## [Phase II of the cooling project.]{.underline}

**Phase II-1 : End of July (pursued in the cooling group).**

Post review studies :

-   Further analysis of existing data

-   Re-measure existing structures (key-measurements) with mixtures and
    full power - change compressor (ATLAS COPCO)

-   Further studies of thermodynamic parameters of mixtures.

-   Design and make input/output heat-exchanger and regulator scheme in
    single stave setup (to be modified)

-   Optimization of dimensions and specifications for SCT and PIXELs.
    Design criteria for structures. Thermal gradients.

-   Cable cooling layout (Services WG)

-   First layout in the crack region, material-distributions and
    estimates (Services WG)

-   Costing of phase II and final system.

-   Define new thermal test-structures for detailed measurements and
    system measurements to be developed by the SCT and PIXELs.
    Work-packages.

-   Special meeting needed in July to conclude this ?

-   Implication of TRT ASIC power increase.

**Phase II-2 : End of 1999**

**Item 1 :** Develop and conclude TRT electronics layout cooling for
increased power by September.

**Item 2 :** Construct structures for the detailed cooling engineering
test and the system tests, including heat-exchangers. Discussion and
definitions in the SCT/PIXEL communities.

Timescale for these structures September (structures for detailed
studies) to December 1999 (for system structures).

**Item 3 :** Detailed measurements of simple structures for
optimization, heat-exchangers, performance, engineering and structure
parameters. Can partly be performed using the existing cooling
facilities at CERN and similar facilities in other institutes. Results
by November 1999 (linked to SCT structure PRR).

**Item 4 :** Detailed studies of thermal contacts to the modules and
thermal performance of the modules. This is mostly an engineering study
but it will connect to and should use the cooling plant for parts of the
studies (single tube setup). Responsibility of the SCT and PIXEL
engineering groups.

Results by November 1999 (linked to SCT structure PRR).

**Item 5 :** Design of TRT and SCT/PIXEL cable cooling plant (monophase
+16) by October.

**Phase II-3 : Time-scale middle/end of 2000.**

**System performance.**

Work out detailed specifications and costing.

Prepare larger system (5-10kW) for system aspect studies, by the end of
the year.

A system for mixtures or C3F8 has been shown by M.Bosteels
(transparencies) with individual control of the cooling circuits. Such a
system can be developed before January 2000.

A thermal shield prototype is needed.

A request for space in bat. 186 with the correct height differences,
infrastructure and dimensions has been submitted.

Systematic measurements using this cooling plant to cool structures
start at CERN in January 2000.

To address : system performance and control, stability, faults,
start/stop, operational issues, structure performance, etc.

**General on-going activities throughout the whole period:**

**Item 1 :** Irradiation of all components in the cooling systems.

Responsibility of the LHC cooling coordinator (A.Smith).

**Item 2 :** Material compatibility studies of everything which can come
in contact with the liquids.

ID and SCT, PIXEL engineering responsibility.

**Item 3 :**

-   Development of a DCS system based on Bridgeview and CAN for
    measurements and monitoring of the thermal structures

-   Interlock systems

-   Analog control of Fluid Mass Flow and Boiling Pressure.

Responsibility of ID cooling group and DCS groups.