This initial meeting was primarily intended to explain the reasons
for setting up the CWG, introduce those attending and establish a method
of operation for it.
The CWG is designed to bring together those involved in electronics
cooling in the LHC physics detectors so as to establish a common approach
to the technological systems used and with the aim of acquiring cooling
systems with acceptable quality and cost criteria.
Detailed Minutes:
1- Introduction:
For this initial meeting, which established the CWG, Bosteels made
a rapid overview of the electronics associated with physics detectors.
Because of the density of electronics components, and their power, the
use of a liquid heat transfer medium (either two-phase or otherwise) is
required, both inside the detectors and outside in the counting rooms.
The exchangers for removing the heat must be in close contact with these
components. For example, ATLAS has calculated the power needed to extract
the heat from the whole of the experiment as being some 10 MW.
This overview was followed by short presentations by each participant.
2- Objectives:
The CWG activity will cover the cooling of electronics for the LHC
physics detectors. Financial and human resources of CERN and Collaborations
are no longer large enough to multiply studies, tests and technologies.
The CWG is intended to bring together the technical staff of CERN and
members of different collaborations involved in cooling so that they can
all pool their individual experience and benefit from that of others.
More precisely, the aims are to:
-Make an inventory of the different detector dissipators and collect
specifications (power, temperature, gradient) relating to them (a few hundred
Watts overlooked can have a disastrous effect on temperature control).
- Draw up a list of the different technologies that may be envisaged
for cooling systems, together with the fluids and control systems used.
-Identify common items to manage minimum standardization.
-Draw up technical specifications for the various common elements with
a view to approaching industry (or institutes) and providing collaborations
with lists of products at the lowest possible prices.
Initially, the CWG is not intending to enter into the design of exchangers
in the detectors, which is the task of the various collaborations, but
some of the participants stressed that the latter was the most urgent task
at present. The CWG was clearly ready to open any discussion which would
provide technical solutions to collaborations that so desired.
The monitoring and maintenance of cooling systems (some of them relatively
complex) during the years of LHC operation was also raised as a question.
3- Composition:
Those present included representatives of Alice, Atlas and CMS working
at the infrastructure integration level, the ECP pool that provides electronics
equipment (racks, crates, power supplies, etc…) to collaborations, the
PPE/TA1 group lending technical assistance to the experiments, and the
EST/SM/SF section which specializes in such cooling.
Bosteels recalled that the working group was open to all those involved
in cooling systems for the electronics, and encouraged representatives
of the experiments to pass on the information to their own communities
and collect from the latter matters at issue in this domain.
It was hoped that a member of TIS would take part in the CWG, so that
the technological options, in particular for fluids, would take safety
considerations into account.
4- Organisation and communication:
Bosteels would act as Chairman of the meetings and coordinate the CWG's
work. Bonneau would produce the minutes. Meetings would be held on the
first and third Wednesdays of each month from 10 a.m. to 12 noon, to be
confirmed by e-mail.
Minutes would at first be circulated by e-mail, the aim being subsequently
to set up a Web server for the minutes, the equipment catalogue, and a
newsgroup.
5- Resources:
The CWG does not have any resources of its own apart from those of
its participants. The PPE/TA1 group can provide secretarial support.
6- AOB:
Hatch presented Atlas's overall coolant circuit diagram and pointed
out that the Atlas Technical Coordination Group (i.e. ST/CV) was responsible
for it up to and including the primary exchangers (cold side). Secondary
circuits (from the underground hall to the electronics) were the entire
responsibility of each of the collaborations responsible for their own
detectors. It was up to them to call in outside assistance.
Gregory thought that the Alice Infrastructure Group would support the
cooling support systems as far the point of entry into the detectors.
Many were interested in the binary ice system and a presentation by
the Atlas Rutherford Group as part of their TDR was planned for the near
future.
The next meeting would be held on 5/02/97, Room 40 RA10 from 10 a.m.
to 12 noon.
Agenda:
1-Approval of the previous set of minutes.
2-Overview of cooling systems and usable fluids.
3-Evaluation of the needs of collaborations for cooling prototypes
and for tests.
4-The different measurement systems, (temperatures, pressures, flow-rates,
etc. )
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