Presents: RWA, CB, HB, SF, MG, JJ, JBJ, AK,
RdM, GRdM, SR, FS, TW
- Follow-up of actions from previous meetings
- Correction of aperture database (Action: MG).
- Even though the
aperture database is not completely up-to-date and fully cross-checked, S.
Chemli said that the part concerning the octant 8 should be almost correct. It
is then decided to make an attempt of extracting the data from the database,
generating the aperture model and comparing it with the one developed by SR
(Action: JJ).
- Verification of
the aperture in IR8 (Action: WH, JBJ).
- The action is still in progress. A value of
the crossing angle for beta*=1 m has to be defined so that the available
aperture is conform to specification for both polarities of the spectrometre's
compensation magnets. This issue is crucial for the acceptance of the triplet quadrupoles of IP8, which is on-going at MEB.
- Additional check of the electrical drawings for point 8
(Action: MG).
- The five drawings for IP8 were checked by
JBJ, FS and MG. Few errors were found and they were communicated to P.
Proudlock.
- It was found that the MQTLs in Q11 are
reported to be rotated by 180 degrees with respect to the vertical axis in the
layout database (hence
with connections downstream of the beam direction), while this feature was not
reported in the electrical drawings. Following a number of checks with the
experts (H. Prin, S. Russenschuck et al.) it was found that: the layout
database, which was reporting the rotation, is indeed correct (this is crucial
as the new version of the error routines is based on the information extracted
from the layout database). However, as far as the polarity is concerned,
inside the assembly the appropriate modifications are made so that from the
outside the cabling is done as if the MQTLs were not turned.
- Report from meetings
- MEB -> SF
- Approval of SSS is
in progress: sectors under considerations are 4-5 and 7-8.
- Approval of MB is
in progress: sectors 7-8 and 8-1 are completely allocated; sector 4-5
features about 30 missing MBs; sector 3-4 features about 120 missing MBs.
- FQWG -> SF
- The difference in
magnetic behaviour of main dipoles according to the type of inner cable
(i.e. type 01E or 01B) is almost negligible. The largest difference is found
for the hysteresis of b1, for which 3 units were found. Therefore, it is
decided to allow for mixing a limited number of cryodipoles with different inner
cable in the same sector.
- The results of the
measurements of the field direction in SSS gave a value of 0.8 mrad (rms):
the limit is 0.5 mrad (rms). The situation is considered to be
conform.
- LTC -> MG
- A discussion on the organisation of the
LHC commissioning took place:
- Responsibility of the commissioning will
be of the EIC.
- Experienced EICs will need to have
experience of operation of collider machines.
- The newly recruited EICs will not be
responsible for the LHC commissioning, but they double the experienced ones
and will be in charge of the machine after the commissioning.
- In a future meeting the planning of
installation of LSS8 will be presented. The DFBX will be missing, hence no
power tests will be possible for the low-beta triplets. Implications of this
fact on the sector test should be made by LOC: feedback is required before
the LTC meeting in three weeks.
- CWG -> RA
- Analysis of the resistance test (flatness
of collimators) completed. Software upgraded to take into account any
deformation of the jaw surface (e.g., fit of measured shape, parabolic
deformation, ...) of the collimators' jaws.
- A collaboration with the Kurchatov
Institute was launched for the modeling of the shock waves in collimators.
- As an outcome of the Controls Group
Review it was proposed that the collimators' controls will be staged.
- A meeting organised by the Machine
Protection Working Group on the quench limits of superconducting magnets
will be held on Friday September 30th.
- Thomas Weiler joined the Collimation Team
as a fellow starting from September 1st. MG will
add TW
to the invitation list of LOC meetings.
- SLM -> MG
- A proposal is made
to organise Group seminars to exchange information between the sections, and
improve the team spirit within the Group. Such seminars should be held
monthly. A list has been prepared with contributions expected from LOC
members.
- A
list of people
responsible for the commissioning of BDI systems was circulated by R. Jones.
He asked to have also names of people from ABP who could support the
commissioning. Such a list was already presented by OB at the LOC meeting of
15/03/05. MG will fill in the list provided by R, Jones taking into account
the available information and he will circulate the table for feedback from
LOC members.
- Summary of the second MAD-X day ->
FS
- Successful event: it has been proposed to
have a MAD-X day every year.
- Open points:
- Tracking: the five-dimensional tracking
is problematic.
- Matching: the matching with PTC is still
missing.
- Makethin: the issue of slicing solenoids
was raised.
- Matching with variable length between
magnetic elements: still not available.
- A work plan will be prepared and
presented in a forthcoming meeting.
- Feasibility of Adjusting Dispersion at the Injection Point in IR2 -> AK
(pdf file)
- The analysis made aimed at showing
whether it is possible to generate dispersion bumps at LHC injection to
improve the optical matching. The amplitude of the dispersion bump is about
10 cm.
- Using those orbit correctors in IR2 that
are not part of the crossing bump or separation schemes it is found the
required dispersion bumps cannot be generated.
- SF proposes to use MQTs to generate
dispersion waves, closed within the insertion, as tuning knobs.
- AOB
- HB reports that
Lionel Neukermans (LN) has joined the LOC team to work on the halo and tail
generation for linear colliders in the framework of EuroTeV. MG will add LN
to the invitation list of LOC meetings.
- SPS scrapers: compatibility between
LHC and high intensity beams -> HB (pdf
file)
- Following a
joint analysis made with G. Arduini, it turned out that the collimators'
settings to be used in the SPS both for the LHC beams and the
high-intensity proton beams for CNGS, are not compatible with each other.
A document will be prepared and a solution proposed.
Colour code:
- Black: proposed agenda
- Red: outcome of discussion at the meeting
Last update on 03-10-2005 18:15:00
MG