Integration thoughts... (fwd)

[Elton Smith <elton@jlab.org>]

---------- Forwarded message ----------
Date: Thu, 07 Jun 2001 09:57:24 -0500
From: Eric Scott <ebscott@indiana.edu>
To: Task-d <task-d@dustbunny.physics.indiana.edu>, Elton Smith <elton@jlab.org>
Subject: Integration thoughts...

Hi Elton

    I think we are missing the most important element to the integration
meeting. The actual information needed to integrate all of the
subsystems systems.  Things that must be decided before any individual
detector design or construction can start are:

    1)  A global coordinate system for Hall D.  (What is +X, +Y, +Z or
Beam right and Beam Left....)  This will clarify communication and
standardize design notation.

    2)  Installation procedure for equipment inside solenoid (does each
group install or do we have an installation group?)

    3)  Determine envelope dimensions, service routing, alignment,
mechanical attachments, etc... for all detectors inside of the solenoid
as soon as possible.

    4)  We must decide on the inter system clearances (Babar used 20 mm)

    5)  We need to establish a "good neighbor policy" or define a set of
guide lines concerning heat dissipation, RF noise, staying inside of
established design volume, etc...

    6)  Determining "common fixtures"  structures or services that
multiple subsystems can attach to.  (structural support assemblies,
electrical power services, cooling, gas, cryo etc....)

    7) Finalize the shape of the solenoid: hopefully this means we are
opening up the upstream end of the solenoid so that it is the same size
as the bore then most access can occur through the upstream end.  This
means that the target, and everything inside of the barrel calorimeter
would be removed from the upstream end.

  8) Everything must interface to or anchor through the Barrel
calorimeter.  The barrel calorimeter consumes the entire inner surface
of the solenoid meaning that it either must be part of the support
structure for everything inside of it or it must have support brackets
built into its design to allow for loads to be transferred to the magnet
iron.

  9)  Insertion and extraction of target:  I think the Target should
probably be places on a railed cart that allows it to easily be inserted
or extracted from the front of the solenoid.

  10)  Multi use infrastructure:  This Target rail system can probably
also be used for the insertion and extraction of the chamber packages
etc...

  11)  Is the Vertex Chamber part of Target or tracking package?  For
alignment and support reasons, I would lean toward attaching the vertex
chamber to the target mechanism.

  12)  How to survey inside the solenoid, or do we need to?  Survey of
the equipment inside the solenoid is going to be a problem.  We should
determine the precision that the elements location must be known to now
because this will have a direct impact on the design cycle and costs.
One thought is to make all the chambers into one unit that rests on
"rails" inside the Barrel Calorimeter.  Then if access is needed the
entire assembly can be extracted and worked on or aligned as a unit.

    13)  How do the cables get to the electronics?  Are the electronics
near the detectors or in the control room?  Do the cables take the
"short" path from the magnet (up in the air) to the electronics racks or
do they go down to the floor and then back up?  If they use the "short"
path do we need troughs in the floor?  Does it make sense to design a 2
story rack platform next to the Solenoid?  (If the electronics are in
the hall then this would be a "good" use of space because cables can
came into the second floor and go up to the racks above or down to the
racks below.)

    14)  Where to route all the cables.  I think All cables and services
for everything inside of the barrel calorimeter should come out the
upstream end of the solenoid with the exception of the down stream end
of the Barrel calorimeter, Cerenkov Detector, TOF Wall and LGD.  Access
issues with the Cerenkov detector make having to get into that area
difficult, if we were to route some cables out of the DS end.

    15)  Do the detector packages break as units for removal or do you
have to un-cable everything... I think that cables and services should
probably be "broken" around the upstream face of the solenoid to make
maintenance easier.  Detector packages can then be removed from the
bore, disconnected and rigged to a maintenance area away from the
crowded upstream face without moving the very compact cabling that will
have to be around the chambers.

    16)  CAD package...  If we are all using SDRC IDEAS (available for
free) then do we need to adopt some standard CAD etiquette, a
repository, overall assembly and interference checking and a person
(designer)/ institution (JLAB) responsible for maintaining etc. this
thing?

    I found a resource that may prove useful Babar's TDR:
http://www.slac.stanford.edu/BFROOT/www/doc/TDR/
Their TDR chapter 14 is about:  Facilities, Assembly, Access and
Integration and they touch on many of the issues we have to deal with
now.

    I hope that between your list and these comments the creative juices
will start flowing for a productive meeting.

Cheers,

    Eric

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Indiana University              FAX:   (812) 855-0440
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      Email: ebscott@indiana.edu


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