Sept 10, 2003, by Dave Mack

These are the photos provided by Dave Meekins. The target is in the EEL. For the time being, if you have your TLD you can enter the fenced area and take a look.

Figure to right: Upstream view of cryotarget stack. The solid targets are on top with obvious black beam scars on the Aluminum. The two cylindrical cryogenic cells are near the bottom with barely visible beam scars.
Full-size version

Close-up upstream view of cryogenic cells. Radiation damage has eroded some of the super-insulation.

Close-up upstream view of the loop 2 (LH2) cryogenic cell. The beam scar is the light patch. Walking over to the EEL to eyeball, the beam scar is at least 3-4 mm beam left of the center of the target. We will therefore require a significant correction for the target thickness. The target survey below could account for 1.25mm of this offset. (Thanks, Greg.) The rest may be due to a discrepancy between the surveyors DIMAD (0,0,0) and the spectrometer centers of rotation, or perhaps we just set the beam spot wrong.

Close-up upstream view of the loop 3 (LD2) cryogenic cell. The beam scar is not as obvious as in loop 2 but it is similarly misaligned.

Extreme close-up view of the solid targets. At the top is the thick dummy that we didn't use in Fpi. Below that is the standard dummy target used for our target window subtractions.

Another extreme close-up view of the solid targets. Although out of focus, one can see two distinct scars on the standard dummy target (with the darker one possibly created during production running, the lighter one created during shorter tuning periods). The beam scars are roughly +-4mm squares. Since our raster size was nominally +-2mm square, we held the beam spot centroid on target over the entire year to +-1mm. (Hopefully we did even better during Fpi.) I walked over to the EEL and looked myself: the Aluminum dummy target did not melt.

Initial target survey Note that this survey is presumably with the target warm and up to air. Presumably that affects the vertical position more than anything else. We need more information.

Final target survey Note that this survey is presumably with the target warm and up to air. Presumably that affects the vertical position more than anything else. We need more information.