Control of the attributes of data from the muon system, namely:
MDT ( 7.3.1 Monitored Drift Tubes (MDT)) : Monitored Drift Tubes
CSC ( 7.3.2 Cathode Strip Chambers (CSC)) : Cathode Strip Chambers
RPC ( 7.3.3 Resistive Plate Chambers (RPC)) : Resistive Plate Chambers
TGC ( 7.3.4 Thin Gap Chambers (TGC)) : Thin Gap Chambers
SMTr ( 7.3.5 Simulated Muon Tracks (SMTr)) : Simulated Muon Tracks
Segment ( 7.3.6 Segments of Muon Tracks (Segment)) : Segments of Muon Tracks
Track ( 7.3.7 Reconstructed Muon Tracks (Track)) : Reconstructed Track Collections
MuonROI ( 7.3.8 Muon Region of Interest (MuonROI)) : Muon Region of Interest
The MDT's provide precision tracking of muons, bending in the toroidal magnetic field, over a cylindrical region of 11m in radius and 23 m in half-length. Each MDT is a straw with a diameter of 3 cm and a length in the range from 70 to 630 cm. The drift radius within each straw is measured with a precision of ≈80µm. The straws are grouped in modules which are rectangular in the barrel region and trapezoidal in the endcap regions. The modules are arranged in three radial stations in the barrel and three axial stations in the endcaps, and 16 sectors in azimuth. Within each module the straws are arranged in two groups of multi-layers, with four straws in each multi-layer in the inner station and three straws in each multi-layer in the middle and outer stations.
Viewing MDT Data
Within each sector, straws are aligned perpendicular to the radial line joining the nominal origin to the center of that sector. The data from the MDT straws are best viewed in the X'/Z projection ( 5.7 X'/Z Projection) by selecting the azimuthal angle of its corresponding sector by switching on the MDT Sector mode and selecting the appropriate sector number. Sector number 0 is at 3 o'clock and the sector numbers increase in a counter-clockwise direction. The selected sector is shown on the top half of the picture and the geometrically opposite sector is shown on the bottom half. The MDT hits are normally viewed as circles but they can be drawn as lines by selecting the appropriate mode. In the X'/Z projection ( 5.7 X'/Z Projection) the MDT hits may be compared directly to the tracks measured in the muon system.
In the ρ/Z projection ( 5.4 ρ/Z Projection) the MDT data are represented in an approximate way, essentially the X'/Z projection of all 16 MDT sectors are drawn superimposed, with 8 in the top half of the picture and 8 in the bottom. In this way one can easily see the data from all 16 sectors in the same picture. However ρ is only approximated for these MDT hits which can therefore only be approximately compared to tracks measured in the muon system which are still drawn with their true ρ.
Graphical Representation
The color of each hit is defined by the color function which may be either
constant, in which case the constant color is used for all hits,
or it may vary with each hit being given the color of its associated
simulated track, the colors of unconnected and shared hits can be selected,
reconstructed track, the colors of unconnected and shared hits can be selected,
subdetector (Endcap-,Barrel,Endcap+).
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.
The CSC's are used to provide precision coordinates in the extreme endcap regions (η>1.9) where MDT's ( 7.3.1 Monitored Drift Tubes (MDT)) can't be used. They are multiwire proportional chambers with cathode strip readout. The precision coordinaate is obtained by measuring the charge induced on a segmented cathode by the avalanche produced on an anode wire. The cathode strips for the precision measurement are oriented orthogonal to the anode wires. High precision is obtained by charge interpolation between neighbouring strips on the segmented cathode. The anode wire pitch is 2.54 mm and the cathode readout pitch is 5.08 mm. The precision coordinate is measured from a cluster of neighbouring strips with a resolution of around 60 µm. A second orthogonal coordinate is measured with less precision from cathode strips oriented parallel to the anode wires (this coordinaate is not yet available in Atlantis). The resolution of the precision coordinaate measurement is sensitive to the Lorentz angle and the chambers are therefore oriented so that high momentum tracks originating from the interaction enter at normal incidence. CSC's are arranged in two layers of modules each of which provides four coordinate measurements.
Viewing CSC strips and clusters
The precision cathode strips are aligned parallel to the MDT ( 7.3.1 Monitored Drift Tubes (MDT)) straws and may be best viewed together with them in the X'/Z ( 5.7 X'/Z Projection) and ρ/Z projections ( 5.4 ρ/Z Projection). The user may select data from the strips, the clusters formed from the strips or both. The strips are represented as a histogram of the measured charge. The clusters are respresented by a line corresponding to the one standard deviation uncertainty on the position measurement.
Graphical Representation
The color of each strip is defined by the strip color.
The color of each cluster is defined by the color function which may be either
constant, in which case the constant color is used for all hits,
or it may vary with each hit being given the color of its associated
simulated track, the colors of unconnected and shared hits can be selected,
reconstructed track, the colors of unconnected and shared hits can be selected,
subdetector (Endcap-,Endcap+).
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.
The RPC's are mainly used to provide a muon trigger but they also provide a second coordinate measurement orthogonal to those from the MDT's ( 7.3.1 Monitored Drift Tubes (MDT)). The RPC's are present only in the barrel region, in the endcap regions the same role is performed by the TGC's ( 7.3.4 Thin Gap Chambers (TGC)). Each RPC module consists of two rectangular chambers. Each of these chambers are read out by an orthogonal series of pick-up strips. The η-strips are parallel to the MDT straws and the φ-strips are orthogonal to the MDT straws. The strip pitch varies between 3 and 4 cm. Two RPC modules are arranged on the inner and outer faces of each MDT module in the middle station and a third is positioned on either the inner or outer face of each MDT module in the outer station.
Viewing RPC strips
The η-strips are aligned parallel to the MDT ( 7.3.1 Monitored Drift Tubes (MDT)) straws and may be best viewed together with them in the X'/Z ( 5.7 X'/Z Projection) and ρ/Z projections ( 5.4 ρ/Z Projection). The φ-strips may be best viewed in the Y/X ( 5.1 Y/X Projection) and φ/ρ ( 5.5 φ/ρ Projection) projections.
R3D: RPC space points
From pairs of orthogonal strips belonging to the same RPC chamber a small 3D box may be formed. These R3D hits, which are currently constructed internally in Atlantis from the RPC strips, may be viewed in any projection. The formation of these R3D hits from there corresponding strips is best visualised in the RPC View's of the φ/Z projection ( 5.6 φ/Z Projection).
Graphical Representation
The color of each hit is defined by the color function which may be either
constant, in which case the constant color is used for all hits,
or it may vary with each hit being given the color of its associated
simulated track, the colors of unconnected and shared hits can be selected,
reconstructed track, the colors of unconnected and shared hits can be selected,
or each hit may be given a color which indicates whether it is part of an R3D space point
is3D.
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.
The TGC's are present only in the endcap regions, in the barrel region the same role is performed by the RPC's ( 7.3.3 Resistive Plate Chambers (RPC)). The TGC's are mainly used to provide a muon trigger but they also provide a second coordinate measurement orthogonal to those from the MDT's ( 7.3.1 Monitored Drift Tubes (MDT)). TGC modules are constructed from either doublets or triplets of chambers. There is a doublet module in the inner station which is used only to provide the second coordinate measurement. There are two doublet modules and one triplet module in the middle station which are used to provide both the trigger and second coordinate measurement. Each chamber consists of orthogonal sets of anode wires and cathode readout strips. The anode wires are parallel to the MDT straws and the cathode strips are orthogonal to both the MDT straws and the beam axis. The anode wires are read out in groups leading to an effective pitch between 0.7 and 3.6 cm. The cathode strip pitch is ?.? cm.
Viewing TGC strips and wires
The anode wires are aligned parallel to the MDT ( 7.3.1 Monitored Drift Tubes (MDT)) straws and may be best viewed together with them in the X'/Z ( 5.7 X'/Z Projection) and ρ/Z ( 5.4 ρ/Z Projection) projections. The cathode strips may be best viewed in the φ/Z ( 5.6 φ/Z Projection) projection.
T3D: TGC space points
From pairs of orthogonal strips and wires belonging to the same TGC chamber a small 3D box may be formed. These T3D hits, which are currently constructed internally in Atlantis from the TGC data, may be viewed in any projection. The formation of these T3D hits from their corresponding strips and wires is best visualised in the TGC View's of the Y/X projection ( 5.1 Y/X Projection).
Graphical Representation
The color of each hit is defined by the color function which may be either
constant, in which case the constant color is used for all hits,
or it may vary with each hit being given the color of its associated
simulated track, the colors of unconnected and shared hits can be selected,
reconstructed track, the colors of unconnected and shared hits can be selected,
subdetector (Endcap-,Endcap+),
or each hit may be given a color which indicates whether it is part of an T3D space point
is3D.
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.
Simulated muon tracks from the Monte Carlo truth information. The paths of these tracks may pass through material and regions of non-uniform magnetic fields. They are stored a three dimensional polyline, with a high density of points in the region of active MDT ( 7.3.1 Monitored Drift Tubes (MDT)), RPC ( 7.3.3 Resistive Plate Chambers (RPC)) and TGC detectors ( 7.3.4 Thin Gap Chambers (TGC)), and a lower density of points elsewhere.
The color of each simulated track is defined by the color function which may be either
constant, in which case the constant color is used for all tracks,
or it may vary with each track being given the color of its
index: in the range 0 to numSMTr-1,
identifier.
Track images are easier recognised if tracks get a black frame with a small frame width, especially in the V-plot if calorimeters are displayed as well.
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.
Muon tracks reconstructed by the MOORE package. The paths of these tracks may pass through material and regions of non-uniform magnetic fields. They are stored as a three dimensional polyline, with a high density of points in the region of active MDT ( 7.3.1 Monitored Drift Tubes (MDT)), RPC ( 7.3.3 Resistive Plate Chambers (RPC)) and TGC detectors ( 7.3.4 Thin Gap Chambers (TGC)), and a lower density of points elsewhere.
The color of each reconstructed track is defined by the color function which may be either
constant, in which case the constant color is used for all tracks,
or it may vary with each track being given the color of its
index: in the range 0 to numMTr-1,
identifier.
Track images are easier recognised if tracks get a black frame with a small frame width, especially in the V-plot if calorimeters are displayed as well.
More information about colors in Atlantis is given in 7.6.1 About the Use of Colors.