T0 installation procedure
Description of the support structure for the T0 counters:
On each nosecone arm, a stainless steel (1 mm thick, 7.5 cm wide) band will be wrapped around the nosecone near the back of the space allotted for the inner coil (i.e. at a z between 650 and 810 mm). This band will be held in place by tension by clamping the two ends together. To align the band, a screw will be run through the band into the nosecone at a well-known position on both objects. In the phi region subtended by the T0 counters, there will be attachments on the band to which the platform for the support structures of the T0 counters will be attached. This platform will, if possible, be designed so that it can be fastened to the band after the band is in place on the nosecone. The support structures for each T0 counter consists of a form-fitted clamp which encloses the light guide and is attached to the platform via a structure that allows some variation in the z-position. This variation is required to allow for relative movement of the nosecones.
Design Requirements for the support structure for the T0 counters:
|(1)||-||any piece of it must weight less than 40 lbs. so that it can safely handled by one person (since there can only be two people on the MVD table at one time),|
|(2)||-||the adjustable part for handling shifts in the z-position must be positioned between the support for attaching the end of a T0 counter to the platform and the support which attaches the platform to the steel band (since the mounts must allow for each T0 counter to move independently of the other T0 counters),|
|(3)||-||the band is should be made from one or two straps (the T0 group made it from one),|
|(4)||-||if possible, the band should be at least 3" wide because Tom feels that there is ample space for a thicker band and a thicker band is more sturdy (the T0 group made it 7.5 cm wide), and|
|(5)||-||if needed, an aluminium carrying bracket should be designed for the
counters so that they can be carried safely into the IR (since no one
wants the glue joints to fracture during installation).
The T0 group will discuss these matters with the engineer who is doing this design and let us know if they can meet them. So, there is a bit more discussion needed here to converge upon a final design/plan.
And, finally, the T0 group intends to test the installation of the device using a "mockup" of the nosecone and will figure out the path for bringing the T0 counters from the gate to vertex region prior to closing up for HI running.
Preinstallation Checklist for the T0 counters:
Prior to installation, the following items need to be collected:
|(2)||-||18 + spare HV cables,|
|(3)||-||18 + spare signal cables,|
Starting Assumptions about preparation steps for the installation:
|(A)||-||the East and West carriage have been retracted so that access to the vertex region is possible. In particular, for bringing in the T0 counters, the ideal place for handing up the counters to people working on the MVD platform is between the west arm and the vertex region. So, we will need to be able to reach the space between the west carriage and the vertex region without moving the south muon magnet. This may be possible by walking around the back of the south muon magnet or between the west arm and the wall.|
|(B)||-||the He-bag has been retracted and its strings have been cut away.|
These assumptions have been made in the following plan because this work is included in the plan developed for the NTC+MVD installation.
With this said, the installation procedure for the T0 counters looks something like:
|Step 2||-||install an extension to the east side of the MVD platform. |
An extension platform (8' by 29") would be attached to the east end of
the MVD platform to allow people to work further out on the east side of
|Step 2||-||mark the Z-position of the edge of the band on each nosecone
When in place, the support structure for the T0 counters is attached to
a 1 mm thick, 7.5 cm wide, stainless steel band. This band will be seated
near the back of the inner coil space (i.e. z between 650 and 810 mm). By
marking the position of the edge of this band, it will be possible to
check that the band is oriented in z correctly as the band is
|Step 3||-||Attach a band for supporting the counters to nosecone of each arm
The support structure for the T0 counters is attached to a stainless
steel (2-5 mm thick, 3" wide) band. This band will be seated near the back
of the inner coil space (i.e. z between 650 and 810 mm).
|Step 4||-||Check alignment of the phi (azimuthal) angle of each band |
The bands will then be fixed in place with a screw into the nosecone at
a points which are well-known. To check that the orientation is correct,
aluminium cross bars will be attached to the bands at points along the
edge of the T0 support structure so that the bars run across the vertex
region. If necessary (and we hope not), the bands on each arm will then be
adjusted in phi until the bars are not being torqued.
|Step 5||-||Attach the platform to the band on each arm |
The platform is composed of individual mounts for each end of the T0
counter. These mounts are fastened to the band via screws into attachments
which have been welded to the steel band.
|Step 6||-||Attach T0 counters to the support structure |
Installed one at a time, each counter is completely assemblied, i.e.
with light guides and PMTs on each end and wrapped in light-tight
material. The PCR will be attached to the inner-facing surface of each
counter but the readout ends of the fibers from this device are not be
attached to anything. These fibers, after all T0 counters are installed,
will be bunched into one phototube.
|Step 7||-||collect PCR fibers from all of the T0 counters on each arm and
attach them to the PCR phototubes |
|Step 8||-||installation of the signal and HV cables |
|Step 9||-||test device and fix problems |
And, finally, as in the NTC+MVD plan, we would have reinstall the He-bag, move the carriages back, clean up our mess, etc. These items are documented in the latter plan and thus need not be included in this plan. So, the total time for the T0 installation (without any continguency and no time allocated for testing and fixing problems at the end!!!!) is 25.0 hours. Of course, this number should be taken with a grain of salt at the moment because the design process is still underway.
Contact person for T0 Installation matters: Susumu Sato
(firstname.lastname@example.org), Masaya Ono (email@example.com), Hiroshi Tsuruoka (firstname.lastname@example.org)