIL
Difference RT (500-3000)
Difference mm
Time ns
RT difference at equal timesA better comparison should be at equal space …… Next step
Garfield calculation on H2O
Drift time at 14 mm as a function of the H2O content
6-7 ns/100 ppm
Alignment
From the difference of the right and left branch of the rt relation we get thetwice the displacement of multilayer w.r.t. the other chambers
ML position mm
Gas Series Effect
BIL PV
1 2 3
RO side
Direct water measurement on BIL RM and BILPV & Bundle
Calibration @ 3 Bar
The Water contamination decreases after flushing nitrogen in the
FC
It seems that the water gets in from O-rings/end plugs/ jumpers.
Measurement on Bundle to be redone next week
Bundle
Flow rate effects
Example of time dependence (b) BOL6/1 (l=1)
+4 h
+22 h
+35 h
+77 h
Flow dependance (T1-T3)
20 l/h after 77 h
33 l/h 63 l/h
Chamber with closed Gas
Maximum drift time increases with time (as expected if due to an increase of water)
Dependance on CO2 %
Data taken with 6%, 6.5%, 7.5%, 8% of CO2
Only BILRM and BIL PV with “new gas”
To be completed : Study the differences in RT-relation
To be done : Effects on the Resolution
Effects on the efficiency
CO2 results
Tmax for all the BILs tubes
71 ns/(%CO2)
Tmax vs %CO2
Data Taken at high Flow600-150 nl/h (Atlas Flow 60 NL/h)
RT-relation studies with different CO2 %Tracking using BML and BOL enable to directly measure the RT-relation on BIL. Using this technique it is possible to measure the differences on the RT-relation , Multilayer position, resolution and efficiency.
Time ns Time ns
Space mm Space mm
Difference RT 6%-8% CO2
Difference mm
Time ns
Multilayers Position
Difference between the two branches of RT relation for the 2 MLayers
Air Contamination (F.Cerutti)Data taken in 2001
“Lab AIR” = 80% N2, 20% O2
Air Contamination: 0.5%, 0.3%, 0.1% 0.05%
O2 contents (ppm):1000, 600, 200, 100
Measured : Change in RT relation in Resolution and
in efficiency.
Comparison with Garfield only in qualitative agreement
with data
RT-Relations
Differences up to 200m
Contaminated gas faster
<v>(No air-5 per mill)~3%
Differences up to 200m
Contaminated gas faster
<v>(No air-5 per mill)~3%
Resolution
Deterioration of the resolution >1 per mill
contamination
Average resolution:
• No air 113 m
• 1 per mill 125 m
• 3 per mill 141 m
• 5 per mill 158 m
Deterioration of the resolution >1 per mill
contamination
Average resolution:
• No air 113 m
• 1 per mill 125 m
• 3 per mill 141 m
• 5 per mill 158 m
3 Efficiency
Plateau efficiency ~96%
Inefficiency due to -ray
Significant difference only for 5 per mill at the end of the tube: attachment ?
Plateau efficiency ~96%
Inefficiency due to -ray
Significant difference only for 5 per mill at the end of the tube: attachment ?
Hit Efficiency
Plateau efficiency ~100%
Inefficiency only close to the tube
Significant difference only for 5 per mill at the end of the tube: attachment ?
Plateau efficiency ~100%
Inefficiency only close to the tube
Significant difference only for 5 per mill at the end of the tube: attachment ?