**MINOS Far Detector**

# **Clear Fiber Installation and Routing**

## J. Musser

Overview [3](#overview)

MINOS Clear Fiber Cable Plant [3](#minos-clear-fiber-cable-plant)

Clear Fiber Cable Description and Labeling
[5](#clear-fiber-cable-description-and-labeling)

General Description [5](#general-description)

Cable Labeling Schema [5](#cable-labeling-schema)

Estimated Cable Lengths [5](#estimated-cable-lengths)

Routing/Fixtures [12](#routingfixtures)

Routing Diagram [12](#routing-diagram)

On-Detector Routing Fixtures [14](#on-detector-routing-fixtures)

Installation [15](#installation)

Initial Mounting of the Cables to a Module Plane
[15](#initial-mounting-of-the-cables-to-a-module-plane)

Completion of the Installation -- Mounting Cables to the MUX Box
[15](#completion-of-the-installation-mounting-cables-to-the-mux-box)

Post Installation Tests of Light Integrity and Transmittance
[15](#post-installation-tests-of-light-integrity-and-transmittance)

Estimated Time/Manpower Requirements for Clear Cable Installation
[16](#estimated-timemanpower-requirements-for-clear-cable-installation)

Clear Fiber Cable Development Status
[16](#clear-fiber-cable-development-status)

Milestones [16](#milestones)

Areas of Concern [16](#areas-of-concern)

# Overview

In this memo, we describe the clear fiber cable routing and installation
for the MINOS far detector. We begin with a general description of the
routing problem, the properties of the cable as they relate to routing,
and a proposed scheme for cable labeling. The implementation of the
cable routes are described next, including a description of the cable
mounting fixtures needed both on and off the detector. The installation
process is described next, including the post-installation test
procedure. Finally, an estimate of the time and manpower requirements of
the clear fiber installation is made, based on our experience with the 4
PPT.

## MINOS Clear Fiber Cable Plant

The MINOS scintillator strips are grouped in modules of either 20 or 28.
A scintillator plane consists of 8 such modules (four of which are 28
wide and four 20 wide), oriented at an angle of +/- 45 degrees with
respect to the horizontal. Associated with each module are two clear
fiber cables, running from either end of the module to MUX boxes located
in racks running along the length of the detector. The on-detector wire
routing paths for the clear fiber are shown in Figure 1. The MUX boxes
are contained in the top-most and bottom-most set of racks shown in this
figure. A schematic representation of the position of the MUX box racks
along the detector is shown in Figure 2. Each MUX box terminates the
cables from one quadrant of two planes of detectors. There are 8 MUX
boxes in each rack, for a total of 16 plane quadrants per rack. The
nominal longitudinal distance between racks is 2 m. The cable runs along
the detector axis needed to reach the rack is, through common usage,
referred to as the 'z run' of the cable route.

![](media/image1.jpeg){width="5.9944444444444445in"
height="4.631944444444445in"}

Figure 1: Face View of Far Detector Cable Routes

![](media/image2.jpeg){width="5.991666666666666in" height="6.325in"}

Figure 2: Longitudinal MUX Box Rack Location

# Clear Fiber Cable Description and Labeling

### General Description

The clear fiber cables constituting the optical connections between the
MINOS scintillator modules and MUX boxes are made up of either 20 or 28
individual 1.2 mm fibers, jacketed with an opaque, fire resistant
coating to a total diameter of 2 mm. The jacketed fibers in the cables
associated with 20-wide modules are bonded into two planar ribbons of 10
fibers each, while the cables associated with 28-wide modules are
grouped in two sets of 10-wide and one set of 8-wide ribbons. The fibers
are separated into individual strands for a distance of 35 cm from each
connector to allow insertion into the connector. For the remainder of
the cable length, the two (or three) ribbons are stacked one on top of
the other and tied together at roughly 0.5 meter intervals to form a
bundle of 2.2 cm in width, and approximately 5 mm in thickness. **A
minimum bend radius of 12 cm must be observed at all times during the
handling, installation, and final routing of the cables.** The cables
have two labels at each end -- one indicating the cable length in
meters, and the other a containing a unique cable identifier. The cables
will have been fully tested for light integrity and attenuation length
prior to shipment to the far detector site. The cables will be re-tested
as part of the module testing procedure, conducted before the plane is
raised to the vertical position.

### Cable Labeling Schema

Since no two cables going to a given MUX box rack have the same length,
and, in addition, the two ends of a given cable are not interchangable,
it is necessary to provide each cable end with a unique designator.
These designators will be in the form

*SM \#* .*plane \#* .*mod. #.end \#* Mod/MUX

e.g. 1.10.5.0MUX and 1.10.5.0MOD are the two ends of the cable
associated with the lower end of the 5^th^ module on plane 10 in
supermodule 1. The planes are numbered from 1 to 242, starting from the
front (FNAL side) of the detector. The modules are numbered from 1 to 8,
with the module with the lowest vertical position being module 1. The
side of the module nearest the floor is designated side 0, with the
opposite side designated side 1.

## Estimated Cable Lengths 

The present estimate of the cable lengths are based on the cable run
lengths used on the 4 PPT, with adjustments for the 'Z' run lengths of
each cable for the full detector configuration. Table 1 lists the
nominal cable run lengths for each cable, not including the Z routing
length appropriate for a given plane. This table also indicates the
fiber 'pin out' on both the MUX and detector module side of each cable.
The pin numbers listed are with respect to pin 1 as labeled on the
connectors. Table 2 lists the additional Z routing lengths associated
with each plane. The cable lengths obtained from these tables should be
regarded as provisional - the final cable routing lengths will be based
on incorporating the full cable routes into the 3D model of the far
detector. This is TDB as of Jan 99.

  ----------- ----------- ----------- ---------- ----------- --------- --------- ---------- ----------
  **Cable**   **Route**   **Cable**   **\#       **Cable**   **Fiber   **Fiber   **Fiber    **Fiber
                                      fibers**               1**       n**       1**        n**

              **Length    **Length               **Type**    **MUX     **MUX     **Module   **Module
              (m)**       (m)**                              side**    side**    side**     Side**

                                                             **Pin**   **Pin**   **Pin**    **Pin**

                                                                                            

                                                                                            

  *s.p.*1.1   3.43        3.73        28         InvL        1         28        28         1

  *s.p.*2.1   1.63        1.93        28         InvL        1         28        28         1

  *s.p*.3.1   1.88        2.18        20         InvL        1         20        20         1

  *s.p*.4.1   1.80        2.10        20         InvH        1         20        30         11

  *s.p*.5.1   2.41        2.71        20         InvH        1         20        30         11

  *s.p*.6.1   3.18        3.48        20         InvH        1         20        30         11

  *s.p.*7.1   3.96        4.26        28         InvH        1         28        30         3

  *s.p.*8.1   5.77        6.07        28         InvH        1         28        30         3

  *s.p*.1.0   6.45        6.75        28         NorH        1         28        3          30

  *s.p*.2.0   4.65        4.95        28         NorH        1         28        3          30

  *s.p*.3.0   3.86        4.16        20         NorH        1         20        11         30

  *s.p*.4.0   3.07        3.37        20         NorH        1         20        11         30

  *s.p*.5.0   2.41        2.71        20         NorH        1         20        11         30

  *s.p.*6.0   2.36        2.66        20         NorL        1         20        1          20

  *s.p*.7.0   2.57        2.87        28         NorL        1         28        1          28

  *s.p*.8.0   4.37        4.67        28         NorL        1         28        1          28
  ----------- ----------- ----------- ---------- ----------- --------- --------- ---------- ----------

Table 1

Clear Fiber Cable On-Detector Run Lengths and Pinnout

  ----------- ----------- ---------------- ---------------- ---------------
  **Plane**   **View**    **Rack**         **Rack Z (cm)**  **Z-Run (cm)**

                                                            

  1           U           1u               106.7            100.8

  2           V           1v               106.7            94.9

  3           u           1u               106.7            88.9

  4           v           1v               106.7            83.0

  5           u           1u               106.7            77.0

  6           v           1v               106.7            71.1

  7           u           1u               106.7            65.2

  8           v           1v               106.7            59.2

  9           u           1u               106.7            53.3

  10          v           1v               106.7            47.3

  11          u           1u               106.7            41.4

  12          v           1v               106.7            35.5

  13          u           1u               106.7            29.5

  14          v           1v               106.7            23.6

  15          u           1u               106.7            17.6

  16          v           1v               106.7            11.7

  17          u           1u               106.7            5.8

  18          v           1v               106.7            -0.2

  19          u           1u               106.7            -6.1

  20          v           1v               106.7            -12.1

  21          u           1u               106.7            -18.0

  22          v           1v               106.7            -23.9

  23          u           1u               106.7            -29.9

  24          v           1v               106.7            -35.8

  25          u           1u               106.7            -41.8

  26          v           1v               106.7            -47.7

  27          u           1u               106.7            -53.6

  28          v           1v               106.7            -59.6

  29          u           1u               106.7            -65.5

  30          v           1v               106.7            -71.5

  31          u           1u               106.7            -77.4

  32          v           1v               106.7            -83.3

  33          u           2u               289.6            93.6

  34          v           2v               289.6            87.7

  35          u           2u               289.6            81.7

  36          v           2v               289.6            75.8

  37          u           2u               289.6            69.9

  38          v           2v               289.6            63.9

  39          u           2u               289.6            58.0

  40          v           2v               289.6            52.0

  41          u           2u               289.6            46.1

  42          v           2v               289.6            40.2

  43          u           2u               289.6            34.2

  44          v           2v               289.6            28.3

  45          u           2u               289.6            22.3

  46          v           2v               289.6            16.4

  47          u           2u               289.6            10.5

  48          v           2v               289.6            4.5

  49          u           2u               289.6            -1.4

  50          v           2v               289.6            -7.4

  51          u           2u               289.6            -13.3

  52          v           2v               289.6            -19.2

  53          u           2u               289.6            -25.2

  54          v           2v               289.6            -31.1

  55          u           2u               289.6            -37.1

  56          v           2v               289.6            -43.0

  57          u           2u               289.6            -48.9

  58          v           2v               289.6            -54.9

  59          u           2u               289.6            -60.8

  60          v           2v               289.6            -66.8

  61          u           2u               289.6            -72.7

  62          v           2v               289.6            -78.6

  63          u           2u               289.6            -84.6

  64          v           2v               289.6            -90.5

  65          u           3u               472.4            86.3

  66          v           3v               472.4            80.4

  67          u           3u               472.4            74.5

  68          v           3v               472.4            68.5

  69          u           3u               472.4            62.6

  70          v           3v               472.4            56.6

  71          u           3u               472.4            50.7

  72          v           3v               472.4            44.8

  73          u           3u               472.4            38.8

  74          v           3v               472.4            32.9

  75          u           3u               472.4            26.9

  76          v           3v               472.4            21.0

  77          u           3u               472.4            15.1

  78          v           3v               472.4            9.1

  79          u           3u               472.4            3.2

  80          v           3v               472.4            -2.8

  81          u           3u               472.4            -8.7

  82          v           3v               472.4            -14.6

  83          u           3u               472.4            -20.6

  84          v           3v               472.4            -26.5

  85          u           3u               472.4            -32.5

  86          v           3v               472.4            -38.4

  87          u           3u               472.4            -44.3

  88          v           3v               472.4            -50.3

  89          u           3u               472.4            -56.2

  90          v           3v               472.4            -62.2

  91          u           3u               472.4            -68.1

  92          v           3v               472.4            -74.0

  93          u           3u               472.4            -80.0

  94          v           3v               472.4            -85.9

  95          u           3u               472.4            -91.9

  96          v           3v               472.4            -97.8

  97          u           4u               655.3            79.2

  98          v           4v               655.3            73.2

  99          u           4u               655.3            67.3

  100         v           4v               655.3            61.3

  101         u           4u               655.3            55.4

  102         v           4v               655.3            49.5

  103         u           4u               655.3            43.5

  104         v           4v               655.3            37.6

  105         u           4u               655.3            31.6

  106         v           4v               655.3            25.7

  107         u           4u               655.3            19.8

  108         v           4v               655.3            13.8

  109         u           4u               655.3            7.9

  110         v           4v               655.3            1.9

  111         u           4u               655.3            -4.0

  112         v           4v               655.3            -9.9

  113         u           4u               655.3            -15.9

  114         v           4v               655.3            -21.8

  115         u           4u               655.3            -27.8

  116         v           4v               655.3            -33.7

  117         u           4u               655.3            -39.6

  118         v           4v               655.3            -45.6

  119         u           4u               655.3            -51.5

  120         v           4v               655.3            -57.5

  121         u           4u               655.3            -63.4

  122         v           4v               655.3            -69.3

  123         u           4u               655.3            -75.3

  124         v           4v               655.3            -81.2

  125         u           4u               655.3            -87.2

  126         v           4v               655.3            -93.1

  127         u           4u               655.3            -99.0

  128         v           4v               655.3            -105.0

  129         u           5u               838.2            72.0

  130         v           5v               838.2            66.0

  131         u           5u               838.2            60.1

  132         v           5v               838.2            54.2

  133         u           5u               838.2            48.2

  134         v           5v               838.2            42.3

  135         u           5u               838.2            36.3

  136         v           5v               838.2            30.4

  137         u           5u               838.2            24.5

  138         v           5v               838.2            18.5

  139         u           5u               838.2            12.6

  140         v           5v               838.2            6.6

  141         u           5u               838.2            0.7

  142         v           5v               838.2            -5.2

  143         u           5u               838.2            -11.2

  144         v           5v               838.2            -17.1

  145         u           5u               838.2            -23.1

  146         v           5v               838.2            -29.0

  147         u           5u               838.2            -34.9

  148         v           5v               838.2            -40.9

  149         u           5u               838.2            -46.8

  150         v           5v               838.2            -52.8

  151         u           5u               838.2            -58.7

  152         v           5v               838.2            -64.6

  153         u           5u               838.2            -70.6

  154         v           5v               838.2            -76.5

  155         u           5u               838.2            -82.5

  156         v           5v               838.2            -88.4

  157         u           5u               838.2            -94.3

  158         v           5v               838.2            -100.3

  159         u           5u               838.2            -106.2

  160         v           5v               838.2            -112.2

  161         u           6u               1021.1           64.8

  162         v           6v               1021.1           58.9

  163         u           6u               1021.1           52.9

  164         v           6v               1021.1           47.0

  165         u           6u               1021.1           41.0

  166         v           6v               1021.1           35.1

  167         u           6u               1021.1           29.2

  168         v           6v               1021.1           23.2

  169         u           6u               1021.1           17.3

  170         v           6v               1021.1           11.3

  171         u           6u               1021.1           5.4

  172         v           6v               1021.1           -0.5

  173         u           6u               1021.1           -6.5

  174         v           6v               1021.1           -12.4

  175         u           6u               1021.1           -18.4

  176         v           6v               1021.1           -24.3

  177         u           6u               1021.1           -30.2

  178         v           6v               1021.1           -36.2

  179         u           6u               1021.1           -42.1

  180         v           6v               1021.1           -48.1

  181         u           6u               1021.1           -54.0

  182         v           6v               1021.1           -59.9

  183         u           6u               1021.1           -65.9

  184         v           6v               1021.1           -71.8

  185         u           6u               1021.1           -77.8

  186         v           6v               1021.1           -83.7

  187         u           6u               1021.1           -89.6

  188         v           6v               1021.1           -95.6

  189         u           6u               1021.1           -101.5

  190         v           6v               1021.1           -107.5

  191         u           6u               1021.1           -113.4

  192         v           6v               1021.1           -119.3

  193         u           7u               1204             57.6

  194         v           7v               1204             51.7

  195         u           7u               1204             45.7

  196         v           7v               1204             39.8

  197         u           7u               1204             33.9

  198         v           7v               1204             27.9

  199         u           7u               1204             22.0

  200         v           7v               1204             16.0

  201         u           7u               1204             10.1

  202         v           7v               1204             4.2

  203         u           7u               1204             -1.8

  204         v           7v               1204             -7.7

  205         u           7u               1204             -13.7

  206         v           7v               1204             -19.6

  207         u           7u               1204             -25.5

  208         v           7v               1204             -31.5

  209         u           7u               1204             -37.4

  210         v           7v               1204             -43.4

  211         u           7u               1204             -49.3

  212         v           7v               1204             -55.2

  213         u           7u               1204             -61.2

  214         v           7v               1204             -67.1

  215         u           7u               1204             -73.1

  216         v           7v               1204             -79.0

  217         u           7u               1204             -84.9

  218         v           7v               1204             -90.9

  219         u           7u               1204             -96.8

  220         v           7v               1204             -102.8

  221         u           7u               1204             -108.7

  222         v           7v               1204             -114.6

  223         u           7u               1204             -120.6

  224         v           7v               1204             -126.5

  225         u           8u               1386.8           50.3

  226         v           8v               1386.8           44.4

  227         u           8u               1386.8           38.5

  228         v           8v               1386.8           32.5

  229         u           8u               1386.8           26.6

  230         v           8v               1386.8           20.6

  231         u           8u               1386.8           14.7

  232         v           8v               1386.8           8.8

  233         u           8u               1386.8           2.8

  234         v           8v               1386.8           -3.1

  235         u           8u               1386.8           -9.1

  236         v           8v               1386.8           -15.0

  237         u           8u               1386.8           -20.9

  238         v           8v               1386.8           -26.9

  239         u           8u               1386.8           -32.8

  240         v           8v               1386.8           -38.8

  241         u           8u               1386.8           -44.7

  242         v           8v               1386.8           -50.6
  ----------- ----------- ---------------- ---------------- ---------------

Table 2

Z Run Distances

# 

# Routing/Fixtures

### Routing Diagram

The cables servicing a single detector plane are tied to that plane
using a set of aluminum rods bolted to the edge of the steel. The
locations of these tie points are shown in Figure 3. A detail showing
the tie point rod lengths as implemented on the 4 PPT is shown in Figure
4.

![](media/image3.jpeg){width="5.89375in" height="6.524305555555555in"}

Figure 3

![](media/image4.jpeg){width="5.793055555555555in"
height="5.793055555555555in"}

### 

Figure 4: Cable Tie Point Detail

### On-Detector Routing Fixtures 

Examples of tie point fixtures on the 4 PPT are shown in Figures 5-7.

![](media/image5.jpeg){width="3.8in" height="2.73125in"}

Figure 5 -- Tie Point at Location 'A' in Figure 1

![](media/image6.jpeg){width="3.941666666666667in"
height="2.9993055555555554in"}

Figure 6-- Tie Point at Location B in Figure 1

![](media/image7.jpeg){width="3.8513888888888888in"
height="3.1729166666666666in"}

Figure 7 -- Tie Point at Location 'E'

## 

# Installation

### Initial Mounting of the Cables to a Module Plane

The initial installation of the clear fiber cables takes place while the
plane is in the horizontal position, after the scintillator modules have
been mounted on the steel plane. Prior to the placement of the
scintillator modules on the steel plane, the cable tie point fixtures
will have been bolted to the steel at the locations shown in Figure 3.
The cable mounting proceeds through the following steps

> 1: The crate containing the cables for the plane under assembly is
> opened.
>
> 2: The face of the module-side connector is coated with the optical
> couplant.
>
> 3: The light seal gasket is slid onto the module connector.
>
> 4: The cable connector is bolted to the module connector
>
> 5: The cable is unrolled, and tied to the appropriate tie points with
> loose cable ties.
>
> 6: Light seal and transmittance tests are conducted on the
> module/cable combination.
>
> 7: The remaining cable is safed at locations E or N, in preparation
> for lifting.

### Completion of the Installation -- Mounting Cables to the MUX Box

After the plane has been lifted into place, the cable routes can be
completed to the MUX box. This is done by running the cables in the 'Z'
direction in cable trays mounted at the height of the lowest MUX box,
and located between the MUX box racks and the detector. The cable ends
are then brought to the MUX box connectors, and coupled using the same
procedure outlined above for the module connections.

### Post Installation Tests of Light Integrity and Transmittance

After final connections have been made to a MUX box, an end to end
system test of the module/cable/MUX box/PMT chain will be conducted
using a radioactive source to excite the scintillator.

### Estimated Time/Manpower Requirements for Clear Cable Installation

The initial installation manpower estimates contained in the MINOS TDR
have been validated by time-motion studies conducted during assembly of
the 4 PPT. The time required to perform the initial cable installation
(the work conducted with the plane in the horizontal position) is 1 hour
per plane, with four assembly technicians assigned to this task. In
addition, 2 hours are required for checking performance and light
integrity. This work is done by two assembly technicians. Final
installation and inspection is accomplished by three technicians in one
hour.

## Clear Fiber Cable Development Status

Development of the cable connectors is essentially complete. In terms of
the fiber itself, to date fiber cables have been constructed only from
simplex (single stranded) fibers -- cables of this type were used to
instrument the 4 PPT. Fabrication of the first large lot (3 km) of
ribbon cable is presently underway, with delivery expected in mid to
late March. At that time, pre-production cables can be fabricated, and
any routing issues specific to the ribbon cable can be addressed through
tests on the 4 PPT. For example, the design of the cable tie points will
need to be modified to accommodate a ribbon cable. The details of the
cable routing along the detector axis have also not been finalized, and
therefore, the cable lengths called out in this memo will be refined
prior to fabrication. The final cable lengths will be determined from a
combination of a more complete 3D model of the cable plant, and
measurements on the 4 PPT.

## Milestones

Final Production Specifications -- RFP released March 1,2000

Receipt of Fiber Ribbon March 15,2000

Fabrication of prototype ribbon cable April 1,2000

Final Fire Safety Review April 15,2000

Fiber/Cable Order Placed June 1,2000

10% SM1 Cable Shipped Dec 30,2000

100% SM1 Cable Shipped Sept 2001

100% SM2 Cable Shipped Oct 2002

## Areas of Concern

The nominal performance of the fiber cable, including the connector
transmittance, attenuation length, light seal, and other mechanical
properties, such as minimum bend radius, has been determined to meet the
MINOS requirements in this area. The primary areas of concern at this
point involve optimizing the yield of good cable in the production
process. Specifically, the fiber produced by Kuraray has isolated
regions occurring at a frequency of roughly 5/km in which the fiber
diameter dramatically exceeds the nominal dimensional tolerances of the
fiber. This has a substantial impact on the jacket fabrication process,
which must be able to tolerate these excursions. We are presently
working with both the fiber and jacket manufacturers to find a
specification which optimizes the product of the fiber and jacket
yields.

During installation, the primary area of concern is that the necessary
level of attention to obeying the bend radius restrictions, and the
general need to treat these cables with respect, be maintained
throughout the installation period. This will require attention and
sensitivity to this issue on the part of the on-site installation
supervisors.

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