gas studies with mdt @ h8 water contamination and series effect flow rate effects changes in co2...

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 ?