![](media/image1.png){width="2.1770833333333335in"
height="0.3958333333333333in"}

[1. [Overview]{.smallcaps} 3](#__RefHeading___Toc98898187)

[[2.]{.smallcaps} [Q1 through Q5 Quadrupole Magnets -- WBS
2.1.1]{.smallcaps} 3](#__RefHeading___Toc98898188)

[**2.1** **Cold Mass -- WBS 2.1.1.1** 4](#__RefHeading___Toc98898189)

[[2.1.1]{.smallcaps} [Iron Yoke]{.smallcaps}
5](#__RefHeading___Toc98898190)

[[2.1.2]{.smallcaps} [Quadrant Splice Assembly]{.smallcaps}
6](#__RefHeading___Toc98898191)

[[2.1.3]{.smallcaps} [Bus Bar Layout]{.smallcaps}
6](#__RefHeading___Toc98898192)

[[2.1.4]{.smallcaps} [Superconductor Procurement]{.smallcaps}
7](#__RefHeading___Toc98898193)

[[2.1.5]{.smallcaps} [Tooling Modifications]{.smallcaps}
8](#__RefHeading___Toc98898194)

[[2.1.6]{.smallcaps} [Schedule]{.smallcaps}
8](#__RefHeading___Toc98898195)

[**2.2** **Cryostat -- WBS 2.1.1.2** 9](#__RefHeading___Toc98898196)

[[2.2.1]{.smallcaps} [Layout]{.smallcaps}
9](#__RefHeading___Toc98898197)

[[2.2.2]{.smallcaps} [Suspension System]{.smallcaps}
10](#__RefHeading___Toc98898198)

[[2.2.3]{.smallcaps} [Schedule]{.smallcaps}
12](#__RefHeading___Toc98898199)

[**2.3** **MTF Test Stand (Stand-6) -- WBS 2.1.1.3**
14](#__RefHeading___Toc98898200)

[[2.3.1]{.smallcaps} [Test Stand Design]{.smallcaps}
14](#__RefHeading___Toc98898201)

[[2.3.2]{.smallcaps} [Schedule]{.smallcaps}
16](#__RefHeading___Toc98898202)

[**2.4** **Quadrupole Fabrication & Test -- WBS 2.1.1.4**
17](#__RefHeading___Toc98898203)

[[3.]{.smallcaps} [New Spools -- WBS 2.1.2]{.smallcaps}
17](#__RefHeading___Toc98898204)

[**3.1** **HTS Leads -- WBS 2.1.2.1** 18](#__RefHeading___Toc98898205)

[[3.1.1]{.smallcaps} [Test Results]{.smallcaps}
18](#__RefHeading___Toc98898206)

[[3.1.2]{.smallcaps} [Procurement Strategy]{.smallcaps}
19](#__RefHeading___Toc98898207)

[[3.1.3]{.smallcaps} [Schedule]{.smallcaps}
19](#__RefHeading___Toc98898208)

[**3.2** **Corrector Magnets -- WBS 2.1.2.2**
20](#__RefHeading___Toc98898209)

[[3.2.1]{.smallcaps} [Schedule]{.smallcaps}
20](#__RefHeading___Toc98898210)

[**3.3** **Spool Assembly -- WBS 2.1.2.3**
21](#__RefHeading___Toc98898211)

[[3.3.1]{.smallcaps} [Design Status]{.smallcaps}
21](#__RefHeading___Toc98898212)

[[3.3.2]{.smallcaps} [Schedule]{.smallcaps}
24](#__RefHeading___Toc98898213)

[]{#__RefHeading___Toc98898187 .anchor}**1. [Overview]{.smallcaps}**

Technical Division starting working on BTeV in October 2003 after the
project got P5 approval with a recommendation to build a new C0 IR
interaction region. The Division was responsible to design, fabricate
and test superconducting quadrupole magnets, Q1 through Q5, and new
cryogenic utility assemblies ("spool pieces") that were to be installed
at C0 in the Tevatron. Figure 1 shows the overall organization of the
project.

***Figure 1**: TD BTeV C0 IR Organization*

An overview of the C0 IR project is presented in the "Design Report for
the C0 IR" -- BTeV Document #2497. The project requires 10 quadrupole
magnets, five on either side of the interaction region with an
additional five spares. Three different types of spools, X1, X2 and X3
were also part of the project. Spools typically contain the magnetic
correction system, High Temperature Superconductor (HTS) and
conventional power leads, beam position monitors and all necessary
interfaces. The project required 10 spools (4 each of X1 and X2 type and
2 of X3 type) with an additional 3 spares.

The C0 IR project was terminated in February 2005. This report outlines
various tasks that were accomplished between October 2003 and time of
close out.

[]{#__RefHeading___Toc98898188 .anchor}**[2. Q1 through Q5 Quadrupole
Magnets -- WBS 2.1.1]{.smallcaps}**

The magnet design is based on the LHC IR quadrupole with the length,
iron yoke, cryostat, cryogenic system, and interconnects modified for
the C0 IR. Table 1 shows the locations, gradient, magnetic length and
mechanical slot length requirements for quadrupole magnet assemblies.

***Table 1**: Magnet Parameters*

![](media/image4.wmf)

[]{#__RefHeading___Toc98898189 .anchor}**[2.1 Cold Mass -- WBS
2.1.1.1]{.smallcaps}**

The cold mass (Figure 2) consists of a 2-layer NbTi coil with one wedge
per layer and G-11 end-parts. The inner and outer cable and the wedges
are insulated with Kapton film. The coil package is supported in the
straight section by Nitronic-40 collars which are locked with two keys
in each quadrant. The collars are stamped and pre-assembled into 37 mm
long packs and thus provide required rigidity for the coils. Over the
ends, quadrant blocks and aluminum end cans are used to provide the
pre-stress. A two piece iron yoke provides flux return. The collared
coil is aligned within the yoke by four non-magnetic keys. The entire
assembly is surrounded by a stainless steel skin which is welded to
stainless steel alignment keys. These keys also act as a mechanical
fiducial used in the alignment measurements. End-plates are welded on to
the skin and act as anchor points for the end-cans thus providing axial
support for the coils and attachment points for the quadrant lead splice
block and end-domes.

![](media/image5.wmf){width="4.052777777777778in"
height="4.038888888888889in"}

***Figure 2**: Cross-section through the straight section of the
cold-mass.*

The following are the design changes with respect to the LHC IR
quadrupole design --

-   Yoke diameter and features

-   Quadrant splice assembly

-   Bus & expansion loop

-   Axial restraint system

-   End plate & end domes

-   Shell thickness, 6.35 mm

-   Beam tube, 1.65 mm wall

At the time of close out, the yoke design, quadrant splice assembly and
bus bar design were completed. The detailing of axial restraint system
had just begun. Other aspects that required considerable attention
included updating the NbTi superconductor strand and cable
specifications, preparing request for proposal's (RFP's) for Kapton^®^
insulation and quadrupole collar steel.

[]{#__RefHeading___Toc98898190 .anchor}*[2.1.1 Iron Yoke]{.smallcaps}*

The yoke diameter, and hence the overall cryostat size, was reduced such
that the height of the beam above the tunnel floor in the Tevatron could
be accommodated without any civil construction in the tunnel. The final
dimensions of the iron yoke are shown in Figure 3. Note that the
channels in the iron yoke were provided for power and instrumentation
cables as well as for helium flow. Thermal analysis indicated that the
area of these channels was adequate for cooling purposes. Magnetic
calculations based on the new iron yoke dimensions were also completed
and the harmonics were found to be acceptable.

![](media/image6.jpeg){width="6.9944444444444445in"
height="3.6444444444444444in"}

***Figure 3**: Final dimensions of the iron yoke*

[]{#__RefHeading___Toc98898191 .anchor}*[2.1.2 Quadrant Splice
Assembly]{.smallcaps}*

The quadrant splice assembly was redesigned to fit within the reduced
overall magnet diameter. The splice assemblies were turned 90^o^ with
respect to the previous design to gain some space. Figure 4 shows the
proposed design for the quadrant splice assembly. Note that the quadrant
splices are now in the direction of the beam.

![](media/image7.png){width="2.738888888888889in"
height="2.9569444444444444in"}

***Figure 4**: Quadrant splice assembly layout*

[]{#__RefHeading___Toc98898192 .anchor}*[2.1.3 Bus Bar
Layout]{.smallcaps}*

The bus bar is made of C0 IR superconducting inner cable paired with the
same style cable made of pure copper. The bus insulation must be robust
and has to withstand a voltage of 1000V to ground and to the adjacent
bus. As shown in the Figure 3, there are 8 rectangular slots, each 9.8
mm x 18.5 mm, in the iron. The estimated total cross-section of the bus
is less than 9 mm x 18 mm, which will fit within one of the slots.
Figure 5 shows the proposed bus layout for the inner triplet (Q1-Q2-Q3)
magnets.

![](media/image8.png){width="6.988888888888889in"
height="2.5701388888888888in"}

***Figure 5**: Bus bar layout for inner triplet, Q1-Q2-Q3 magnets.*

An expansion loop is needed to accommodate shrinkage of the bus during
cool-down. Figure 6 shows the proposed expansion loops in Q2. Similar
arrangements will be made for all the magnets.

![](media/image9.wmf){width="4.618055555555555in"
height="3.265277777777778in"}

***Figure 6**: Proposed expansion loop and bus layout for Q2 magnet
(lead end is shown here).*

[]{#__RefHeading___Toc98898193 .anchor}*[2.1.4 Superconductor
Procurement]{.smallcaps}*

The approach taken for the superconductor procurement sought to avoid
some of the problems, such as mechanically unstable cable, encountered
during the LHC IR quadrupole fabrication. Attempts were made to
determine if the mechanical instabilities encountered in some cables
could be correlated with factors such as spring back value and strand
manufacturers. In the end, it was decided that cable would be procured
directly from the vendor and that the vendor would be responsible for
the stability of the cable. A test to verify the mechanical stability of
the cable was added as a part of the QC requirements. Furthermore,
vendor selection would incorporate their recent performance in NbTi
fabrication. Lastly the procurement was to be split into two phases.
Phase I would be a short production run (\< 10% of the total quantity)
to test the cable and wind a few coils. This was expected to take 5 to 6
months from the date of signing the contract. Phase II was to be the
remainder of the conductor required. Note that Phase II was to be set as
an Option that will be automatically executed if the vendor successfully
completed Phase I.

The specifications were revised and updated considerably, removing all
references to SSC documents, and restructuring them to form a coherent
set of documents. The QA plan suggested in the earlier specifications --
which was written during SSC times - was removed and instead required
the vendor to provide a QA plan which would be mutually agreed upon. The
tolerances on the cable width and residual twist were tightened (in line
with LHC Dipole strand specifications) and new tests such as eddy
current testing and sharp edge testing were added. The following
documents formed part of the specification package:

-   5500-ES-371014 BTeV C0 IR Quadrupole Magnet Inner and Outer Cable
    Manufacturing Spec

-   5500-ES-371009 BTeV C0 IR Quadrupole Magnet Inner Strand
    Specification

-   5500-ES-371010 BTeV C0 IR Quadrupole Magnet Outer Strand
    Specification

-   5500-ES-371015 BTeV C0 IR Quadrupole Magnet NbTi Alloy Bars and Rods
    Spec.

-   5500-ES-371016 BTeV C0 IR Quadrupole Magnet Nb Barrier Material
    (Reactor Grade I) Spec.

-   5520-MA-439043 BTeV C0 IR Quadrupole Magnet Inner Bare Cable drawing

-   5520-MA-439044 BTeV C0 IR Quadrupole Magnet Outer Bare Cable drawing

    []{#__RefHeading___Toc98898194 .anchor}*[2.1.5 Tooling
    Modifications]{.smallcaps}*

The following tolling modifications were anticipated for C0 IR
quadrupoles:

-   Winding station and mandrel modifications to wind coils with
    different lengths

-   Curing mold modification to accept different coil lengths,

-   Yoke lifting fixture; and,

-   Welding contact tooling.

At the time of project termination, the winding station and mandrel
modifications were being worked on. A single mandrel that can be used to
wind different coil lengths was proposed and layouts for such a design
were completed.

[]{#__RefHeading___Toc98898195 .anchor}*[2.1.6 Schedule]{.smallcaps}*

Figure 7 shows the proposed schedule for WBS 2.1.1.1. Most of the
activities were on track at the time of project termination, except for
tooling design modifications which were about one month behind the
schedule (due to higher priority jobs such as 'Shut Down' activities
associated with the Tevatron in December 2004). The design and
procurement activities were supposed to be completed by July 2006.

![](media/image10.jpeg){width="6.097222222222222in" height="4.16875in"}

***Figure 7**: Proposed schedule for Cold Mass component and tooling
design and procurement*

[]{#__RefHeading___Toc98898196 .anchor}**[2.2 Cryostat -- WBS
2.1.1.2]{.smallcaps}**

The cryostat consists of all components of the quadrupole assembly
except for the magnet itself. It serves to support the magnet accurately
and reliably within the vacuum vessel, provides all required cryogenic
piping, and provides thermal insulation. The major components of the
cryostat are the vacuum vessel, thermal shield, multi-layer insulation,
cryogenic piping, suspension system and interconnection components.

[]{#__RefHeading___Toc98898197 .anchor}*[2.2.1 Layout]{.smallcaps}*

The layout of the magnet assemblies was completed first to ensure that
we have adequate space in the C0 building as well as agree with the
detector layout. The interface requirements were also finalized. All the
BTeV / C0 IR quadrupoles share Tevatron cryogenics, i.e. 1Ø, 2Ø, and LN2
shield circuits. Q1 through Q3 magnets have returns for each of the
cryogenic circuits. The interface layouts for Q1 through Q3 are not
required to be identical to the Tevatron. However, for simplicity, most
of the bellows, flanges, and seals are common to all magnets. The Q4 and
Q5 magnets were to connect to existing Tevatron dipoles so their
interconnect interfaces are identical to those magnets. Figure 8 shows
Q2 and Q3 outline and interface layouts. The cross-sectional layouts of
all the cryostat assemblies have also begun at the time of project
termination. Q2 was in most advanced stage and Figure 9 shows the
layout.

![](media/image11.png){width="7.398611111111111in"
height="3.2583333333333333in"}

> ***Figure 8**: Q2 and Q3 outline and interface dimensions*

![](media/image12.png){width="7.206944444444445in"
height="4.386111111111111in"}

***Figure 9**: Q2 non-IP end view*

[]{#__RefHeading___Toc98898198 .anchor}*[2.2.2 Suspension
System]{.smallcaps}*

The suspension system will provide both the structural support and
thermal insulation for the cold mass within the cryostat assembly. The
design of the system included determining the fundamental frequencies of
the suspended cold mass system and perturbing frequencies present in the
environment where the magnets will be installed. A LHC HGQ model magnet
was suspended in C0 main assembly building using an existing suspension
system to measure the vibration and ground motion. Figure 10 shows the
test set up. More details on the test set up can be found in the TD
tech-note, TD-05-018. Three concrete shielding blocks make up the test
stand structure. Care was taken to level these blocks.

Ground motion was measured about one hour per session for two sessions.
Figure 11 (a) shows the data for one of the sessions. Note that the
resonating frequencies were18, 29.7 and 59.5 Hz. The magnet was then
taped either in longitudinal or transverse direction to measure
perturbed frequencies. Both showed similar resonating frequencies and
Figure 11 (b) shows the data for the longitudinal excitation. The first
four natural frequencies were 5.5, 18. 25.5, 29.7 Hz.

Finite Element analysis was also performed to understand the resonating
frequencies and to evaluate the fiberglass damping coefficient. The work
was still in progress when the project was terminated.

![](media/image13.jpeg){width="2.9694444444444446in"
height="4.157638888888889in"}

**Figure 10**: *Test step-up at the C0 main assembly building*.

![](media/image14.jpeg){width="3.998611111111111in"
height="3.4138888888888888in"}

**Figure 11(a)**: *Ground Motion. Traces color. Black: accelerometer on
magnet, longitudinal mode; blue: accelerometer on magnet, transversal
mode; red: accelerometer on the floor, vertical mode.*

![](media/image15.jpeg){width="3.4472222222222224in"
height="2.9604166666666667in"}
![](media/image16.jpeg){width="3.4472222222222224in"
height="2.9541666666666666in"}

**Figure 11(b)**: *Response to a longitudinal perturbation (both
directions).*

[]{#__RefHeading___Toc98898199 .anchor}*[2.2.3 Schedule]{.smallcaps}*

Figure 12 shows the proposed schedule for cryostat design and
procurement. At the time of project termination, the design and
detailing vacuum vessels had been completed (see Figure 12(b) for the
parts tree). The suspension design and analysis was being worked when
the project got terminated.

![](media/image17.jpeg){width="7.040277777777778in"
height="4.509027777777778in"}

***Figure 12**: Cryostat design and procurement schedule*

![](media/image18.wmf){width="9.38888888888889in"
height="4.141666666666667in"}

**Figure 12(b)**: *Parts Tree for the Cryostat Vacuum Vessel*

[]{#__RefHeading___Toc98898200 .anchor}**[2.3 MTF Test Stand (Stand-6)
-- WBS 2.1.1.3]{.smallcaps}**

A new stand in the Magnet Test Facility (MTF) was required for the
testing of the C0 IR quadrupoles for a number of reasons:

-   The existing Tevatron stands were limited by the feed box bus and
    current leads to about 6 kA maximum. C0 IR quads require 10 kA.

-   The C0 IR inner triplet quads will have an interconnect
    significantly different from the standard Tevatron interconnect.

-   Like the present B0 and D0 final focus magnet systems, the cryogenic
    circuits are "folded back" to the feed box to bring all the valves
    back out of the interaction region. Thus, the test feed box needs to
    include not only extra pipes but JT valve and cooldown value (which
    are normally in the turnaround box).

There are two remaining Tevatron test stands in operation at MTF: Stand
2 and Stand 6. Stand 2 is on the north side of the cryogenic
distribution system and faces conventional magnet test stand B; Stand 6
is on the south side of the distribution system and had been extended to
a length of twice that of Stand 2. Stand 4, also on the south side of
the distribution system, is the LHC test stand and it is fundamentally
different from what is needed for Tevatron magnets. It was designed for
pool boiling 4.4 K helium or 1 atmosphere subcooled stagnant helium. In
particular, Stand 4 does not have a Tevatron-style circuit with JT valve
and 2-phase return flow. Stand 6 was the obvious choice since it had a
Tevatron cryogenic interfaces and allowed greater access for large
magnets.

[]{#__RefHeading___Toc98898201 .anchor}*[2.3.1 Test Stand
Design]{.smallcaps}*

The new Stand 6 will be able to test five quadrupole magnets (Q1-Q5) and
the X3 spool at temperatures from a minimum of 3.8 K to about 4.5K.
Stand 6 will have to accommodate C0-IR magnets of three different
interconnect configurations: one for the BTeV-style Q2 and Q3 magnets
and the X3 spool at their IP-ends, one for the BTeV-style Q1 magnet at
its lead end, and one for the Tevatron-style Q4 and Q5 magnets. The
stand will have two conventionally-cooled 10kA leads. The maximum
allowable pressures for the piping in the stand are 200 psig for
single-phase helium, 50 psig for the two-phase helium and 100 psig for
nitrogen. For the helium supply the pressure range is 1.8 -- 2.2 bar,
the temperature range is 3.8 -- 4.6K and the flow rate is 15 -- 35
g/sec. The saturated nitrogen vapor flow rate is 10 g/sec. The design of
the feed box and its components follow the pressure vessel rules listed
in the FESHM.

A three-dimensional solid model has been created, detailing the layout
of the piping, the layout of the 80K thermal shield, the design of the
vacuum vessel, the design of the turnaround box, and the designs of the
interconnects to the magnet (Figure 13). Engineering drawings for the
vacuum vessel, the helium vessel, the thermal shield, the piping layout,
and the piping and instrumentation exist in detailed form (drawing
numbers 1670-MD-418214 and 1670-MD-418250 through 1670-MD-418273).
Engineering notes for the vacuum vessel, the helium vessel, the pressure
drop and sizing of the piping, and thermal shield are complete. The test
stand successfully went through a conceptual design review held on
January 26, 2005.

![](media/image19.png){width="6.061111111111111in"
height="5.466666666666667in"}

***Figure 13**: 3D model of Stand 6 feed box --* *the front halves of
the vacuum vessel and 80K thermal shield are hidden for viewing inside
of the feed box. The interconnect shown is for the Q2 and Q3 magnets*

The following are the some of the new features in the test stand design
--

-   *Helium Vessel* -- A rectangular helium vessel with an access from
    the bottom to remove power leads has been implemented. This feature
    will help in installation and maintenance. Note that the vessel has
    been designed per ASME pressure vessel code requirements.

-   *Power Leads* -- American Magnetics Inc. proposed a design for the
    10 kA power leads meeting our preliminary requirements. The leads
    will have round top instead of a flag to avoid interference with
    other items on the top plate. The length of the leads will be 8
    inches longer so that the leads sit in the helium bath. Finally the
    diameter of leads will be increased from 2.125 in to 2.5 in. Figure
    14 shows the proposed lead design.

-   *Insulating Sleeve for Power Leads*: An additional insulating sleeve
    above the top plate will be installed to minimize the heat leak into
    the chimney. This feature exists in Stand -- 4 and VMTF but not in
    the existing Stand -- 6 design.

![](media/image20.jpeg){width="5.397222222222222in"
height="4.142361111111111in"}

> ***Figure 14**: New 10 kA power leads design proposed by AMI.*

[]{#__RefHeading___Toc98898202 .anchor}*[2.3.2 Schedule]{.smallcaps}*

Figure 15 shows the proposed schedule for Stand -- 6 design,
procurement, installation and commissioning. At the time of closing the
feed box design was 40% complete and Adaptors / End-Cap were 25%
complete.

![](media/image21.jpeg){width="6.525in" height="3.4305555555555554in"}

***Figure 15**: Stand -- 6 schedule*

[]{#__RefHeading___Toc98898203 .anchor}**[2.4 Quadrupole Fabrication &
Test -- WBS 2.1.1.4]{.smallcaps}**

The fabrication of quadrupoles was scheduled to begin in July of 2006.
The duration for the tasks reflects the time that is taken to fabricate
LHC IR quadrupole production magnets. Figure 16 shows the proposed
schedule for fabrication and test of quadrupoles.

![](media/image22.jpeg){width="7.027777777777778in"
height="4.499305555555556in"}

***Figure 16**: Q1 through Q5 quadrupole fabrication and test schedule*

[]{#__RefHeading___Toc98898204 .anchor}**[3. New Spools -- WBS
2.1.2]{.smallcaps}**

Three different types of spool assemblies, X1, X2, and X3 are needed to
account for different correction schemes at various locations along the
interaction region (IR). Table 2 lists the different spool designs with
corresponding corrector magnets and required maximum gradients, allotted
slot lengths and necessary power leads.

***Table 2**: Elements in different spool designs. Field values listed
are the maximum required. "SL" designates safety leads.*

[]{#__RefHeading___Toc98898205 .anchor}**[3.1 HTS Leads -- WBS
2.1.2.1]{.smallcaps}**

10 kA current leads made from High Temperature Superconductor (HTS) will
be used to power the quadrupoles in the C0 IR to avoid additional
loading of the 4.5 K He system. Note that in the current Tevatron, four
spool pieces have been modified to incorporate 5 kA HTS leads, and one
of these has been installed and operated in the ring for several years.
Fermilab still has 7 pairs of HTS leads in inventory from a Tevatron
upgrade program and the proposal was to test these leads to see if they
could carry required the 10 kA current required for the C0 IR
quadrupoles.

[]{#__RefHeading___Toc98898206 .anchor}*[3.1.1 Test
Results]{.smallcaps}*

Three pairs of HTS leads were tested and ran successfully at or above
the nominal C0-IR operating current before the project was terminated.
The first test was of leads installed in a Tevatron spool; the
subsequent tests were conducted in a very controlled environment
(cryogenic pressure, temperature and flow) to understand various
operating parameters of the leads. These tests revealed that both the
upper HTS and conventional copper section which are cooled with liquid
nitrogen and the lower HTS section cooled with liquid helium vapor
exhibited stable operation up to 10 kA and repeated current ramps from 0
to 200 A/s. Figure 17 shows a summary plot of the current and the Cu and
HTS section voltages for one of these tests. The leads were stable for
more than 5 hours at the nominal operating current of 9560 A followed by
continuous ramping from 0A to 9560 A to 0A at a ramp rate of 200 A/s for
nearly an hour.

![](media/image23.png){width="5.383333333333334in" height="4.81875in"}

***Figure 17**: HTS Lead test: 5 hours of stable DC operation at 9560A,
followed by roughly one hour of ramping 0 - 9560 - 0 at 200 A/sec*.

[]{#__RefHeading___Toc98898207 .anchor}*[3.1.2 Procurement
Strategy]{.smallcaps}*

C0 IR project required 13 HTS lead pairs that can carry 10 kA of
current. The strategy was to use all the existing spare Tevatron leads
(seven in total) and procure 6 additional leads with identical
interfaces. Specifications and interface drawings were being worked on
at the time of close out.

Two companies, IGC and HTS-110 had shown interest in fabricating 10 kA
HTS leads. Note that ASC, the supplier of HTS leads for the Tevatron
upgrade program, sold its HTS technology to HTS-110, a New Zeeland based
company.

[]{#__RefHeading___Toc98898208 .anchor}*[3.1.3 Schedule]{.smallcaps}*

Figure 18 shows the proposed schedule for HTS leads procurement and
testing. The goal was to finish writing specifications by May 05, send
out RFP's in the last quarter of FY05 and be ready to place the contract
early FY06. At the time the project got terminated, first draft of
specifications was completed.

![](media/image24.jpeg){width="6.990277777777778in"
height="3.265277777777778in"}

**Figure 18**: *Proposed schedule for HTS leads procurement and testing*

[]{#__RefHeading___Toc98898209 .anchor}**[3.2 Corrector Magnets -- WBS
2.1.2.2]{.smallcaps}**

It was decided early on in the project to pursue a source outside of
Fermilab to provide the corrector magnets to be installed in the C0-IR
spools. Various proposals from Brookhaven National Laboratory, the
Institute of High Energy Physics (Protvino), the Center for Advanced
Technology (India) and CERN were evaluated in terms of cost, schedule
and ability to meet requirements. Based on their ability to meet a tight
schedule, as well as the ability to meet all field quality requirements,
BNL was selected to provide the corrector magnets.

A Memorandum of Agreement (MOA) was signed between Fermilab and BNL in
the first week of February, 2005 to make 16 corrector magnet assemblies
including 6 spares.

[]{#__RefHeading___Toc98898210 .anchor}*[3.2.1 Schedule]{.smallcaps}*

Figure 19 shows the BNL proposed schedule for corrector fabrication.
Note that the start date was moved to April, 2005 per BTeV management
expectation that the project could get CD-3a approval by then. The first
corrector magnet was scheduled to be shipped to Fermilab in January
2006.

At the time of close out, the following activities were completed at BNL
--

-   Conceptual designs existed for all coils that met the operating
    current requirement of ≤ 100A.

-   Fully 3D "air coil" field calculations were done with existing BNL
    design codes. Yoke contribution was estimated by scaling from 2D
    with & without iron.

-   Software development was underway to automatically import winding
    information into VF Opera3d code (Tosca) to do full 3D field
    calculations with iron.

-   Preliminary design solutions had been completed and were to be
    iterated and optimized for the final designs.

-   Discussions with Fermilab of technical (power supply, quench
    protection etc.) and other interface issues were in progress.

![](media/image25.wmf){width="6.804166666666666in"
height="5.052083333333333in"}

***Figure 19**: BNL proposed schedule for corrector fabrication*

[]{#__RefHeading___Toc98898211 .anchor}**[3.3 Spool Assembly -- WBS
2.1.2.3]{.smallcaps}**

[]{#__RefHeading___Toc98898212 .anchor}*[3.3.1 Design
Status]{.smallcaps}*

Figure 20 shows the latest version of the X2 spool assembly. Note that
X2 design was furthest along when the project got terminated. The helium
vessel is supported inside the vacuum vessel using two suspension posts
identical to the ones used in the cryostat to support the quadrupole
cold mass. The corrector magnet will be supported inside the helium
vessel with two stainless steel rings. Once the corrector is aligned
inside the helium vessel, the rings will be welded to the inside of the
helium vessel to lock it in place. The corrector support rings will be
coincident with the suspension posts. Unlike the X2 and X3 spools, there
are no HTS power leads in X1 spools. Hence the outer vacuum vessel
houses only the helium vessel that contains corrector package and the
necessary interfaces. BPM's will be embedded in the spool between
flanges and the corrector magnet. The allotted slot length for BPM's is
10 inches. The BPM design will be similar to those already installed in
the Tevatron. Figures 21 and 22 shows the cross-section of the spool
assembly through the corrector magnet and lead stack assembly
respectively.

![](media/image26.jpeg){width="5.495138888888889in" height="4.2625in"}

***Figure 20**: Isometric view of X2 spool assembly layout*

![](media/image27.png){width="6.429166666666666in"
height="3.6666666666666665in"}

***Figure 21**: Cross-sectional view of X2 spool assembly through
corrector magnet*

![](media/image28.png){width="4.929166666666666in"
height="3.6152777777777776in"}

***Figure 22**: Cross-section of the X2 spool lead stack assembly*

The spool design has evolved over time to what was presented in Figure
20. Note the reason for moving from a cylindrical outer vacuum vessel to
a square one was to meet tunnel clearance requirements. Figure 23 shows
the clearances available in the tunnel with the latest design.

![](media/image29.png){width="3.9875in" height="3.857638888888889in"}

***Figure 23**: Tunnel cross-section with new spool piece showing the
clearance available.*

[]{#__RefHeading___Toc98898213 .anchor}*[3.3.2 Schedule]{.smallcaps}*

Figure 23 shows the proposed schedule for spool assembly design,
procurement and testing. The working model was to design the spool
assembly in-house, fabricate them outside and then cold-test the
completed spool assembly at Fermilab. At the time of close out, 15% of
the design work was completed. The fabrication of the first spool
assembly was to start in October 06. A preliminary fabrication study,
which was contracted to 6 vendors, indicated that the proposed
fabrication schedule for the spool assemblies was feasible - one year
for the first spool followed by 1 spool per month.

![](media/image30.jpeg){width="6.965277777777778in"
height="3.8291666666666666in"}

***Figure 23**: Spool assembly design, procurement and test schedule*