LIU ion meeting 13.2.2014
10Hz injection rate in LEIR – necessary upgrades and
precautions
Attendees:
M. Bodendorfer BE-ABP (Secretary)
J. Cravero TE-EPC
A. Deleu BE-ASR
S. Deleval EN-CV-OP
E.B. Holzer BE-BI (Deputy chair)
D. Kuchler BE-ABP
D. Manglunki BE-OP (Chair)
Excused:
D. Bodart (TE-MSC-MNC)
Summary of action items (in order of occurrence):
 D. Manglunki specifies an increased thermal dissipation for the LIU upgrade
10 Hz operation in the LINAC3 hall and forwards it to S. Deleval.
 S. Deleval investigates the cost and the schedule for providing cooling for the
increased thermal, specified by D. Manglunki. He also finds out the cost and
the schedule for the repair of the roof of the LINAC3 hall.
 D. Kuchler produces an ordered list of items to purchase and work to be
carried out for a given LIU ion source update budget of 5 Million Swiss Francs
and forwards it to D. Manglunki.
Discussion:
 Bending magnet replacement
J. Cravero asks for a clear statement about whether the magnets between
LINAC3 and LEIR need replacing. D. Manglunki forwards the question to D.
Bodard (absent).
 Project approval
J. Cravero forwards the question of his group leader Jean-Paul Burnet (TE-EPC)
whether the LIU IONs project is approved. D. Manglunki confirms that the project
is approved. He explains that LHC should produce until 2030s 10 times more
inverse nanobarns compared to p-Pb run in 2013. This results in 10 inverse
nanobarns of integrated luminosity for lead ions. He states that this level of
increase is not feasible within the next three years. He adds that this is the
motivation to increase the repetition rate of LINAC3 to LEIR from 5Hz to 10Hz.
 Air conditioning and magnet cooling
D. Manglunki states the challenge of an estimated increase in thermal dissipation
of 50% for the increase in repetition rate from 5Hz to 10Hz. S. Deleval replies
that in the past there have been significant problems with the plumbing of the
chilled water system, which is used to evacuate heat from the water-air heat
exchanger of the LINAC3 hall air conditioning unit. He identifies that the waterair heat exchanger has represented a limit of heat evacuation from the LINAC3
hall in the past. S. Deleval explained that during the LS1 valves have been
installed and should allow to balance the PS complex chilled water circuit and fix
the lack of chilled water. This would allow evacuating the nominal heat load of
the ventilation system. D. Kuchler stresses the deprecate state of said water-toair heat exchanger units. S. Deleval adds that the existing air conditioning unit is
partly comprised of Asbestos.
D. Manglunki asks about the option of using a separate, detached cooling unit in
order to leave the existing air conditioning unit in place. S. Deleval answers that
during LS1 it has been used but it required room in the Linac hall and it’s for
limited heat load.
E.B. Holzer asks whether an increase in the flow rate of chilled water would help
mitigate the challenge imposed by the increase in thermal dissipation caused by
the 5Hz to 10Hz upgrade. D. Kuchler believes that the air heating effect of the
magnet coils would not be reduced enough by this measure.
D. Kuchler explains that the thermal expansion of an LINAC3 RF cavity limits the
operating temperature of the surrounding air to 27 to 28 degrees Celsius. Than
the RF tuners reach the end stop and the cavities cannot be tuned any longer.
S. Deleval suggests avoiding the hottest period of the year for operation and,
hence, not challenging the thermal evacuation limit of the air conditioning. D.
Manglunki replies that the schedule foresees LINAC3 operation during summer
2014.
S. Deleval asks whether for LIU the de-humidifiction function of the existing unit
is really necessary because it could be a mean to get some additional cooling. D.
Kuchler confirms that such a humidifier is necessary to avoid water
condensation on electrical machine parts.
J. Cravero asks whether replacing the DC magnets in LINAC3 with pulsed
magnets, which dissipate less thermal power, would be more cost effective than
a new air conditioning. D. Kuchler denies this. He explains that the four bending
magnets of the ITF-chicane consume a combined electrical power of 600kW. He
suspects that replacing these magnets and their power converters would cost
more than an upgrade of the air conditioning.
Post meeting communication with J. Cravero:
The total output power for the converters of the bending magnets is:
 ITL.BHZ01, ITL.BHZ02 ~10kW (5kW each)
 ITF.BHZ11, 12, 13 and 14 ~ 100kW (25kW each)
J. Cravero adds, if it is feasible to replace the ITF converters and magnets, that
are DC powered, by pulsed ones, it will reduce the requirements for a new or
refurbished cooling system. Furthermore, if pulsed magnets are preferred,
this option will reduce electrical power consumption of both converters and
cooling system for years.
In order not to increase the dissipated power in the LINAC3 building for the
10Hz operation upgrade, J. Cravers suggests to specify the coils of new
quadrupole magnets with an Ohmic resistance low enough so that the dissipated
power after the 10hz operation upgrade will not be higher than the one of the
existing setup.
S. Deleval suggests increasing the flow rate of the chilled water from Linac2 to
Linac3 in order to provide a higher heat evacuation capacity of the cooling
system. However, currently the ventilation system (water-to-air heat exchanger)
is the bottleneck and needs replacing due to its deprecate state. E.B. Holzer asks
whether the concept of recuperating additional cooling water from other
facilities could be tested during the 3.5 months tech-stop in winter 2016/2017. S.
Deleval replies that this tech-stop is not long enough to update the air
conditioning, nor long enough to repair the roof.
 Civil engineering challenges with the roof of the LINAC3 hall
D. Kuchler states that the roof of the LINAC3 hall needs repairing. S. Deleval adds
that the LINAC3 roof is comprised of Asbestos and any repair or removal would
require significant time due to the safety measures for Asbestos removal.
D. Manglunki closes the meeting at 17h.
Next meeting: February 27th, 2014