Tracking Group

  Primary Collimator Live Page

  Tony's Status Report

  Klaus's Status Report
  Michael's Status Report
  Yongguang's Status Report
  Jim's Status Report



  Tony's Plots 1
  Tony's Plots 2



  Qweak Simulation Forum

  Keep Out Zones a la Allena

  Previous Reports

           Collimator working group

Figure 1 - A picture of the collimator region with dimensions.

The above picture is a scaled drawing of the collimator region, with dimensions. In parentheses I have included the center of each element in z along with the total length in z. The vertical lines are the "detectors" used in the simulation and the centers are given (each is .5cm thick). They are placed so they are edge to edge with the element they are next to, but do not overlap. The dimensions at the bottom are given for the distance between the edges of the various elements.

           Beamline Design

Preliminary beamline design to accomodate the desired angular range for the luminosity monitors is still underway. The desire is that all "first bounce" stuff would interact as far upstream as possible, and whatever was needed for the lumi's would not interact in the beamline after this point. The desired angular range for the luminosity monitors is up to .8 degrees.

The limiting aperature here is the beampipe through QTOR. We plan to predict photon rates caused by showers in the beamline and shielding for Regions I and II and the cerenkov bar location for the following two scenarios:

           a single tungsten plug at the upstream cleanup collimator location (limits angular range of lumis)
           a tungsten plug at both cleanup collimator locations (larger lumi angular range, two "hot" spots)

Greg Smith has told us that the beampipe through QTOR should have an inner diameter of 10.25 inches (close to the 10.50 inches we had been hoping for) and a thickness of 3/8 inches (if it is aluminum).

Figure 2a - Rays drawn through geometry (scale x:z = 1:10) to show clearance of beampipe, 1 plug case.	Figure 2b - Rays drawn through geometry (scale x:z = 1:10) to show clearance of beampipe, 2 plug case.
Figure 3a - Unweighted theta_o distribution for the single plug case right after the 1st plug (black) and at the cerenkov bar location (red).	Figure 3b - Unweighted theta_o distribution for the double plug case right after the 1st plug (black) and at the cerenkov bar location (red).

Plug/Location	Normal theta max (degrees)	Extreme theta max (degrees)
Single Plug, upstream cleanup	.52	.89
First Plug, upstream cleanup	.85	1.45
Second Plug, downstream cleanup	.83	.91

           Drift Chamber Update

1. Continued data-taking on drift time distributions has been interrupted by a problem with our VME DAQ. It appears to be the module on the VME side of the VME-PCI interface. We will attempt to get a replacement module from the vendor in the next few days.
2. Drawings for the frames for the second prototype have been submitted to our shop.
3. We have a digital height gauge and a camera (lens is ordered) that we will use to measure wire locations as we build our chambers.