Tracker Status

October 29, 2004

 

Ladder Assembly

-        About 1300 ladders with good IV curves are complete (about 9 towers)

-        248 more are ready for electrical testing

-        260 are in fabrication

 

Bias Circuits: 571 out of 850 delivered by Parlex.

 

Tray Assembly

-        Plyform is continuing with fabrication of tray panels.About 90 bare tray panels have been fabricated to date (over 25% of the total).21 finished trays have been delivered (not counting the test articles), and 20 passed the thermal-vacuum test (one failed with complete debonding of the primer from two thin tungsten tiles).

-        GSFC is processing tungsten tiles through etching and priming.

-        G&A finalized the new MCM bonding procedures (revised to ensure connector clearance) and completed two flight trays.

-        One tray with MCMs bonded (but no SSDs yet) has a problem with no bias from the MCM to the two center ladder attachment points on the bias circuit.The cause is not yet known, but a new procedure is being introduced at SLAC to probe test delivery of bias voltage to all bias wire-bonding pads on the pitch adapter before shipping to Italy (the normal automated test sequences donít verify this until detectors are attached).

 

Sidewalls

-        The Tower-A sidewalls are complete and in Pisa.

-        A second set of sidewalls is nearing completion.

-        All of the flight-build prepreg is made, and we are working on getting it to Italy and through customs.

 

MCMs

-        Work is in progress at SLAC to clean conformal coating off of connectors on MCMs to be delivered end of next week for Tower B.

-        Work is still in progress to get Teledyne back on line with the MCM production.

-        Visual inspection and manual probing of pitch adapters is continuing while work proceeds in implementing the more automated electrical test into the production.About 14% of MCMs are being lost to cracked traces, which is too many.Parlex is late in delivering all the new-design pitch adapters that we need to test, hopefully avoiding trace cracking.

-        DDI presented (likely) cause and corrective action for the short circuits observed in several MCMs from one lot of prepreg material.

 

Flex Circuit Cables

-        Work proceeds on getting prototype cables from two new vendors, one of the two cases being long cables spliced from pairs of shorter cables.

-        Serious workmanship and QA problems have now been found with Parlex cable assembly (gluing and soldering connectors, etc) and a stop work has been put on the assembly operation.This is a serious problem for Tower-A: we do not have a set of flight-worthy cables.

 

Tower Assembly,

-        The work shutdown at SLAC halted work on a number of GSE items needed for tower assembly and shipping.That work has been moved off-site now, and it appears that we will have everything just in time.