To: E614 collaboration
From: Robert Henderson
Date: 28 Mar 2000
Re: Etracting cradle/detector assembly from M13 area

Hello Folks,

  Yesterday I posted a scheme about removal of the cradle/detector
assembly
from M13 area. Last night I realised that having the bundle move in a
9.4 degree arc is not a good way to do it. Obviously those cable on the
inside and being compressed and those on the outside stretched. The
correct
way is for the cable bundle to form a slight S-shape. This post will
replace
that of yesterday as soon as Nate Rodning can delete the first, sorry
about
any confusion if causes.

  Even when the cradle/detector assembly is removed from the magnet it
is
prevented from being rolled or lifted out of the area by it's cable
trays.
This is a problem, since we would like to have the option of taking the
assembly to a clean room. I believe I have such a solution which is
demonstrated in the two drawing also posted. These two .EPS drawings
are:

  M13N.EPS
  --------

  Shows a top view of the TRIUMF M13 area and our manget in the
approximately
correct position. It shows the detector/cradle assembly in the magnet
and in
a withdrawn position (moved 2.4 meters downstream)

  The magenta color shows the two long angle beams that form the new
cradle
design. In this drawing they are 1.975 meters long. The detector stack
is
shown occupying in the central 1.10 meters of the cradle, it is larger,
with
radius about 515 mm.

  In the `out' position the cable bundle (shown in red) and the `lip
extension' (shown in black) are moved away from the cradle by 230 mm.

  LAM-50-D.EPS
  ------------

  This drawing shows and end view of the magnet (from DS) and the
detector
at the central. The solenoid is NOT shown, except for it's inner radius
at
525 mm.

  The two cable bundles are shown coming in through slots in the magnet
top.
They come down 1.6 meters, then become horizontal cable trays that run
along
the sides of the cradle.


Concept
=======

  The concept I have is as follows. The cables will be  in horizontal
cable
trays that run along the sides of the cradle and also in cable trays
from the
top of the magnet to the racks. However, in the region between, when the

cable (and hoses) are vertical, they are NOT in trays. Infact, they are
boud together only loosely, allowing the cable bundle to easily form a
gentle
S-shape. Unlike a single bend, the S-shape puts no tension/compression
on the
cables, providing they are able to slid relative to each other.

  As shown in LAM-50-D.EPS, the slots in the magnet top are NOT centered

over the horizontal tray location (when in use). Rather, they are
displaced
towards the sides. In this figure the displacement is 23 cm.  The cable
bundle on the right is shown in the `in' position. The one on the left
in the
`out' position, the horizontal cable tray (seen in section view) is
lower
because by a mere 30 mm. Obviously when in the `out' position the
horizontal
cable tray needs some support mechanism.

  Note that the `lip extensions' are moving with the cable trays, when
move
to `in' they provide a convenient surface to attach to the cradle L-beam
and
provide a gas seal. Of course, when installed, these trays have to be
screwed into postion and RTV used to seal the helium volume.

  The principl of this scheme is clear. When we wish to remove the
cradle/detector assmebly from the M13 area, we:

1) Slid cradle/detector assembly out of magnet onto `cart'.
2) Remove the helium covers
3) Disconnect the cable from all modules
4) Disconnect the gas hoses (many inputs, few outputs).
5) Disconnect the cable trays from the cradle and swing them clear.
6) Crane cradle/detector assembly aout of area.

  The gas inputs would be relatively easy to disconnect by removing the
cradle bottom plate. If the disconnected polyflo hoses pass between
detector
modules and share the cable tray with the signal cables, they will need
to be
slid through to free them before step 5). If these hoses form their own
hose
bundles in the bottom of the cradle, these bodles must be disconnected
from
the cradle and left behind.

  Either of these options looks like it will work. We may however choose
to
have a panel at the DS end of the cradle to disconnect the lines from
the
cable trays. This panel would stay attached to the cradle and be removed
with
it. Note that the gas lines going from this panel to the gas system
would
also need to be flexible (i.e probably polflo) because of the later 9.4
degree bend.

  With the cable bundles swung clear (and supported on some frame),
there is
a gap created to lift the assembly out.

Regards Robert Henderson

Filename: m13n.eps

Filename: lam-50-d.eps

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