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).
COMMENTS: After working with the T0 counters in Japan, the T0 group has concluded that an carrying bracket is not needed because the glue joints are strong enough.

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:

(1) - extension platform,
(2) - 18 + spare HV cables,
(3) - 18 + spare signal cables,
(4) - tools: ,

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.
Estimated Time : 1 hour

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 the experiment.


(1) According to Peter Kroon, this platform has been used in the past and thus should not present a safety issue.

Step 2 - mark the Z-position of the edge of the band on each nosecone
Estimated Time : 2 hours

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 installed.


(1) the MVD cabling makes access to the inner coil region in the lower phi area difficult. Some care will need to be taken to avoid damaging the cabling.

Step 3 - Attach a band for supporting the counters to nosecone of each arm
Estimated Time : 3 hours

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).


(1) the MVD cabling makes access to the inner coil region in the lower phi area difficult. Some care will need to be taken to avoid damaging the cabling.

Step 4 - Check alignment of the phi (azimuthal) angle of each band
Estimated Time : 4 hours

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.


(1) Principally, the alignment of the bands will be accomplished by a screw through each band into a hole in the nosecone whose position is well-known.
(2) The necessary screw hole was put into each nosecone by Tom before the start of the HI running. These holes are located at the bottom (i.e. facing the ground) of the nosecones.
(3) The T0 group is very concerned about the relative alignment of the bands on each arm. If, for example, the band on one arm is rotated relative to the other, then the support structure will torque the T0 counters -- a very undesireable situation. For this reason, the T0 group wants to be sure that they have some time to check for a problem and, as necessary, deal with it.
(4) If the bands are misaligned, the T0 group would have to loosen one of bands to correct the problem. In this case, one of the bands will not align with the screwhole.

Step 5 - Attach the platform to the band on each arm
Estimated Time : 4 hours

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.


(1) Although the space is confined, Tony and Tom estimated that, based upon the dimensions of the platform and those inner coil gap, it is possible to reach the proposed screw positions. But, it will be difficult to see the screw well, so the head should probably be an allen head.

Step 6 - Attach T0 counters to the support structure
Estimated Time : 45 minutes per counter (this estimate is generous) for a total of 6 hours for all 8 counters

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.


(1) Each T0 counter weighs around 10 lbs and thus can be transported by two people easily and held by one person as needed during the installation process.
(2) We looked at how we would carry the counters into the area and think that the best way is to carry them to position the west carriage such that we can walk behind it on our way into the detector area and hand the counter to two people standing on the MVD table from the west side. These two people would then raise the MVD table to beam height and install the detector using a form-fitted clamps which closes around the light guides.

Step 7 - collect PCR fibers from all of the T0 counters on each arm and attach them to the PCR phototubes
Estimated Time : 2 hours which I feel is very conservative (20 minutes for attaching the fiber to the PMT because of a nice design for the joint, the rest for light-sealing the joint using light sheilding tape applied over the joint region)
Step 8 - installation of the signal and HV cables
Estimated Time : 3.0 hours


(1) The T0 counters require 16 HV and 16 signal cables, 8 for the north side, 8 more for the south side. These cables, along with a spare cable, will be run with the NTC cabling.
(2) The PCR counters require 2 HV and 2 signal cables, 1 for the north side, 1 more for the south side. As with the T0 cables, these two cables will be run with the NTC cabling.

Step 9 - test device and fix problems
Estimated Time : unknowable (say 4 hours like in NTC+MVD plan)


(1) Since neither the T0 or PCR detectors have pulsers, the best way to check the detectors is to look at a source.

If a problem is located, replacing of a T0 or PCR detector with one of the spares can be accomplished in approximately two to six hours. depending upon the position of the defective counter. The exact procedure for such work is presently being developed by the T0 group.

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 (ssato@bnl.gov), Masaya Ono (masaya@bnl.gov), Hiroshi Tsuruoka (tsuru@bnl.gov)

updated 08-October-2001