THIS SHOULD BE INSERTED FIRST AND REPLACES THE SUBSECTIONS UNDER
STABILITY PERFORMANCE. Insert on \"sealed-tube\": results should follow
in each subsection.

#### Thermal Effects

The out-of-plane deflection of aluminum-tube prototype #4 was measured
by cooling the sector in cold box without coolant flow. Optical targets
located on the sector were viewed by an optical CMM. A temperature
change of 40^o^C(from 22^O^C to -18^o^C) resulted in out-of-plane motion
of less than ±0.020 mm relative to the location at room temperature. The
in-plane motion is negligible for a single sector well supported by the
three support points. Similar distortion measurements were performed on
prototype #3 before and after irradiation, and the differences were
within measurement errors. These measurements have been done with dummy
heaters attached only with CGL-7018 or without heaters.

#### Pressure Effects

The distortions caused by pressure have been evaluated on aluminum-tube
prototypes #4 and #6. Many points on prototype #6 were measured - see
Figure 1. Data were taken up to about 5 bar absolute and after cycling
140 times to 5 bar absolute. The distortions in the \"wing\" regions on
either side of the sector are the greatest. Distortions at the worst
points are plotted in Figure 2. There is clear evidence of a permanent
distortion (in the worst case about 40 microns). The magnitude of the
distortion vs pressure is reduced after the initial distortion. The
maximum distortion over most of the sector, not including the wing
regions was less than 15 microns even at 7 bar absolute. Dummy heaters
were mounted on this sector and the thermal performance easily met
requirements, as already described above. The permanent distortions are
attributable to distortions in the aluminum tube(confirmed by direct
measurements of a bare tube). These results are (just) acceptable.
Prototypes 7-10 have a thicker tube wall (0.029 mm rather than 0.020 mm)
and will be tested, and should exhibit less distortion. Prototype #4 was
tested to 5 bar absolute in a similar manner at -7^o^C and showed
similar distortions.

+-----------------------------------+-----------------------------------+
| ![](media/image1.j                | ![](media/image2                  |
| peg){width="3.5555555555555554in" | .wmf){width="3.173611111111111in" |
| height="2.6666666666666665in"}    | height="2.7118055555555554in"}    |
|                                   |                                   |
| Figure 1. Prototype #6 showing    | Figure 2. Distortion vs pressure  |
| points measured during pressure   | at worst points before and after  |
| testing.                          | pressuring cycling(see text).     |
+-----------------------------------+-----------------------------------+

#### Dynamic Motion

Some measurements of the dynamic response of prototype aluminum-tube
sectors has been measured using TV holography. The sector is firmly
attached at the three support points and driven by a piezoelectric
oscillator and the fringe pattern observed. This was done on prototype#3
before and after irradiation and the results are shown in Figure 3. The
frequency response (of a single sector) is well above our nominal 100 Hz
requirement.

+-----------------------------------------------------------------------+
| ![](media/image3.wmf){width="6.497916666666667in"                     |
| height="4.190972222222222in"}                                         |
|                                                                       |
| Figure 3. Frequency response of a prototype aluminum-tube sector      |
| before and after irradiation to 22 MRad.                              |
+-----------------------------------------------------------------------+

#### Transient and Fault Conditions

Distortion measurements on aluminum-tube sectors after 7 bar absolute
pressure have already been described. No distortion measurements have
been made yet after a loss-of-coolant fault condition.

### Prototype Disk

![](media/image4.jpeg){width="4.555555555555555in"
height="3.4166666666666665in"}

Figure 4. Prototype disk with 12 ESLI sectors in optical CMM. Cover of
environmental box has been removed.

A complete disk of 12 sectors manufactured by ESLI was assembled and
tested. Each sector had six dummy heaters. The sectors were attached to
a prototype support ring designed by Hytec, Inc and fabricated by
Allcomp, Inc. The disk-support ring was attached to an Invar support
triangle at three points, which simulates the mounting expected in
ATLAS. Coolant and power connections were made and the entire assembly
placed in an environmental box on the table of an optical CMM as shown
in Figure 4.

![](media/image5.png){width="5.1875in" height="3.25in"}

Figure 5. IR image of the disk prototype operated at 60W per sector. The
inlet cooling temperature was 11^O^C. Two sectors were not
powered(leaked).

Thermal measurements were made of the complete disk and are shown in
Figure 5 for completeness.

Stability measurements were made by attaching optical targets to each
sector (four locations), to the supporting ring and to the Invar
support. The location of the targets is shown in Figure 6.

![](media/image6.png){width="6.496527777777778in"
height="5.020138888888889in"}

Figure 6. Location of optical targets on prototype disk.

Temperatures on each sector and pressures were also recorded. The
optical CMM was programmed to find and record the target locations.[^1]
Measurements were taken at different coolant temperatures down to
-10^O^C. The distortions from temperature or pressure changes in the
plane of the disk(X and Y) and out-of-plane(Z) were measured for each
sector and for the ring. These extensive measurements are briefly
summarized here.[^2]

Distortions are determined by comparing the locations of the targets to
an average base state taken at room temperature and no flow. A typical
example of distortions observed at 60W per sector and at -10^0^C are
summarized in Figure 7. AVE is the average motion between the two
states, SPREAD is the largest motion-smallest motion(including sign) and
RMS is the standard deviation. The results are tabulated for different
locations on the disk: on the ring, on a few coolant
connections(in/out), at the outer radius of sectors(mount), the inner
radius of sectors and the Invar support, which should not move. The
largest distortions are in the Z(out-of-plane) motion but are well
within requirements. In-plane motions are a few microns, also within the
requirements. Although ESLI sectors are no longer considered for
production, these measurements are indicative of the stability
performance expected for a complete disk. \*\*More here later\*\*\*

![](media/image7.wmf){width="4.09375in" height="3.6006944444444446in"}

Figure 7. Example of distortions measured at -10^o^C and 60W as
explained in the text. Units are mm.

[^1]: The measurement procedure may be seen at
    http://www-atlas.lbl.gov/mov/Proto_Disk_video.html.

[^2]: A note on the measurement results may be found at
    http://www-physics.lbl.gov/\~jtaylor/REPORT_comb.doc.