**SCT Power Supply System**

**SCT Patch Panel Three (PP3)**

**\_\_\_\_\_\_\_\_\_\_\_ DRAFT 6 \_\_\_\_\_\_\_\_\_\_\_**

Abstract

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+---+----------+---------+---+-------------+-----+-----+--------------+
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+---+----------+---------+---+-------------+-----+-----+--------------+
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+---+----------+---------+---+-------------+-----+-----+--------------+

#  

  ---------- --------------- --------- ----------------------------------------
  History of                           
  Changes                              

  Rev. No.   Date            Pages     Description of changes

  1          09-May-2003               GFM. First draft

  2          16-May-2003               GFM. Incorporate 'final rack
                                       allocations' from Sergei Maluykov, EDMS
                                       reference ATC-TB-EP-0007 version 1
                                       released 16-May-2003.

  3          03-June-2003              GFM.

  4          13-June-2003              GFM. Comment from Steve Gregory on
                                       circuit layout.

  5          18-June-2003              GFM. Incorporate comments from PP3
                                       Working Meeting held at Uppsala SCT
                                       Week, 17-June-2003.

  6          01-March-2004             GFM. Incorporate change to rack layout,
                                       recent field results. For the review to
                                       be held during SCT Week, 09 March 2004.
  ---------- --------------- --------- ----------------------------------------

#  

# 1. Introduction:

Patch Panel Three (PP3) is implemented as individual isolated units, one
per module cable, located in racks mounted on the HS structure
surrounding ATLAS in the UX15 cavern.

PP3 provides:

-   Interconnection between the heavy gauge Type IV cable from the power
    supplies located in the two neighbouring caverns US15 and USA15, and
    the lighter gauge Type III cable running into the ATLAS detector.

-   Common-mode inductive filters on all lines, both power and control,
    to attenuate any common-mode noise that may be picked up on the long
    run of Type IV cable.

-   Voltage limiter circuits for the high current 3.5V analogue and 4.0V
    digital IC power circuits. The voltage at the power supplies is much
    higher than that at the modules to account for the voltage drop on
    the long cable. This voltage significantly exceeds the safe voltage
    at the ICs, where it could appear under some accidental scenarios
    where the current drops suddenly.

Implementation constraints include the necessity to shield against the
strong fringing magnetic field in the vicinity of the ATLAS Barrel
Toroids which may exceed the saturation field of the inductive cores,
the necessity to preserve the grounding continuity and isolation
conditions, the very high packing density of cable and PP3 boxes
required in the available rack space in UX15, and the necessity for
reasonable access for rapid maintenance.

#  ![](media/image2.png){width="5.124305555555556in" height="3.8430555555555554in"}

# 2. PP3 specifications

  -------------------------------------------- --------------------------
  Common-mode rejection, Vdd/Dgnd and Vcc/Agnd ???

  Common-mode rejection, all other conductors  ???

  Maximum tolerable ambient magnetic field     600 G
  (outside shield)                             

  Voltage limit, Vdd-Dgnd at module measured   5.20V ± ???V
  on sense lines                               

  Voltage limit, Vcc-Agnd at module measured   4.50V ± ???V
  on sense lines                               

  Maximum weight of one PP3 rack mounted on HS 500 kg ?
  support beams                                

  Time to access and replace any individual    1 hour ?
  PP3 unit in a rack                           
  -------------------------------------------- --------------------------

The voltage limiter is required because the maximum voltage at the power
supply significantly exceeds the maximum allowable voltage at the module
ICs due to the large voltage drop on the cables and power tapes. The
maximum design current for both analogue and digital supplies is 1.3 A.
The one-way resistances in the corresponding power circuits are up to
4.0 Ω, leading to maximum total voltage drop of 5.2 V each way, \[2\].
Under certain circumstances, for example a failure of the clock leading
to a sudden reduction of current, this can lead to an unacceptable
voltage at the ICs more rapidly than the power supply microcontroller
can react.

The common mode filters are required to attenuate any noise picked up on
the long cable runs from the power supplies. All conductors, including
the cable screen drain wire, pass through a common mode choke. The metal
box is electrically connected to the module side of the screen choke.
The metal box and the cable screens are electrically isolated from
contact with any other PP3 and all surrounding structures. The ground
plane in the PCB is split at the screen choke.

The fringing magnetic field of the ATLAS Barrel Toroid may be up to
around 600 G in the vicinity of the rack positions on the HS structure,
typically 3 or more metres from the nearest toroid coil. The positions
of the PP3 racks are defined by TC documents in EDMS \[4\]*.* Simulated
field maps for the ATLAS cavern UX15 are also in EDMS \[5\].

Several further requirements relate to the supporting structure for PP3.
A number of rack positions have been allocated in the UX15 cavern
according to many constraints from cable routing and location
possibilities on the HS structure. They will be standard ATLAS 41U
racks. The racks must be supported on the HS eight-level scaffold
structure which surrounds the ATLAS detector. The HS structure is made
of steel beams, with the racks positioned directly over beams for
maximum support. The PP3 racks, fully loaded with cables, PP3 units and
magnetic shields, must not exceed the weight tolerance. Furthermore,
magnetic forces on ferro-magnetic material may be non-negligible.

Another significant constraint is that individual PP3 units should be
reasonably accessible for maintenance. Should a PP3 fail in service, it
would be desirable to be able to replace it rapidly. This imposes
constraints on the internal layout of PP3 and cabling inside the racks.
There may be up to 300 each of Types III and IV cables in the rack which
are likely to obstruct replacement of any individual PP3. Diagnosis of a
PP3 failure is a separate and non-trivial issue. However, as a device
which is in principle accessible, we should certainly allow for the
eventuality.

#  ![](media/image3.png){width="6.257638888888889in" height="7.821527777777778in"}

# 3. Circuit design & layout

The circuit schematic \[6\] and bill of materials \[7\] for the baseline
design of PP3, version 3.0, are available. This version uses 17W5
combination D-sub connectors, of the same configuration as used at the
power supply backplane.

The baseline PP3 consists of a rectangular printed circuit board, 70 x
85 mm. Board layout is shown in figure 2, and a photograph of a
prototype of this design is shown in figure 3. All components except the
connectors are SMD to minimise area, reduce assembly cost and enhance
reliability. All components are mounted on the top surface. The PCB is
2.4 mm thick for extra stiffness, without being too thick for soldering
the connector leads. Copper plating is double weight, 1 oz/sq.inch, to
minimise resistance. The board is hot-air levelled (HAL), i.e. plated
with solder over the copper to further reduce resistance. It is coated
top and bottom with a solder-mask, and finished with a top overlay
legend.

The 17W5 combination D-sub connectors are at either end, connecting to
both cables with identical pin assignment to the power supply backplane.
The input connector for Type IV is a plug on the PCB, and the output
connector for Type III leading to the modules is a socket connector,
identical to that of the power supply crate backplane. Opposite gender
connectors prevent incorrect connection. Circuit topology is simple with
connectors mounted on the same surface of the board, as the traces run
generally in-line without need for crossing from one side to the other.
The specified right-angle PCB connectors are flush with the surface of
the board for extra stiffness and reduced box height. The connectors for
the prototypes have been procured from Conec Corporation[^1]. An
alternative supplier, FCT Electronic Gmbh[^2], is also under
consideration.

Printed circuit board marterial is halogen-free FR4. The final circuit
will be laid out to conform to IPC-221, in particular for the HV traces.
A 5 mm clearance is allowed in most areas between the HV tracks and any
neighbouring conductors or the edge of the board, with further isolation
provided by the solder-mask coating. The mixed D-sub connector includes
fully specified and well-shrouded high-voltage connector and socket
inserts. It also provides on the cable side high-current crimp
connections designed for the 8-10 gauge wires, a feature particularly
difficult to obtain in other compact connector options.

The board is implemented in four layers as follows:

The common-mode suppression circuits are implementations of the design
by Ned Spencer using his recommended chokes. The chokes are commercial
devices from Pulse Engineering[^3], part numbers P0422 for the two high
current circuits, and P0354 and Fil-Mag 23Z105SM for the low current
circuits. The voltage limiter circuit is an implementation of that
developed by the Ljubljana group \[3\] using closely similar, but not
necessarily identical, components from different suppliers. We expect
that the radiation environment is not sufficiently severe to cause
concern for the degradation of the transistors used.

![](media/image4.jpeg){width="4.7340277777777775in" height="3.55in"}

![](media/image5.jpeg){width="5.131944444444445in"
height="3.157638888888889in"}

# 4. Magnetic shield & mechanical layout

The magnetic and electric shield concept is illustrated in figures 4-6.
The box material is fabricated from sheets of 0.5mm thick grain-oriented
silicon transformer steel by RFI Pty Ltd [^4]. This material has a thin
coating of varnsh. Two C-section pieces are spot-welded together to form
a rectangular cylinder with internal dimensions 70 x 19 mm. The length
will be around 200 mm, to be finalised shortly. Shields will be
manufactured by RFI. This geometry is determined by the shape of the
17W5 mixed D-sub connectors used on the printed circuit boards, for
which no acceptable alternative was found.

The PP3 racks will be located in the residual field of the ATLAS barrel
toroids. Simulated field maps indicate that up to 600 G may be present.
The inductive chokes used to attenuate common-mode pickup saturate at
external fields around 100-200 G \[8,9\]. Allowing for a safety margin,
we will require the final shields to reduce 600 G oriented at any
direction relative to the shield to at most 50 G over the volume
occupied by the chokes. This can be achieved by optimisation of the
length and the number of layers of transformer steel.

The magnetic shields will additionally act as electrostatic shields,
extending over the lengths of the two cable connectors. The shield will
be connected by a short lead to the cable screen conductor, downstream
of the chokes. They will be insulated to prevent ground contacts with
each other and with the rack structure. The insulation will also act as
a safety isolation in case of accidental appearance of the detector high
voltage on the shield. The transformer steel is supplied coated with a
thin varnish. However, to ensure a suficiently tough insulation, the
final assembled shields will be dipped in a conformal coating
material[^5].

The cable backshells at PP3, on both the type IV and type III cables,
have yet to be finalised. However, it is assumed they will be
unmetallised plastic with 90º cable entry[^6]. The cable screen drain
wires are connected through the 17W5 signal pins to the PP3 ground
planes. This connection is expected to be reinforced by an additional
low inductance metal or metallised kapton foil inside the backshell.
Electrostatic screening of the wires in the connector is by the extended
PP3 shield. The backshells to be fitted to the production cables should
be selected to fit inside the dimensions of the apertures of the open
faces of the PP3 shield.

The shield concept is illustrated in figure 4. The printed circuit board
is isolated from the metal shields by a sheet of plastic insulation. The
circuit board will be glued to the insulating sheet, and the insulating
sheet to the centre of the bottom shield, with Araldite. The transformer
steel clam-shells are spot-welded together to ensure minimum air gap for
magnetic shielding efficiency. The shield is sufficiently long to
enclose the circuit board as well as the two cable backshells[^7].

#  ![](media/image6.jpeg){width="3.5125in" height="2.634027777777778in"}![](media/image7.jpeg){width="4.063194444444444in" height="1.6645833333333333in"}![](media/image8.jpeg){width="4.064583333333333in" height="1.6145833333333333in"}

# 5. Magnetic shield performance measurements

# The baseline magnetic shield performance has been tested in several ways. The field strength inside the shields has been measured directly using a Hall probe. Also, the direct effect on the frequency characteristics of the cores inside the shields has been measured as a function of external field strength. It should be noted that in the case of the latter technique, the orientation of the toroidal cores in the flat plane of the PCB and shield leads to an insensitivity in the direction normal to the PCB and shield flat surfaces. Consequently, the orientations of interest are those through the open aperture and through the narrow edge of the shield.

# The first shield design proposed utilised a sandwich structure with a core of aluminium. This is a standard approach to achieve good high frequency shielding which is not necessary in this case. Instead, the gap between magnetic sheets at the overlap of the separately formed 'C' pieces, forced by this construction, lead to insufficient low frequency performance. This was shown in measurements in the large Morpurgo superconducting magnet at CERN during July 2003 \[12\] where significant degradation could already be detected at around 200 G ambient field strength in the two directions of interest.

# Following these results, the shield design was changed to simple boxes of silicon transformer steel, spot welded where the 'C' pieces overlap to ensure good magnetic coupling. Two basic designs have been pursued, single thickness and double thickness. Prototype shields 164 mm long with inside dimensions 22 mm and 75 mm were constructed. Two types of test have been performed in Melbourne, low field and strong field.

# In the low-field tests \[11\], a Helmholtz coil was used to generate a field of around 9 G over a volume sufficiently large compared to the shield dimensions to investigate geometry dependence. This field was insufficient to investigate shield saturation effects. The measurements have limited usefulness due to the residual field inside the shields and the measurement errors. However, they demonstrated an order of magnitude reduction in field strength over the volume inside the shield to be occupied by the chokes. Figure 7 shows the field as a function of position for the orientation shown, the shield narrow side in the field direction. The field reaches its minimal level of around 0.5 G at around 50mm from the centre along the shield axis, and is uniform across the width. A similar result was found for the field oriented towards the aperture, where the increase started around 35mm from the centre. This was the case for both shield thicknesses, i.e., no strong dependence on thickness was observed in the two directions in which the chokes are expected to be sensitive. With field perpendicular to the flat surface, the internal field was around 1.8 G for single layer shield, and around 0.9 G for a double layer shield, indicating in this direction the shielding effectiveness does depend on thickness.

In the high-field tests \[12\], a laboratory electromagnet was used to
generate fields between its pole faces of up to around 800 G for the
later shield designs. In these measurements, the field strength exceeds
the values of interest, but the geometry is highly non-uniform over the
size of the shields due to the pole face diameter of only 90 mm.
Furthermore, the separation of the pole faces is insufficient to fit the
shield longitudinally. Nevertheless, these tests are interesting because
they demonstrate the saturation behaviour of the shielding material. For
the field oriented as shown in the previous figure, towards the narrow
edge, the results in Gauss at the centre of the shield are

  ----------------------- ----------------------- -----------------------
  External                Single                  Double

  200                     0.2                     0.4

  400                     15                      1

  600                     90                      3

  800                     185                     25
  ----------------------- ----------------------- -----------------------

from which we can conclude that the double thickness shield is adequate
to strengths well in excess of the 600 G target value. The single layer
shield does not quite meet the target performance of 50 G in an external
field of 600 G. However, as noted previously , the chokes continue to
function in fields up to 100 G. Furthermore, these tests are of shields
in isolation. In the PP3 racks, multiple shields will be close
neighbours which should tend to reduce the field at least for the inside
units.

Several further tests are planned before a final design is proposed.
Firstly, new prototypes with lengths of 200 or 210 mm will be
manufactured. This is the length determined to enclose the cable
connectors as well as the circuit board. These prototypes will be tested
to field strengths well in excess of 600 G in a large, strong magnet at
CERN during the second quarter of 2004. As the superconducting Morpurgo
magnet is not available this year, the new H8 water-cooled MBPS magnet
will be used as soon as installed. Thiss is expcted to be in March or
April, prior to the SPS startup in May.

  -------------- ----------------------------------------------------- ----------------------------------------------------
                 ![](media/image9.jpeg){width="1.1611111111111112in"   ![](media/image10.wmf){width="4.538888888888889in"
                 height="0.6819444444444445in"}                        height="2.4784722222222224in"}

                                                                       ![](media/image11.wmf){width="4.559722222222222in"
                                                                       height="2.511111111111111in"}

  Figure 7:                                                            
  Helmholtz                                                            
  measurement,                                                         
  field applied                                                        
  in the Z                                                             
  direction,                                                           
  measuring                                                            
  Bz(X) at Z=0                                                         
  and\                                                                 
  Bz(Z) at X=0.                                                        
  -------------- ----------------------------------------------------- ----------------------------------------------------

#  6. Cable routing & rack allocation in UX15

PP3 should be mounted as close as practicable to the modules to minimise
the length of and hence voltage drop on the much more resistive Type III
cable, as well as to minimise the fraction of cable length not filtered
by the common-mode chokes. Additionally, PP3 should be sited to minimise
deviation from the most efficient cable routing to keep the combined
lengths of Type III and Type IV cables as short as possible. Practical
choices for PP3 siting are considerably constrained by the available
rack spaces on the HS structure and also by the practical routing of the
massive cable bundles along the foreseen cable trays. PP3 rack
allocation has been performed by Sergei Malyukov of TC as part of the
cable routing optimisation process for all ATLAS cables, in consultation
with the SCT. There have been a number of revisions as more racks have
become available, reducing the installed cable densities.

Final PP3 rack allocations on the HS structure in UX15 are defined in
ATLAS document ATC-TB-EP-0007 on EDMS \[@4\]*,* reproduced in table 1*.*
The locations on either side of the cavern are shown indicatively in
figure 8. The two sides face the US15 and USA15 caverns respectively.
PP3 racks are yellow. Figure 9 is an indicative view of the cable
routing.

PP3 racks with the numbers of PP3 units and packing density calculations
are shown in table 1. These racks will be standard ATLAS 41Ub
electronics racks[^8], 60 x 90 x 190 cm. However, they should not be
fitted with electricity supply, cooling or ventilation. The cavities in
the rack side walls normally used for ventilation and cooling water
pipes should be vacant as they will be used for cable routing.

At time of writing, a further revision of the racks on the higher levels
of the US15 side is underway due to the recent release of a number of
racks by the muon gas system.

![](media/image12.jpeg){width="3.515277777777778in"
height="2.7784722222222222in"}![](media/image13.jpeg){width="3.55625in"
height="2.847916666666667in"}

Table 1 : Rack allocation & cabling

  ---------- ---------------- -------- -------- ------- ------- ------ ------ ------ ----------- ------- --------- -------
  PP3 Group  Location         Total    Cables / Rack ID Type    W (cm) D (cm) H (cm) Footprint   Sq.cm / Volume    Cu.cm /
                              cables   rack                                          (sq.cm)     cable   (cu.cm)   cable

                                                                                                                   

  PP3_1      Cote US/Level 6  880                                                                                  

                                       126      02-35   60x60   60     60     150    3600        28.57   540000    4286

                                       126      02-36   60x60   60     60     150    3600        28.57   540000    4286

                                                                                                                   

                                       126      02-43   60x60   60     60     150    3600        28.57   540000    4286

                                       126      02-44   60x60   60     60     150    3600        28.57   540000    4286

                                       126      02-45   60x60   60     60     150    3600        28.57   540000    4286

                                                                                                                   

                                       126      02-52   60x60   60     60     150    3600        28.57   540000    4286

                                       126      02-53   60x60   60     60     150    3600        28.57   540000    4286

                                                                                                                   

  PP3_2      Cote US/Level 7  584                                                                                  

                                       292      04-52   41Ub    60     90     190    5400        18.49   1026000   3514

                                       292      04-53   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

  PP3_3      Cote USA/Level 8 584                                                                                  

                                       292      23-51   41Ub    60     90     190    5400        18.49   1026000   3514

                                       292      23-52   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

  PP3_4      Cote USA/Level 4 880                                                                                  

                                       293      25-52   41Ub    60     90     190    5400        18.43   1026000   3502

                                       293      25-53   41Ub    60     90     190    5400        18.43   1026000   3502

             Cote USA/Level 2          292      25-52   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

  PP3_5                       584                                                                                  

             Cote USA/Level 2          292      25-53   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

             Cote USA/Level 1          292      25-51   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

  PP3_6      Cote US/Level 2  584                                                                                  

                                       292      02-51   41Ub    60     90     190    5400        18.49   1026000   3514

                                       292      02-52   41Ub    60     90     190    5400        18.49   1026000   3514

                                                                                                                   

  All                         4096     4096                                                                        

                                                                                                                   

  ***Draft   ***20030926***                                                                                        
  11***                                                                                                            
  ---------- ---------------- -------- -------- ------- ------- ------ ------ ------ ----------- ------- --------- -------

![](media/image14.png){width="6.790972222222222in"
height="4.966666666666667in"}

**7. Internal rack layout proposals**

The rack layout must accommodate 295 PP3 units along with the stiff type
III cables and the even stiffer type IV cables. Ideally, the cables will
be routed such that individual PP3 units could be exchanged in case of
failure. The cables should be strain-relieved and bent through
acceptable radii to prevent undue stress on the internal conductors,
particularly at any tight bends. The PP3 magnetic shields should be
fixed against magnetic forces which arise from the fringing field of the
toroids. The cable connectors on both sides should be firmly screwed to
the PP3 connectors with jack-screws to ensure reliable electrical
connections.

The proposed layout consists of a single column of PP3 units mounted in
a 41Ub rack, five units wide and 60 units high, for a total of 300. This
allows for up to seven or eight installed spares. The cable bundles are
routed in the side cavities of the rack. The 15mm diameter type IV
cables in the ventilation space towards the front of the rack, and the
12mm diameter type III in the plumbing space towards the rear of the
rack. All racks have access and doors at both front and rear. All cables
are routed inside the rack volume, entering and leaving from the floor
or roof. Note that in some cases the cables enter and leave trough the
same surface, top or bottom, which leads to additional congestion. The
cable connectors are all 90º entry. This layout is illustrated
schematically in figure 10. Exact mounting details, support bars etc.,
will be determined through trial layouts using the test cables and
electronics racks already installed in building SR1 at CERN during March
and April 2004. The racks, recuperated from Delphi, are closely similar
to those to be installed in UX15. The test cables are considerably more
flexible than either the type III or IV.\
![](media/image15.jpeg){width="4.746527777777778in"
height="4.560416666666667in"}

# 8. Power dissipation and temperature

# The main power dissipation in PP3 arises from the analogue and digital supply currents flowing in the turns of the inductive chokes which have a small resistance \[13\]. Operating currents are typically around 600 mA for Idd and around 900 to 1000 mA for Icc. Maximum values which should used for thermal calculations are 1.2 A each. Measured total resistances on PP3 including the connectors, the circuit board tracks and the choke turns are between 60 and 70 mΩ for the supply and return circuits. Taking 70 mΩ and 1.2 A for the four conductors leads to a maximum power estimate of P = I^2^R = (1.2^2^) \* 0.07 \* 4 = 0.4 W. The small-signal and detector high voltage lines contribute negligibly in comparison even though their resistances are considerably higher, in the order 300 mΩ per conductor.

It is not planned to cool the PP3 units actively, either with fans or
circulated liquid. The main power dissipation occurs in the wire turns
of the chokes which are not well thermally coupled to the PP3 metal
shield. The PP3 metal shield has electrical insulation which also acts
as thermal insulation. The open apertures of the magnetic shields are
effectively blocked by the cable connectors, limiting air flow.
Conductive heat flow will occur through the PCB tracks to the wires of
the cables. The PP3 units will be mounted so as to permit some air-flow
around groups of shields.

Some measurements of operating temperatures of insulated PP3 units
connected by cables will be performed. An important consideration is the
operating temperature of the voltage limiter components. The limiting
voltage is given by \[3,14\]:

Vlim = Vref(1 + Rf/Re) + Vq

where Vref = 2.50 is set by component X1, a TL431 precision shunt
regulator, and Vq = 0.65 is the forward voltage drop of Q1, a BC857
general purpose PNP transistor. From data sheets, Vref has a thermal
coefficient around 50ppm/°C and Vq around -2mV/°C. At 35°C, ten degrees
above nominal, we could expect Vref to rise by 0.5 mV and Vq to drop by
20 mV. Voltage limiter nominal values are 4.50V for Vcc and 5.20V for
Vdd, i.e., 1.0V higher than nominal operating values.

# 9. Production

Production will be organised by the University of Melbourne in
Australia. It is proposed to procure and populate the PCBs in industry,
but to test them in-house. A test kit will also be provided for use
during installation in UX15. A significant fraction of the cost of the
units will be that of the 17W5 connectors. It may be preferable to
procure these in the same order as the 17W5 connectors for the power
supply backplane and cables to obtain the best overall price and to
ensure compatibility.

# 10. References & Related Documents

In the following table, \[pp3\] represents the URL
<http://epp.ph.unimelb.edu.au/epp/projects/pp3/>.

Documents with reference numbers commencing ATL- can be found on EDMS or
CDD at CERN.

+---+---------------------------+--------------------------------------+
|   | Document reference        | Document                             |
+---+---------------------------+--------------------------------------+
| 1 | ATL-IS-ES-0042            | *SCT Power Supply Distribution*      |
+---+---------------------------+--------------------------------------+
| 2 | Reference ???             | *Voltage drops in the SCT power      |
|   |                           | distribution*                        |
+---+---------------------------+--------------------------------------+
| 3 | \                         | *Voltage limiter circuit*            |
|   | [pp3\]/docs/LimReport.pdf |                                      |
|   |                           | The Ljubljana ATLAS group            |
+---+---------------------------+--------------------------------------+
| 4 | ATC-TB-EP-0007            | *ATLAS rack layout in USA15, UX15    |
|   |                           | and US15 caverns*                    |
+---+---------------------------+--------------------------------------+
| 5 | ATC-TF-ER-0001            | *ATLAS Cavern Magnetic field         |
|   |                           | Calculations*                        |
+---+---------------------------+--------------------------------------+
| 6 | \[pp                      | *Circuit schematic, PP3 Version 3.0* |
|   | 3\]/pcb/v3.0/PP3_V3.0.pdf |                                      |
+---+---------------------------+--------------------------------------+
| 7 | \[pp3\                    | *Bill of Materials, PP3 Version 3.0* |
|   | ]/pcb/v3.0/PP3_BOM_04.txt |                                      |
+---+---------------------------+--------------------------------------+
| 8 | \[pp3\]/magnetic_shie     | *A study of choke core saturation    |
|   | lding/NO_SHIELD_TESTS.DOC | with field strength*                 |
+---+---------------------------+--------------------------------------+
| 9 | \[pp3\]/magnetic_shieldin | *A study of choke P0422 core         |
|   | g/P0422_INDUCTOR_TEST.DOC | saturation with field*               |
+---+---------------------------+--------------------------------------+
| 1 | \[pp3\]/magnetic_s        | *PP3 magnetic shield performance --  |
| 0 | hielding/SHIELD_TESTS.DOC | high-field measurements in           |
|   |                           | Melbourne*                           |
+---+---------------------------+--------------------------------------+
| 1 | \[pp3\]/magnetic_s        | *PP3 magnetic shield performance --  |
| 1 | hielding/shieldtests2.xls | low-field Helmholtz measurements*    |
+---+---------------------------+--------------------------------------+
| 1 | \[pp3\]/magnetic_         | *PP3 magnetic shield performance --  |
| 2 | shielding/shieldtest1.xls | preliminary strong field             |
|   |                           | measurements at CERN*                |
+---+---------------------------+--------------------------------------+
| 1 | \[pp3\]/docs/power.txt    | *PP3 power dissipation estimates*    |
| 3 |                           |                                      |
+---+---------------------------+--------------------------------------+
| 1 | \[pp3\]/docs/20021        | *PP3 voltage limiter temperature     |
| 4 | 004_steve_testresults.txt | dependenc*e                          |
+---+---------------------------+--------------------------------------+

[^1]: Conec Corporation, Brampton, Ontario, Canada;
    http://www.conec.com/

[^2]: FCT Electronic Gmbh, München, Germany;
    http://www.fct-electronic.de/

[^3]: Pulse Engineering, San Diego, California; http://www.pulseeng.com/

[^4]: RFI Indiustries Pty Ltd,
    [www.rfi-ind.com.au](http://www.rfi-ind.com.au/),

    52 Holloway Drive, Bayswater 3153, Victoria, Australia, +61 3 9762
    6733

[^5]: Electrical isolation process yet to be finalised.

[^6]: The cable backshells at PP3 on both the type III and type IV cable
    may be the same as those used on the macro-assembly power cables
    purchased by Oxford. These are model number FKC4G from the FCT
    München company. These backshells fit within a volume 19 mm high, 72
    mm wide and 58 mm deep. They are black plastic, fitted with long
    jack-screws for improved accessibility. An alternative model from
    FCT, FKC4GA, has the same dimensions but with metalised external
    coating. It is not proposed to use the metalised version due to the
    requirement for safety isolation.

[^7]: The length of the PCB version 3.0 and two cable FKC4G backshells
    together is 201 mm.

[^8]: CERN Stores SCEM 06.61.77.100.8, Racks for LHC Experiments.