Subatomic Physics Detectors
Basic high energy detector
Some Detector Requirements
Position resolution wanted
- Example Z events:
Two events are shown, one Z --> two electrons and one Z -->
two muons. Each event has a tracking view showing the charged
tracks in the bend plane (we call this the r-phi view for radius-azimuth)
of the the 1.4 Tesla CDF solenoid magnet. The diameter of the
circle is about 3 meters. The "lego" plot is also shown
for each event -- with "stacks" of electromagnetic (red)
and hadronic (blue) energy seen in the calorimeter towers. Think
of this "lego" plot as the surface of a cylinder around
the solenoid unwrapped into a plane. Note in the Z--> two muon
event the calorimeter energy scale is very small since the muons
penetrate the calorimeter and leave only "minimum ionizing"
pulse height. So we identify the muons from their charged tracks
and hits in the Muon Chambers represented by the square box drawn
outside of the 3 meter tracking circle. This box is not drawn
to scale -- in the experiment the box is about 10 meters by 10
meters. Look closely to see the "hits", drawn as x's
in line with nearly straight (therefore high momentum) tracks
in the circle. In the lego plot we have drawn vertical lines to
represent the energy of the muon tracks. Note the difference in
the Z --> ee event where there are straight tracks pointing
at clumps of red (electromagnetic) energy and no hits in the muon
- "GOLDEN" Top Event -
- This event has a 109 GeV e+, and 4 Jets of (1) 90,
(2) 77, (3) 64, and (4) 38 GeV. Jets (1) &
(4)are tagged as b-jets by the CDF Silicon Vertex Detector. Jets
(1,2,3) are from top; (2) & (3) are from a W. The event fit
gives a Top Quark Mass of 170 +- 10 GeV.
- CDF Central Detector:
In this closeup of the central part of the CDF detector one can
see various detector elements, as well as some of the cables and
electronics used to collect information from the parts of the
detector. The boxes mounted on the face of the orange structure
contain electronics. The black semicircles to the right and left
are the hadronic calorimeters. They detect particles known as
hadrons by causing the particle to collide many times with iron
plates. In these collisions, other particles are produced. These
particles cross sheets of scintillating plastic where they give
off small flashes of light. A measurement of the total amount
of light measures the energy of the hadron.
- CDF Forward Detectors :
The central detector represents about 1/3 of the total detector.
There are also two forward detectors; so named because they are
arranged along the main accelerator beam in front of and in back
of the central detector. In this photograph, one can see these
detectors in the assembly hall area outside the main machine before
they were installed.
- 3-Dimensional COLOR View of CDF
in Collider Run I, 1992-96
- Schematic COLOR Quarter Section
of most of CDF in Collider Run I, 1992-96: Highly
schematic CDF drawing designed for conference talks. Same view
as the above quarter section, but with more emphasis on the central
detector and tower geometry. Note that the position and size of
the forward calorimeter is not to scale.
- Quarter Section of CDF
in Collider Run I, 1992-1996: CDF
as configured during Collider Run I shown as one-quarter of an
elevation view. A plan view would look the same since the detector
is nearly symmetric when rotated about the Tevatron beam line.
Note the interaction point is in the lower left corner.