status of bpix cooling activities

March 19, 2013 W. Bertl, PSI

Status of BPIX Cooling Activities

W. Bertl, PSI


Where we stand now

Bpix cooling pipes layout has been designed based on

- expected power load beyond LS2 with up to 500 fb^1 int.luminosity (using measured data of present Bpix and extrapolated for upgraded Bpix)

- thermodynamics of 2-phase CO2 (typ. @ -20 / +15 ºC using Thome correlations)

- measured thermal conduction between coolant and sensor using a test setup (again scaled to upgraded system)

- reasonable coolant flow rates and acceptable pressure drops

Detailed technical drawings on Bpix piping exist (S.Streuli)


Still to be done

- Verification of power load for new ROC chips under extreme beam conditions (including a realistic supply tube layout only small corrections expected)

- Experimental verification of thermodynamic calculations with a 1:1 mock-up (using one of the final cooling plants)

- Extending the experimental tests for asymmetric, accidental load conditions (like a sudden power failure on modules of one of the parallel cooling loops)

- Determination of the dimensions of the capillary pipes preceding each parallel cooling loop

- Testing the cooling down procedure under realistic conditions

- Designing and testing of an emergency power break in case of cooling loss


Current activity

Construction of the 1:1 piping mock-up for half of Bpix.

Technical drawings made by Silvan Streuli based on design considerations

Construction at the University Zurich (P. Robmann and workshops) with 3D pipe bending outsourced to a Swiss company.

Two systems will be built. One system for the +x shell, one for the –x shell seen from one z-side. (+x/-x loops are based on a very symmetric layout (based on power load) and will share main supply loops. Cooling behavior in case of cooling losses at one side can be studied. Between +z and –z there is a strong symmetry and the cooling loops are decoupled.)


One of the two systems under construction

Support disks to hold pipes in place - for suppy tube - for Bpix detector

Some pipes already placed into position


Bpix “flange”


Supply Tube Connections


Two loops on Supply Tube


Conclusion

Mock-up construction:

After difficulties at the beginning (wrong steel type, problems with small bending radii) the progress of the pipe bending company is good now. Most parts for one system are delivered. Small connection pieces and fittings are available.

Completion of both piping systems (including leak testing) is expected for end of April.

Then heating clamps and temperature sensors can be mounted (by R. Becker).

Finally, the systems should be ready for operation tests using the Cern cooling plant.

status of bpix cooling activities

Documents