NEWS  -  cern.ch/dem/news

Quote:

"Innovation in the realm of electronic interconnects is alive and well in Europe.
Perhaps it's nowhere more the case than it's at CERN"

The online magazine for the PCB industry PCB007 also reported about Joe's visit in "Fjelstad Visits CERN Accelerator Complex".

28 October 2008.

As the lead-free solder has a much higher melting temperature than leaded solder (217 °C vs. 179 °C), the risk of damaging the components and PCB is increased. The temperature control of the soldering iron has therefore become much more important than before and is the reason why we also have standardised precise soldering irons with dedicated tips for touch-up and repair work.

If you like to get more information of the standardised solders, flux, desoldering wick and soldering irons or like to try them out please contact Sylvain Kaufmann. 

Inspecting components embedded in a PCB

27 October 2008.

The exchange of ideas about production techniques may help us both to advance into the future. Joe also gave a lecture in which he presented many practical things such as how the layout of flex circuits can make them more reliable. Furthermore he presented his visions on embedded logic and splitting high-speed chip-to-chip communications from the other connections. The latter ideas are still rather far off from being reality, but they may indeed show future directions and hearing them was rather stimulating.

If you're interested in his ideas, the free book Flexible Circuit Technology is a good starting point.

16-layer board connects all 10 detector layers

Veritable marvels of technology, these cylindrical vessels can be moved to within one millimetre of the beam centre. They contain detectors that will measure very forward protons, only a few microradians away from the beams, that arise from elastic scattering and diffractive processes.

On the accompanying image you can see the stack of ten different flex-rigid circuit boards with an integrated special layer of material that removes the heat from the silicon detectors. The density of lines, the planarity and the overall dimensions are important features of it. The Motherboard that connects all these detector boards has 16 layers (pdf 3MB).

The layout and production of the boards and the assembly of the components have all been done by TS-DEM's services.

Neutron detector company based on
 GEM technology invented at CERN

As CDT now is ready to sell its detectors, it requested CERN a licence to use the patented technology in a commercial application. CERN has awarded this request. Commercial details have not been disclosed.

For more information and technical details see the website of CASCADE Detector Technologies.

There are numerous applications of MPGDs. In R&D studies, thick GEMs are used for the detection of single photons in Cherenkov imaging counters. At Jefferson Lab, a new multipurpose spectrometer is being developed, where GEMs could be used in particle tracking at high rates. GEMs are also being developed for digital hadron calorimetry in experiments proposed for the International Linear Collider (ILC) – a very high granularity can be achieved with small cells that are either "on" or "off". Groups working on experiments for the ILC have in addition designed large TPCs with MPGD read-out, and both GEMs and MicroMegas are being considered for this role. In other developments, MicroMegas detectors read out the TPC for the Tokai-to-Kamioka experiment in Japan, or can be used as muon detectors at high counting rates, such as in the upgrade of the ATLAS detector at CERN for the SLHC.

As maker of high-quality GEMs and MicroMegas TS-DEM is convener of the RD51 working group on "Development of cost-effective technologies and industrialisation". This working group aims to develop a common production facility, to optimise production industrialization (quality control, cost-effective production, large-volume production) and to guide collaborations with industrial partners. You may contact Erik van der Bij if you are interested in this working group.

Flexible Kapton cables connecting the ALICE SPD circuits made by TS-DEM

Material budget considerations also led to the development of the pixel bus, a high-density aluminium/polyimide multi-layer flex. This technology, in which aluminium is used in place of copper, is not an industry standard and was made possible by the expertise available in the TS-DEM workshop at CERN.

The material budget of this pixel detector is so important as it is the first detector that the particles cross after collision. You may appreciate the technological complexity of this project by viewing The development of the fabrication process of "low mass" circuits presentation of Rui de Oliveira.

The assembly workshop TS-DEM soldered all components on the modules used in the 120 half staves, while the PH Bonding lab has made the die attachments.

The CERN Courier wrote also on a previous occasion about TS-DEM: "Spark-proof GEM gives higher gain".

COMPASS MSADC

Do not start new designs in PCAD: use Altium or Cadence

PCAD library support stops end 2008

Altium Designer can import PCAD designs and it is available for installation from CMF. Special migration courses for PCAD users as well as courses for schematics entry and PCB design with Altium Designer are organized by technical training, there are upcoming sessions in September and October.

TS-DEM will support Altium as it did PCAD, i.e. manage the libraries and route printed circuit boards. TS-DEM can also migrate existing PCAD designs to Altium.

4 July 2008.

It is not mentioned that it is TS-DEM who has produced these monitors for the team of Thijs Wijnands and Christian Pignard. In fact since 2005 DEM has been tightly involved in the development of these RADMONs (or EDA-01793 in our terms). We designed and built the various PCBs (main card, power card, sensor cards), the compact metal box around it and various adapters that allow the radiation monitor to be fixed to various structures in LHC.

26 Mai 2008.

DEM bases its quality control largely on IPC standards that are recognised world wide. One of the norms is IPC 7711/7721: "Rework, Modification & Repair of Electronic Assemblies" of which a new version is just released.

Other important IPC standards we use are IPC-A-600-G: "Acceptability of Printed Boards" and IPC-A-610-D: "Acceptability of Electronic Assemblies".

DEM also uses these standards in the technical specifications and when qualifying its PCB producers and assembly companies. Selecting the right IPC norms is not always an easy task as there is a complete IPC specification tree and sometimes they need to be tailored to CERN's specific needs.

"The gas detectors for the TOTEM experiment (GEM) offer potential for fruitful collaboration within the framework of the TT network. Many other technologies are going down the same road."

Renovation should provide a 60% reduction in faults

5 March 2008.

TS-DEM showed their assembly facilities to members of the FGC3 design team during which Quentin King, section leader of AB-PO-CC made a nice series of photos that show the assembly process. The complete slideshow shows even more details with comments.

Scoop!

The secret picture of
the top of the DEM organisation

At the forefront of the development of electronic modules, the DEM group provides continuous support for the engineers and technicians of the LHC experiments.

"Electronics at CERN are in a way CERN’s nervous system. Electronic components form an integral part of the data transfer and detector control systems", says group leader Erik van der Bij. "Our objective is to be able to provide the expertise that is not available in industry." 

The DEM group produced 400 electronic circuit boards needed for controlling the LHC accelerating cavities at Point 4.

Press-fit connectors may be replaced up to 5 times without any risk

30 January 2008.

The second machine is a small pneumatic cutter aka off-cut remover that is used to remove printed circuit boards from the panel in which it is produced. It cuts precisely the tabs that hold the PCB in its production panel. A standard cutting tool may delaminate a board or may even put so much stress on it that (ceramic) components near the cut will crack. The picture above shows the difference in result between a standard cutter and the new pneumatic one that is affectively called Hektor. You may contact Sylvain Kaufmann for more information about these tools.

In 2005 he reinforced DEM's design office section to set up a professional subcontracting service with the additional service of purchasing electronics components. After 38 years of CERN he now retires and will stay active with his car hobby. We very much appreciated all his work and presence and wish him and his family a long and healthy life!

Claude Millerin (center) with a few of his dear colleagues

25 January 2008.

"Sylvain Kaufmann, production technician at CERN/European laboratory for particle physics, talks about the need for accuracy — it has increased with the growth of component size and sensitivity variety. Flexibility became a major factor."

"Temperature and ΔT during process steps (preheat, soak, peak, etc.) and repeatability from week to week are important to Kaufmann at CERN. He measures these using generic boards pre-wired with thermocouples connected to a thermal profiler."

TS-DEM participated in
production problem solving

200 μm sized Via hole showing crack

The article does not tell that Rui de Oliveira, section leader of DEM's PCB workshop, had helped to solve severe production problems of these hybrid circuits. On Rui's suggestion the stack-up of the different layers inside the circuit was modified to prevent via holes to crack and generate bad connections. Furthermore he interacted with the production company which resulted in a document that improved the quality assurance for the production of these hybrids.

TS-DEM is happy to have participated in making this project a success. This example confirms the statement of the CMS spokesman Jim Virdee: "Building a scientific instrument of this size and complexity is a huge technical and scientific achievement".

Every year DEM gives practical training to apprentices

21 January 2008.

What is not written is that Stéphane has learnt the art of electronics production in the electronics design office and the SMD assembly workshop of TS-DEM. He spent 6 months with us during which he also learnt how to produce printed circuit boards. In fact every year DEM trains up to two apprentices in collaboration with Jean-Marc Bouché, head of CERN’s apprentice training programme. We're very happy that Stéphane has won this price that will most certainly help him in finding an exciting first job!

A series of these so-called GDAC GFAC boards, that control most of the power converters of the PS complex, needs to be fabricated again as the Controls group in the AB department is running low on stock. To be able to survive until a new system is designed TS-DEM will produce 50 spare cards.