-----Original Message----- From: Peter Winter [mailto:peter.winter@psi.ch] Sent: Thursday, April 27, 2006 4:24 AM To: John Blackburn Cc: David Hertzog; Eric Thorsland; Ron McNabb Subject: Distances Dear all, yesterday Sara and I completed to measure some remaining distances in the area which are still needed for the determination of the length of the vacuum pipe. Let's first start with the drawing I send you in the email on 03/28/2006 as a reminder of the envisioned beam pipe design: I will not repeat the explanations but let me just say that I changed the legend a bit. The numbers on the beam pipes in the drawing refer to the so called standards NW320 and NW250. In the meantime, I learned that these pipes do not have a diameter of 320mm and 250mm, respectively. So whenever I wrote 320mm or 250mm that should be NW320 and NW250 instead. But that doesn't change anything for the design since we end with a NW320 beam pipe and John and Eric will have a connector to this standard size (therefore we shipped a NW320 flange). Okay now the remaining question was to determine the distance from the last quad to the target, or better to that from the end of the last part of the beam pipe that will not be exchanged. That is just the part which transverses the last quad, so the most left NW320 in my upper picture.To understand our measurement, let me post a schematic drawing of the area: To clarify this picture some general remarks first: - All measurements are given in mm - Black distances are our measurements with a folding rule - Green measurements are reference points from the survey group. Note that the direction of the beam corresponds to their x-axis. Their origin is nearby the separator upstream but that's fine since we only need differences (The delta x are calculated by me using their values). - This picture shows the simplified momentary beam pipe arrangement as used for the MuCap experiment We have four references from the survey: the two markers EH1101 and EH1102, the back wall and the target position. In preparation to determine the distance of interest we measured from the beam pipe: 1) the direct distance to the wall (693mm + 4274mm). Due to spatial limits we had to split this one into two steps. 2) the distance to reference point EH1102 (693mm + 269mm + 519mm). Here we used some edge of a metal ground plate being quite perpendicular to the side wall. Using the apropriate delta x values, it's possible to determine the distance from the beam pipe in the last quad to the target. The results are shown in red and regarding the not too precise measurements with the flexible foding rule they agree quite well. So the new design needs to have a length of ~1492mm to the target. But from the first drawing we know that parts of that are used for the installation of the gate valve in between, namely: - 2 NW320-250 reducers (2 x 90mm) - 80mm for the gate valve - 160mm for the pump system - 35mm for the sealing rings (5 x 7mm) That's in total 455mm. Therefore, the Illinois part should be constructed such, that from the left corner of the special reducer (NW320 to 8") to the target we have a distance of 1492-455= 1037mm. I recommend that you should double check my calculations for obtaining this final result. If necessary I can also try to find out the space behind the MuLan ball in order to see if we can take out the 8inch beam pipe at the back side. Hope you could follow my description, greetings Peter PS: I'll post that later to the elog so that the others might also have a look at it.
Attachment:
MuonCorridor Sketch.ppt
Description: MS-Powerpoint presentation
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