1 / 9

Detectors

Detectors. Measuring Ions. A beam of charged particles will ionize gas. Particle energy E Chamber area A An applied field will cause ions and electrons to separate and move to charged plates. Applied voltage V Measured current I. I. +. E. A. -. V. Cylindrical Chamber.

lilith
Download Presentation

Detectors

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. Detectors

  2. Measuring Ions • A beam of charged particles will ionize gas. • Particle energy E • Chamber area A • An applied field will cause ions and electrons to separate and move to charged plates. • Applied voltage V • Measured current I I + E A - V

  3. Cylindrical Chamber • Cylindrical geometry is common for counters. • Grounded outer cathode • High voltage anode • The avalanche is limited to a region near the wire. I + - V

  4. A single track in a chamber creates many avalanches. All contribute to one pulse Timing is based on first avalanche arrival. Usually nearest point in the field Single Track

  5. An array of proportional readout wires can be placed in an array. Invented in 1968 by Georges Charpak Used in many discoveries Received the 1992 Nobel Prize Provides excellent position resolution for charged particle tracks. Multiwire Proportional Chamber

  6. Liquid noble gases can be used in ionization chambers. Liquid argon, krypton, xenon Uranium plates are alternated with readout pads. Separated by liquid argon Readout on printed circuit boards. Outer readout pads Inner layer readout wires Ground planes to reduce crosstalk Uranium Cell 4.0 mm 2.3 mm 4.3 mm incident particle depleted uranium readout pad liquid Ar gaps

  7. Scintillation detectors rely on the emission of photons from excited states. Counters Calorimeters An incident photon or particle ionizes the medium. Ionized electrons slow down causing excitation. Excited states immediately emit light. Emitted photons strike a light-sensitive surface. Electrons from the surface are amplified. A pulse of electric current is measured. Scintillation Detector

  8. Photomultiplier Tube • A photomultiplier tube (phototube, PMT) combines a photocathode and series of dynodes. • The high voltage is divided between the dynodes. • Output current is measured at the anode. • Sometimes at the last dynode

  9. Multiple detectors are used to identify different particles. Tracking chambers to measure position. Calorimeters to measure energy. Muon from top decay Multipart Detector

More Related