1 / 12

Micromegas TPC and wire TPC First measurements in a magnetic field

Micromegas TPC and wire TPC First measurements in a magnetic field. P. Colas 1 , Y. Giomataris 1 , J. Jeanjean 2 , V. Lepeltier 2 , J. Martin 1 , A. Olivier 1 1) DAPNIA Saclay 2) LAL Orsay.

nardo
Download Presentation

Micromegas TPC and wire TPC First measurements in a magnetic field

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. Micromegas TPC and wire TPCFirst measurements in a magnetic field P. Colas1, Y. Giomataris1, J. Jeanjean2, V. Lepeltier2, J. Martin1, A. Olivier1 1) DAPNIA Saclay 2) LAL Orsay • A small-gap wire chamber TPC and a Micromegas TPC (both 1cm drift) have been put in 1-2 Tesla magnetic field • Feedback has been measured and progress on simulation has been made. P. Colas - Micromegas and wire TPCs

  2. Experiment • We ran end of June with a small-gap TPC and a micromegas TPC • The primary ionization was provided by • an 55Fe source (25 MBq, gain typically 100,000) for the wire chamber • a 90Sr source (1 GBq, gain a few 100) for the micromegas • The currents from the supplies are monitored, allowing to measure the feedback. • Mainly the results from micromegas are shown here. • The results from the wire chamber are: no significant effect of the magnetic field, though simulation predicts an increase of 50% on the feedback from 0 to 2 T. To be understood. P. Colas - Micromegas and wire TPCs

  3. SETUP P. Colas - Micromegas and wire TPCs

  4. detector Ar:CH4 90:10 2T Magnet High voltage and monitoring P. Colas - Micromegas and wire TPCs

  5. Small-gap wire TPC Micromegas TPC 0 +2KV 0 - 300 V 0 -340 V - 640 V 55Fe 90Sr wires grid Cathode anode mesh Cathode 2mm 2mm 1cm 50 mm 1cm P. Colas - Micromegas and wire TPCs

  6. Feedback : theory and simulation • We (Jerôme Martin) carried out simulations with 2D geometry to: • Understand the feedback • look at the effect of the magnetic field : predicts 50% increase in the wire chamber, and no effect in micromegas • Ideally, the feedback is given by the inverse field ratio E(drift)/E(amplif) • It is less good (i.e. larger) if the dispersion in the avalanche is small with respect to the hole pitch • The two important quantities are s : the dispersion after 50 microns and • l, the pitch. The hole size does not matter when the field ratio is high P. Colas - Micromegas and wire TPCs

  7. Theoretical ion feedback Hypothesis on the avalanche Gaussian diffusion Periodical structure Avalanche Resolution l 2*sigma P. Colas - Micromegas and wire TPCs

  8. Theoretical ion feedback Calculations Sum of gaussian diffusions 2D 3D P. Colas - Micromegas and wire TPCs

  9. 500 lpi (sigma/l=0.25) 1000 lpi (sigma/l=0.5) 1500 lpi (sigma/l=0.75) Theoretical ion feedback Results P. Colas - Micromegas and wire TPCs

  10. Theoretical ion feedback P. Colas - Micromegas and wire TPCs

  11. P. Colas - Micromegas and wire TPCs

  12. P. Colas - Micromegas and wire TPCs

More Related