1 / 16

Straw tube measurements

Straw tube measurements. Sebastian Bablok, Øystein Djuvsland, Per Thomas Hille. The Detector. A model of the straw tube detector used for the Outer Tracker in LHCb 16 channels 1500 V bias Gas mixture: 75% Ar, 15% CH 4 , 10% CO 2. The straw tube. Cathode tube, (5 mm Ø). 1500 V.

niran
Télécharger la présentation

Straw tube measurements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Straw tube measurements Sebastian Bablok, Øystein Djuvsland, Per Thomas Hille

  2. The Detector • A model of the straw tube detector used for the Outer Tracker in LHCb • 16 channels • 1500 V bias • Gas mixture: 75% Ar, 15% CH4, 10% CO2

  3. The straw tube Cathode tube, (5 mm Ø) 1500 V Anode wire, Au-plated tungsten (0,025mm Ø) Gas: 75 % Ar 15 % CH4 10 % CO2

  4. Testing • Test setup for testing the 16 channels one by one • “Only” 2 dead channels 15 8 0 Nice soldering points!

  5. The Final setup

  6. Scope trace (average) of output voltage from straw tube 15.

  7. Hypotesis • The gas amplification gain depends on the bias voltage of the straw tubes. • The gain increases at higher voltages

  8. Test of hypotesis • Measure the output signal from the straw tubes for different values of the HV.

  9. Results

  10. Conclusion (preliminary) • Our observations contradicts the Hypotesis. The gain is independent of the bias voltage.

  11. Discussion • We dont believe in these results, gain shoud depend on HV. • Implication: We need an ad-hoch hypotesis • Ad hock hypotesis: We used wrong type of radioactive source (strontium). • We should repeat the measurements again with a monocromatic source (Fe55).

  12. The output voltage of the straw tubes was measured for 1350, 1400, 1450, 1500, 1550 Volt. At 1550 V we could also se the escape peak. 1350 V 1350 V New Gain measurements 1400 V 1400 V 1450 V 1450 V 1500 V 1500 V 1550 V 1550 V

  13. Escape peak, enlarged view

  14. Results All measuremnts fitted with an exponential Function. Only the 4 highest measuremts fitted with an exponential Function.

  15. Conclusion • The output signal from the straw tubes depends on the bias voltage. • The dependence is exponential between 1400 and 1550 Volt

  16. Noise measurement • We measured the number of fake trigger as a function of the trigger treshold. • Without radioactive (upper figure). • With radioactove source (bottom figure). The source was sentered abowe straw 8

More Related