Editing Ring-imaging Cherenkov detector (section)

=== RICH Types ===

[[File:RICH two types02 2013-03-15.svg|thumb|right|upright|Fig.7: focusing and proximity-imaging RICH designs]]
Both focusing and proximity-focusing detectors are in use (Fig.7). In a focusing RICH detector, the photons are collected by a spherical mirror with focal length <math>f</math> and focused onto the photon detector placed at the focal plane. The result is a circle with a radius <math>r = f\theta_c</math>, independent of the emission point along the particle's track (<math>\theta_c \ll 1</math>). This scheme is suitable for low refractive index radiators (i.e., gases) with their larger radiator length needed to create enough photons.

In the more compact proximity-focusing design a thin radiator volume emits a cone of Cherenkov light which traverses a small distance, the proximity gap, and is detected on the photon detector plane. The image is a ring of light the radius of which is defined by the Cherenkov emission angle and the proximity gap. The ring thickness is mainly determined by the thickness of the radiator. An example of a proximity gap RICH detector is the High Momentum Particle Identification ([http://alice-hmpid.web.cern.ch HMPID]), one of the detectors of ALICE ([[A Large Ion Collider Experiment]]), which is one of the five experiments at the LHC ([[Large Hadron Collider]]) at [[CERN]].

[[File:DIRC Schema01 2013-03-15.svg|thumb|upright=2.0|left|Fig.8: DIRC detector]]
In a [[DIRC (detector)|DIRC]] (Detection of Internally Reflected Cherenkov light, Fig.8), another design of a RICH detector, light that is captured by total internal reflection inside the solid radiator reaches the light sensors at the detector perimeter, the precise rectangular cross section of the radiator preserving the angular information of the Cherenkov light cone. One example is the DIRC of the [[BaBar]] experiment at [[SLAC]].

[[File:Lhcbview.jpg|thumb|upright=2.0|right|Fig.9: LHCb detector]]
The [[LHCb]] experiment on the Large Hadron Collider, Fig.9, uses two RICH detectors for differentiating between [[pion]]s and [[kaon]]s.<ref>{{cite journal |last1=Alves |first1=A. A. Jr. |collaboration=LHCb Collaboration |title=The LHCb Detector at the LHC |journal=Journal of Instrumentation |date=2008 |volume=3 |issue=8 |pages=S08005 |doi=10.1088/1748-0221/3/08/S08005|bibcode=2008JInst...3S8005L |hdl=10251/54510 |s2cid=250673998 |url=https://www.zora.uzh.ch/id/eprint/15788/9/jinst8_08_s08005V.pdf |hdl-access=free }}</ref> The first (RICH-1) is located immediately after the Vertex Locator (VELO) around the interaction point and is optimised for low-momentum particles and the second (RICH-2) is located after the [[magnet]] and particle-tracker layers and optimised for higher-momentum particles.<ref name="Adinolfi"/>

[[File:Alpha Magnetic Spectrometer - 02.jpg|thumb|upright=1.5|left|Fig.10: AMS-02]]
The [[Alpha Magnetic Spectrometer]] device AMS-02, Fig.10, recently mounted on the [[International Space Station]] uses a RICH detector in combination with other devices to analyze [[cosmic rays]].