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The kaon beams travels into the vacuum tank, which contain the photon veto ring counters, regenerator and the lead mask. Notice how large the vacuum tank is. That stairway in the far right of this picture leads to back to the vacuum decay pipe, the final sweeper and the defining collimator. The kaon beams are decaying in a very high vacuum. |
| Upstream View of the Vacuum Tubes
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| The Regenerator | The Mask
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There are four photon veto ring counters located on the vacuum tank. The purpose of these ring counters are to reject any photons ( g) escaping the downstream electromagnetic calorimeter. |
| The Veto Ring Counters |
| Vacuum pumps are located along the vacuum chambers. Each pump pumps at 18 000 liters per second. This creates a very tight vacuum inside the chambers! |  |
| The Vacuum Pump
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| The Vacuum Window | |
At the end of the vacuum chambers is a 1.8 meter in diameter window. This window, called the Vacuum Window, is comprised of Kevlar and Mylar.
Kevlar is one of the most important manmade organic fiber ever developed. You can find Kevlar in bullet proof vests worn by policemen.
The Kevlar provides the very highly tensile strength to density ratio and provides minimal elongation.
The aluminized Mylar reduces the water wapor permeation rate.
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You are probably
wondering, what does it look like inside the vacuum
chambers? Well, here is your opportunity to view what is
inside those large vacuum chambers. Inside the vacuum chambers, they are very smooth and are painted an epoxy vacuum white paint. The reason for this, is to give better results and measurements of the kaon decays as it travels down the vacuum chamber. As the kaon beams travels through the vacuum vessel, the beams are decaying into many different particles. The physicists need to be able to identify these decays. |
| With the Vacuum Window
Removed
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| You can see that the two
kaon beams travel in the middle of the vacuum chamber.
The instrument shown is called a Z calibrator. It made from a tungsten metal. It is a counter for the kaon particle decay. It will allow the physicists to reconstruct the positions of the kaon decay. It is very important for the calibration to be correct. They are working with very small particles and the ablity to identify the decay is important to this project. |
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| The Z Calibrator
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The dragon is nothing
more that a safety device. Once the KTeV project is in
action, the dragon is place in front of the vacuum
window. If the window breaks, the dragon will serve as a shield from the vacuum. It will close up the window and thus reducing any damage. Remember each vacuum pump diffuses 18 000 liters per second. That is a very high vacuum rate! |
| The Dragon |
