Central Tracking System Calorimeter Muon System
This set of web pages explains the artifacts (detector prototypes, models and mockups) you can see in the DZero exhibit area, adjacent to the DZero Control Room in the DZero Assembly Building at Fermilab. You can find the text that goes with a particular piece by looking at its name (on a card next to it) which tells you which sub detector it belongs to, and then going to the web page for that sub detector.
You can also use its exhibit number (circled on the card next to the piece) and locate the same number on these web pages.
Examples of cards
The D0 experiment is one of two large general purpose particle physics detectors that were operating at the 2 Teraelectronvolt (TEV) Tevatron accelerator ring at Fermi National Accelerator Laboratory. DZero was built between 1985 and 1991 (with a major overhaul from 1996 - 2001), and was in operation from 1992 until 2012. DZero takes its name from its location on the ring, in section D0.
Fermi National Accelerator Laboratory is located about forty miles west of Chicago. It comprises some 5,800 acres of mostly undeveloped land and provides a home to many plant and animal species in a natural environment.
Physicists use the
DZero detector to study the array of particles and forces in nature by recording data
about collisions of protons and anti-protons in the center of the detector. Beams of protons and antiprotons circulate in the Tevatron accelerator and collide head-on at the center of D0 at nearly the speed of light, creating other particles that in turn decay into more stable particles. This volatile process replicates the conditions just after the big bang. The beams cross paths in the detector an average of 1.7 million times per second. When they cross, one or several pairs of protons and antiprotons can collide. Given the large kinetic energy from the collision, new particles that are more massive than the protons and antiprotons involved in the collision can be created. For interesting events, the detector records information necessary to evaluate the energy, momentum and electric charge of the emerging particles.
The detector performed very well during Run I of the Tevatron, 1992–1996, leading to the discovery of the top quark and measurement of its mass, a precision measurement of the mass of the W boson, detailed analysis of gauge boson couplings, studies of jet production, and greatly improved limits on the production of new phenomena beyond the standard model of particle physics, such as leptoquarks and supersymmetric particles, among many other accomplishments. After a major upgrade of the experiment, during which many components were replaced, the Tevatron Run II began March 1st 2001 and was scheduled to last through mid - 2009. By May 2003, the Run II integrated luminosity recorded by the D0 detector had surpassed the total luminosity recorded in Run I. The Tevatron eventually ran until 30 September 2011. Beyond the discovery of the top quark, the Tevatron legacy consists of precision measurements of parameters of the standard model, confirming and extending its range of validity, searches that exclude new particles and theories over a large range of parameter space, and eventually establishing '3 sigma' evidence for the long-sought Higgs boson, which was discovered (discovery customarily implies a '5 sigma' significance above a possible statistical fluctuation from background) in 2012 by the then 7 (now 13) TeV LHC at CERN.
While its companion detector, CDF, has been dismantled, DZero is being preserved -at least for the time being- as an exhibit. Since the end of operations, more than 3500 visitors have been able to view the detector (status August 2015).
Update: In Spring 2016 we added the complete CDF Run II Silicon Tracker to our exhibit! Having a complete collider silicon tracker nicely complements the silicon detector disks, ladders and prototypes we already have on display. The DZero silicon tracker still rests safely at the center of the DZero detector inside the collision hall.
Snapshot of a collision. This event display from the D0 detector shows the outcome of an interesting collision of a proton and an antiproton at Fermilab's Tevatron. The curved red paths mark the trajectories of charged particles recorded in the detector's central tracker. The colored bars indicate particle energies deposited in the detector's calorimeter. The blue disks correspond to part of D0's physical structure (the ICD detector), and are shown solely to give an idea of the location of objects relative to the central/forward detector boundary.
D0 Control Room
The D0 experiment uses many different technologies to detect particles and measure their properties. For this it employs several sub-detectors: closest to the point of collision, the tracker consists of a silicon and a scintillating fiber detector. Tracking detectors are typically very low in mass to reduce the scattering of particles, and are most often used in conjunction with a magnet that bends the trajectories of charged particles. These tracking sub-detectors are surrounded by a calorimeter, which is very dense and heavy -the DZero calorimeter is primarily made of uranium and liquid argon-, and finally by a system of wire chambers and scintillator panels designed to measure muons. The D0 detector measures about 30' × 30' × 50' and weighs about 5,500 tons.
Video of the DZero detector rolling into the collision hall: http://vmsstreamer1.fnal.gov/VMS_Site_02/VMS/Dzero_Roll_In_2001/index.htm
- 1st and innermost layer - The Central Tracking System made up of tracking detectors and a superconducting coil which produces a strong magnetic field - charged particles leave traces that allow researchers to map their flight path, which is bent by the magnetic field - DZero records this information with a series of silicon detectors nestled inside scintillating fiber detectors, both mounted on lightweight but very sturdy carbon fiber supports.
- 2nd layer - consists of calorimeters, which measure the energy of showers of particles by completely absorbing them; DZero uses a set of precise calorimeters filled with liquid argon as the active medium.
- 3rd layer - outer shell - The Muon Detector, which itself consists of three layers. These detectors catch the signals of muons that escape the inner layers of the detector.
The other pages of this web site contain more information on the parts of the DZero detector that are shown in the DZero exhibit.
When the Tevatron shut down on Sept. 30, 2011, scientists first stopped data-taking in the the CDF and DZero detectors. They stopped the data acquisition systems and turned off the high voltage to various subdetector systems. Then Helen Edwards, who was a lead scientist for the construction of the Tevatron in the 1980s, terminated the final store in the Tevatron by pressing a button that activated a set of magnets that steered the beam into the beam dump. Edwards then pushed a second button to power off the magnets that guided beams through the Tevatron ring for 28 years. For about a week following the shutdown, accelerator operations worked to warm up the superconducting magnets, normally kept at 4.8 Kelvin. Once the magnets reached room temperature, crews began removing the Tevatron's cooling fluids and gases.
It took about a month to fully shut down the CDF detector, including time to remove its cooling fluids and gases. Shutting down the DZero detector took longer, since the collaboration took data using cosmic rays as a way to double-check the calibration of its detector. The DZero detector was completely shut down after about three months, in early 2012.
Pictures showing the construction of the DZero collision hall (21)
The D0 collaboration consisted of researchers from about 90 institutions in 18
countries. D0 members came from the world’s leading universities and
laboratories. The collaboration consisted of about 540 members, including about
130 graduate students and about 100 postdoctoral researchers. The collaboration
membership is split nearly evenly between U.S. participants and those from
foreign laboratories and universities.