NEWS 2007

Take part in the production of electronics for the world's most famous particle physics laboratory!

Important function to consolidate the quality both within the group and with CERN's subcontractors

TS-DEM-2007-114-LD

Keywords: assembly, electronics, SMD, quality, production, design rules, job offer, PCB,

Mots clés: assemblage, électronique, CMS, qualité, production, règle de design, ouverture de poste, circuits imprimées
TS-DEM-2007-114-LD
(en français)

Technical Engineer (Electronics)

As assistant to the manager of the design and subcontracting office, you will:

• maintain up-to-date design rules for manufacturing and assembly
• provide technical support to the design office and its customers in terms of manufacturing and assembly process
• verify that jobs created by the design office comply with the defined design rules
• provide technical support to the industrial support team for component purchasing
• participate in selection and audit of subcontracting companies in the member states
• contribute to the definition of the technical specifications for PCB manufacturing and assembly
• with the assistance of the industrial support team, organize and follow-up the manufacturing and assembly of the jobs designed in the group
• define and maintain the related quality procedures and documents

Qualification required

Technical Engineer diploma or equivalent in electronics.

Experience and knowledge

• Up to 8 years' experience in design and/or production of electronic circuits and systems
• Very good knowledge of electronic module design, front panels and crates as well as manufacturing rules and industrial standards
• Experience in quality assurance in a similar technical environment
• Demonstrated ability to work as member of a team
• Familiarity with CAD software for electronics design
• Good understanding of English or French, basic knowledge of the other language or an undertaking to acquire it rapidly. Knowledge of other European languages would be an advantage.

Information on how to apply are available from CERN's e-recruitment system, vacancy notice TS-DEM-2007-114-LD

For any questions about this job offer in a group that has a working method similar to industry, don't hesitate (really!) to ask for more information from Erik.van.der.Bij@cern.ch

Version francais de la description de poste:  TS-DEM-2007-114-LD
N'hesitez pas de demandez vos questions concernant ce poste au Erik.van.der.Bij@cern.ch

Rightmost image shows the LHCb VELO silicon detector circuit developed and fabricated by DEM

Logo leaves place for tracability information of PCB manufacturers

Three thousand floppy disks copied with only seventeen failed.

In fact it was very hard to find a working 5¼ inch drive, but it was the IT support who found one and configured a PC for us that could read both sizes of floppies. With a clever utility written by William Billereau and only two weeks of work by an enfant de fonctionnaire we have copied well over 3000 floppy disks containing over 25000 files. Out of those 3000 disks just 17 failed to read; not a bad result for disks of almost 20 years old! At the time the CERN Stores must have done a good job of standardising on high quality disks.

It still happens several times a year that engineers ask us to find back old designs or to even reproduce them. Since 2003 we store systematically all design files (schematics, PCB production and assembly) in the EDMS system with the well known item number EDA-xxxxx. Designs made before 2003 are stored on the DEM dfs network disk area.

So far and in the near future, halogen-free PCBs are not yet legally required by the European Commission RoHS regulation...

... but they are by CERN!
(and for good reasons)

TS-DEM produces (and orders) boards that are halogen-free and RoHS compatible

17 October 2007. We recently received the question if standard FR-4 materials are not authorised in the CERN caverns as they are not halogen-free. The answer is clear:

It is true that CERN's safety commission has banned halogens in materials. Please see the following notes:

• Safety considerations for the purchase of Printed Circuit Boards - Memo - Presentation
• Safety Instruction IS 41: The use of plastic and other non-metallic materials at CERN with respect to fire safety and radiation resistance - English - French

For practical reasons, mainly the difficult availability, most boards ordered for CERN were ordered without any specific requirements until around the year 2006. However, since the last two years it is perfectly possible to order halogen-free PCBs from many (but not all) manufacturers and there is no valid reason to order boards that contain halogens. In several recent conferences we see that halogen-free is becoming more common, but most orders placed with companies still do not specify halogen-free.

Note that in most cases you also should specify that the boards should be RoHS compatible, i.e. that they do not contain certain toxic materials and, also very important, can withstand the higher solder temperatures that are needed when soldering with lead-free solders. So specify "halogen-free and RoHS compatible". Of course to obtain a certain quality level, there are many other parameters to specify when ordering a PCB.

As far as CERN's support group for the fabrication of electronics is concerned (TS-DEM), all the boards that we produce at CERN and those that we order from external companies are halogen-free and RoHS compatible.

The IPC A-610 industry norm defines 'good' assemblies and is based on the experience and research of a large number of companies

The IPC association provides detailed norms that are well known by the electronics industry. For that reason the DEM group has become member of the IPC association and uses the IPC norms for layout rules and assembly quality control. Members of the personnel in the workshop also have been to dedicated courses such as "Acceptability of electronics assemblies", based on the IPC A-610 norm.

IPC also has norms for PCB fabrication such as IPC A-600: "Acceptability of Printed Boards" that is used by the PMT workshop as its main reference.

Please contact Betty Magnin if you are interested in consulting or buying IPC norms.

Designs that take less than two days work will be handled immediately

26 June 2007.

We can do this fast service for two designs per week without disturbing the planning of other jobs. In addition, to speed up your project even more we can also produce your boards fast (e.g. a single day for a 2-layer board, three days for a 4-layer board) and we can assemble your board in our workshops. See also our list of PCB fabrication times.

Melting temperature of new solder is over 30 degrees higher; not all components resist to this

CERN's assembly workshop uses lead-free solder

PCB workshop produces boards that resist higher solder temperature cycles while being halogen-free

To help CERN's engineers and technicians become aware of all the different aspects of the RoHS directive, DEM has organised a half-day course (slides) with a program adapted to CERN's needs.

TS-DEM itself has made the change to RoHS over a year ago: all assembly personnel has followed dedicated training from a specialised institute in Paris and use lead-free solder processes whenever possible. Our PCB fabrication workshop has switched over to new (high Tg) base materials that allow the higher soldering temperatures, while we made at the same time the change to halogen-free materials as required by CERN's safety instruction 41.

15 June 2007. As part of its continuing education, the TS-DEM group has visited a high-tech Swiss PCB manufacturing company. This visit was not only useful for the people making boards at CERN, but also for the people from the design office and the assembly workshop. With small groups being guided by technical staff from the company, the tour was excellent and stimulating.

In a way seeing all the relatively new machines and the nice environment made us feel jealous. On the other hand it made us proud to see that with our limited resources we at CERN can build a larger variety of circuits than a company that is optimised for production can ever make.

As the (bus-)trip took over three hours, we have combined the visit with our yearly 'picknick'. As it was raining hard we were very happy that the company offered their space to use our lunch. As thanks DEM had offered a DVD from the CMS experiment (for which they produced numerous circuits) and some sets of CERN playing cards.

Neutron detector company based on
 GEM technology invented at CERN

Dr. Klein (l), founder of CDT, showing his neutron detector to DEM staff

The company CDT makes GEM-based neutron detectors developed with the CASCADE detector project. One detector of this type may contain up to ten GEM foils resulting in an extremely high sensitivity. The speciality of the company is to make fully working turn-key systems that include the readout electronics and software. Another core value of the company is its technology to add precise Boron conversion layers to GEM foils. Boron converts the 'invisible' neutrons to photons that can be detected with the mature GEM technology. The company was founded after positive feedback and serious interest both from Japanese companies and European institutes.

For more information and technical details look at CASCADE Detector Technologies' website.

DEM presented GEM detectors and
Micro-Chemical-Vias technology
at Salon des Inventions

One hair would just go through this MCV hole!

CERN's research and development strategy includes a programme where technologies developed at and for the Laboratory are jointly developed with industries, so that they may be adapted into a commercial product for other uses. These include many different domains of applications such as medical imaging and IT.

The company TTA Techtra was awarded a silver medal for the Micro-Chemical-Vias (MCV) prototypes designed and built in collaboration with CERN. The MCV process allows the company to produce printed circuit boards using chemical etching on a production line, resulting in reduced costs and a much shorter production time. This patented process technology has been invented in DEM's PCB workshop. See also CERN Bulletin Issue No.22/2007

23 May 2007.

Another member of DEM ran in the open ladies category and with 14:58 Les Gazelles occupied even the second place in their category!

All official pictures and even movies from this yearly CERN event can be found at the website of the CERN running club.

Also for your projects DEM can make stickers and other posting signs on various supports (metal, plastic, etc.). DEM's productions  can already be found on several accelerator components and on the CMS detector.

2 May 2007. As CMS has made much use of the expertise and production capacity of the TS-DEM group, the whole group was offered a visit to the CMS construction site. It was very impressive to see the huge detector and to spot the deeply hidden places where the electronics is installed.

The trip down 100 meter under the ground made us well aware of our responsibilities in this large enterprise. Of course it was also quite a lot of fun for us to see again the circuits that had passed through our hands in the past few years. This ranged from tiny hybrid circuits, crate controllers with fire detectors and data links to the gold-plated panels showing the names of all CMS collaboration team members.

Three double sided boards built and delivered on the same day!

2 March 2007.

As a trial DEM will therefore now, in collaboration with the Finance department, offer this full component purchasing service. Please contact Erik van der Bij for more details.

Abrupt phase change of the cavity RF used to maintain longitudinal stability

1 March 2007. CERN's Proton Synchroton accelerator has a hardware system to measure the trajectory of the particles. As it was designed for protons, it had some difficulties handling the ions that are nowadays accelerated. Therefore one had to look again at the old hardware designs that were made over ten years ago.

The engineer who designed this electronics had left the group a long time ago and it was not fully clear where all design documentation was. Therefore the current engineer asked DEM to find back the schematics and PCB layout files of the design. With the help of the reference number printed on the PCB, DEM's design office could easily find back the schematics that were stored on its dfs file system.  The hardest part was to be able to read the files that were made with the obsolete PCAD sofware version 5. In fact DEM keeps two old stand-alone machines running with Windows 95 and several versions of PCAD to be able to read old files. Since 2002 DEM stores not only the CAE design files in the EDMS system, but also a pdf file of the schematics and of the PCB layout in order to always have human readable documentation available.  It happens several times per year that DEM is asked to recover old design files.

6 February  2007. The Open Day of the TS Electronics assembly workshop had attracted well over eighty people. The feedback was very positive: in general people were impressed by the changes done in 2006, notably of the purchase of new machines and the refreshing of the assembly labs in general. The subjects that attracted most interest were the BGA rework station including the method of reballing used BGAs, the solder paste screen printer and the PCB cleaning machine. Also the new RoHS (lead-free) norms and implications for assembly were discussed.

Tunnel work for DEM?