Sections:
Divers:
.
MA - Section meetings minutes
I- LHC-MMS-MA section meeting
Held on 12.12.2001, 14.30-15.45, duration: 1h15mPresents: Paolo Ferracin (PF) Arnaud Devred (AD) Giuseppe Gubello (GG)
Stefano Pauletta (SP) Marco La China (ML) Giulio Morpurgo (GM) VIttorio
Remondino (VR) Juan Garcia (JG) Walter Scandale (WS) Ezio Todesco (ET)
WS: Communications to section members:
Review on the critical issues and deadlines for the next months Situation of the personel. A new Ph.D. student, Alexandre Fellay, will join
the section from January 2001. He is having a Ph.D. at the EPFL on fiber
devices to measure temperatures. He will carry out the last year of his Thesis
in the Section. Summary of the activity of the Section members
PF: Ph.D. Student since 1999. AD: He has joined the section on a part-time basis in fall 2001. SP: He joined the section as a Technical Student in october 2001. His
master thesis will concern the analysis of the collared coil data to develop
an automatic code to control multipoles in the manufacturers. The code will be
implemented in the Excel worksheet used to load and to store the measurements.
GG: He joined the section as a Technical Student in november 2001. His
master thesis will concern the analysis of data on the geometry. Data of MMS,
MTA and CRI should be available for comparison. A software has been developed
to analyse MMS measurements. A dedicated experiment on Ansaldo 1/30 will be
carried out.
ML: He is Technical Student since 2000. He has discussed his Master thesis
in November 2001. He has analysed the flexural rigidity of the cold mass
through dedicated experiments, finite element model, and a analytical model.
He has also started an analysis of the thermo-mechanical behaviour of the
dipole during the cool-down. Presents: Arnaud Devred (AD) Juan Garcia (JG) Giuseppe Gubello (GG) Stefano
Pauletta (SP) Rob Wolf (RW) Walter Scandale (WS) Ezio Todesco (ET)
Special guest: Luca Bottura (LB)
Absents: Paolo Ferracin (PF) Marco La China (ML) (both at USPAS, Long Beach)
WS: Communications to section members:
Review on the critical issues and deadlines for the next months
The Machine Advisory Commitee (MAC) will be held in the 3rd weekend of
March. One main topic is the installation scenario: previous hypotheses based
on grouping magnets of the same assembler in the same octant is not valid any
more, since each factory will produce 1/3 of the dipoles. There is also a
strong interest in the possibility of mixing the cable producers. This would
speed up the production. In both cases the keypoint is the evaluation of the
uncertainty between producers.
Budget situation: MMS will have a cut of 20% Summary of the activity of the Section members
AD: schedule: at CERN till 25.01, from 04.02 to 15.02, from 25.02 to 01.03.
Work on the bad quench performance of Ansaldo 1 in collaboration with the
section of A. Siemko. There is a clear indication of two distinct families of
quenches. Work on the large variation of multipoles observed in Alstom 3 4 5
6: he is willing to analyze the available data on coil geometry, but the help
of Giancarlo is needed.
JP: Analysis of stability of Ansaldo 1 with Leica, in collaboration with
LHC-CRI. The magnet shows a good stability. One Smartex unit has to be
repaired Working on the systematic difference observed between measurements
with Leica taken on two sides of the magnet.
GG: Analysis of Leica measurements of Alstom 3. Working to acquire
experience and knowledge of ANSYS
ET: Working to write automatic codes to analyse an compare data of all the
collared coils and cold masses. An automatic tool is necessary since the data
flow is relevant. Warm magnetic measurements of 21 collared coil are
available. The correction of the signs based on the work of AD and on MTA data
has been implemented. Helping SP to define the macro to analyse collared coil
warm magnetic measurements.
SP: The macro to carry out the field quality analysis of the collared coil
at the manufacturer is close to completion. Limits have been set based on the
analyis of what has been produced so far. Two level of alarms have been
defined. He will learn some elements of magnetic field modeling and analyse
some cases of bad magnets.
RW: Preliminary analysis of variations between cable producers in
persistent currents. Copies of the talk will be distributed in the next
section meeting. Presents: Arnaud Devred (AD) Giuseppe Gubello (GG) Stefano Pauletta (SP) Rob
Wolf (RW) Alexandre Fellay (AF) Paolo Ferracin (PF) Walter Scandale (WS) Ezio
Todesco (ET)
Absents: Juan Garcia (JG) Marco La China (ML) (both at SM18)
WS: Communications to section members:
There has been an agreement to fix regular meetings between LHC-MMS-MA and
the section of L. Bottura to better coordinate the efforts for analysis
No decision has been taken on the new structure of the Division. The
external review will give his conclusions at the end of March.
Review of cables has been positive. Some concern has been expressed about
the schedule.
Three holding points have been introduced in the production by J. Vlogaert:
1) Decision about shim thickness before collaring 2) OK to proceed after
collared coil measurements 3) OK to proceed after cold mass measurements Our
section will be responsible for giveing answers on these points. Summary of the activity of the Section members
AF: Continuing his PhD thesis on the use of fiber optics to measure
temperature
RW: Results for the cable review: contract follow-up will be improved
Working on cable mixing. The cable schedule is linked to the mixing scenario.
Meetings with Bottura and Leroy will be organised to agree a presentation at
MAC.
SP: Upgrade of the macro to analyse collared coil warm magnetic
measurements: two versions, one for cern and one for the manufacturer. A
presentation will be given to the project engineers. He is analysing the case
of Ansaldo 2, also using simulations with ANSYS made by PF.
GG: Continuing PF work with ANSYS on dipole X-section. He is analysing how
a coil compresses under non-nominal shims in the case of infinitely rigid
collars. Next step: export results to ROXIE to evaluate magnetic field.
PF: Preparing two seminars: the final one for the PhD in Torino, and an LHC
Project seminar at CERN. Transferring to GG all the codes and knowledge about
ANSYS models and ROXIE. Two analysed problems: - Computation of the mechanical
and magnetic effect of midplane shims (in progress) - Effect of
electromagnetic forces on mechanics and magnetic field (still to be started)
AD: Analysis of aximuthal coil size measurements at Jeumont. 48 poles
available, i.e. 12 magnets. Average coil size available at 80 MPa. One
observes huge variations of plus minus 0.15 mm. 18 positions along the axis.
Different elements: Spigo does not manage to close the mould, change from
capton to apical. Some defects along the axis seem the same, this means that
one seems the tooling (curing mould) signature.
WS: Experiment on change of dipole shape induced by a lateral stress.
Presence of friction beyond what expected. Experiment on change of dipole
shape induced by temperature, for some dipoles in the string.
ET: New data from last meeting: 1 collared coil (Alstom 11). The macro to
make the analysis of all colaled coils is completed. Next step: have an
automatic analysis of also the cold data to get the correlations and to be
able to place the targets. Presents: Jerome Beauquis (JB) Giuseppe Gubello (GG) Stefano Pauletta (SP)
Walter Scandale (WS) Ezio Todesco (ET) Iouri Vanenkov (IV)
Absents: Arnaud Devred (AD) (In Paris) Paolo Ferracin (PF) (In Mexico,
holidays)
WS: Communications to section members:
From March 1st Iouri Vanenkov (staff scientist) has joined the section. He
has been previously in the Short Model section with D. Tommasini, working on
capacitive gauges to measure pre-stress, and then in the LD section with
Vlogaert, working on the machines to measure e-modulus and coil size.
From March 1st Jerome Beauquis (prac) joined the section. He has been
student with John Miles, working on the collar and lamination database. Then
he has worked with Giulio Morpurgo to create the Oracle databse for the
magnetic measurements. Now he will help wrinting code for the analyis of
magentic measurements data.
The Council is discussing new budget restrictions. The situation is not
easy.
At the machine advisory committee, the results of the first magnet with the
new X.section has been shown by Lyn Evans. Walter has presented the situation
for the geometry. Summary of the activity of the Section members
GG: He is analysing with a finite element code (ANSYS), developed in the
previous years in MMS, the effect of pole and midplane shims on the field
quality. He considered different approximations, such as infinitely rigid
collars, to compare these results with simple models based on current
distributions as they are implemented in Maelstrom and Bio'. He is also
studying the difference of geometric mesaurements between the Leica on the
connection and on the non connection side, trying to figure out the origin of
this difference and its compatibility with Leica specifications. He will study
the problem of the deformation due to Lorenz forces on the coil and their
influence on field quality.
ML: He is studying the dipole geometry, in particular the change of shape
induced by cool down transport and different ways of supporting it. He is now
analysing the problem of constraints on the dipole: experiments versus finite
element model results.
SP: The macro to analyse collared coil warm magnetic measurements has been
completed. Two versions are available, one for cern and one for the
manufacturer. A presentation
has been given to the project engineers. He is now working on some statistical
aspects, as normality tests. He is also studying techiniques to fit multipole
decay to work out an estimate of the distance of the error in a magnet with a
bad magnetic field. He will continue the analysis of bad cases up to the end
of march, then he will start writing the Thesis.
WS: He has partecipated to the experiment with ML to analyse the
interaction between cryostat and dipole cold mass. What happens during the
cool-down ? Is there friction of the cold mass is free to move ?
ET: New data from last meeting: 6 collared coil (Alstom 11 12, Noell 7 8 9,
Ansaldo 7 8). New data from last meeting: 2 cold masses (Alstom 4 5) All these
magnets have been accepted. The macro to make the analysis of collared coils
includes also an automatic loading of the MTA data at injection and high
field. Therefore control limits are automatically updated. The first magnet
with the new X.section, Alstom 13, has been measured. Results are positive: b3
in in the acceptance limits, and b5 and b7 should be within the limits or
close to them. More statistics is needed to precisely know the situation.
Future works: a log file of the holding point, a web site with the magnetic
measurements data. Presents: Arnaud Devred (AD) Jerome Beauquis (JB) Giuseppe Gubello (GG)
Stefano Pauletta (SP) Walter Scandale (WS) Ezio Todesco (ET) Iouri Vanenkov (IV)
Rob Wolf (RW) Juan Perez (JP) Marco La China (ML) Alexandre Fellay (AF)
Elena Wildner (EW) Paolo Ferracin (PF)
Special guest: Lucio Rossi (LR)
WS: Communications to section members: (15 min)
Elena Wildner has joined the section in April 15. She will work on the analysis
of magnetic measurements, mainly of cold masses, and on the dipole database.
Changes in the CERN structure: we will have two divisions to
handle accelerators: Accelerator Technology (ex-LHC) and Accelerator Beams (ex SL and PS).
Our division will have new groups names. The final structure will be defined in one-two
months.
LR: Innovations and mandate of the section (45 min)
Acknowledgements for the work of the section. The personnel has been first reduced
(dismissal of the activities on measurements) and now is is growing on the core activity:
analysis. Database is back in the mandate of the section: the last MAC was stating that
dipole database is a very critical point.
Some resources of the cable section could be shifted to help in the dipole database when
the cable database will be finished. A strict collaboration is needed on the quadrupoles
with Saclay. The interaction of the section members with the industry will have to go
through the project engineers of Jos (Main Dipoles) and Theo (Main Quadrupoles) Section.
Summary of the activity of the Section members (40 min)
ET: He has created the website of the group in collaboration with V. Remondino;
the page is now linked to the LHC web page. He has also created a web site
of the section; links to individual pages are available for section members.
The Field Quality observatory has been created as well: a web page with the
graphs of field quality in the collared coil and comparison to beam dynamic
targets. The template of the magnetic measurements has been updated to include
also the information relative to the holding point. Another collared coil with
the new cross section has been measured in Alstom: data of the previous magnet
are confirmed.
A template to make the separate analysis of the new and old X section is
available. Working with EW to build automatic tools for the analysis
of the cold mass. Working with JB to define automatic tools to analyse
measurements.
PF: He will leave CERN today, having finshed his Ph.D. thesis. He warmly thanks
all the colleagues; he will start a contract in LBNL magnet group in May.
IV: Still some duties with Jos Section (PPM machine). Discussion with AD on coil
measurements to agree on a common approach. Installing postprocessor for coil
geometric measurements data at the manufacturers and train people.
AF: PhD on optical fibers for temperature sensing. He finished to install these
fibers in Ansaldo 1 prototype. Data will be available in two months.
ML: Analysis of the dipole geometry. Numerical simulation to estimate the error
associated to the dipole axis measure, in collaboration with GG. Trying to relate
the errors of the hardware to the measured errors (discrepancies between axis
measurements on the two sides). Second activity: optical displacements
sensors (Smartex) installation.
SP: Writing the Master thesis, to be discussed in July.
JB: Working with ET and EW to make Excell tools to analyse magnetic measurements.
Oracle tables for magnetic measurements are nearly completed. Collared coils
data are loaded in Oracle.
GG: Working with ANSYS to evaluate the effect of Lorentz forces on field quality.
Second activity: analysis of the LEICA data about dipole axis. Non-negligible
difference in measurements from connection side and non connection side.
These differences can be interpreted as errors in the definition of the
reference system used in both sides.
JP: Providing data of the dipole geometrical axis for the analysis. Completing
installation of Smartex sensors in String 2. Measurement of Alstom 5 axis
(both dipole and spool pieces). Spool piece position depends on the Leica
results and on the stability of the cold mass axis.
EW: She has joined the section in April 15. She will organize the workshop on
geometrical stabilty. She will mainly work on the analysis of the cold
mass magnetic measurements and the related holding point. Moreover, she
will work on the dipole database.
RW: Estimating the correlations between magnetization and persistent currents, to
work out scenarios for installation. Mixing of cables seems to be a viable option.
AD: He has collaborated at 50% since 2001, he is not supposed to come in May,
a new contract will start in June. Working on the variation along the axis of the
multipoles in Alstom-Jeumont magnets. Visiting Jeumont, non-conformities of
the coil were found (outward displacement of a few tenths of mm) that could
explain the measured multipoles. Finding out reasons for these non conformities.
He also started to discuss with Iouri a monitoring tool for the coil size
measurements. Proposal of Iouri of using Fuji papers along the radial direction
during the elastic modulus measurements.
WS: At the end of the month there will be the first meeting of the Magnet Evaluation
Board. This committee should accept or refuse magnets.
Presents: Arnaud Devred (AD), Jerome Beauquis (JB),
Giuseppe Gubello (GG), Walter Scandale (WS), Ezio Todesco (ET), Iouri Vanenkov (IV),
Juan Perez (JP), Marco La China (ML), Alexandre Fellay (AF), Christine Vollinger (CV)
WS: Communications to section members: (30 min)
The Magnet Evaluation Board is active since two months. MMS is
represented by W. Scandale and D. Tommasini, E. Todesco being supplent member.
Christine Vollinger will join the section in September. Two students
(SP and GG) had or will have the discussion of their Master Thesis. There has been a
relevant incerase in the personnel during the past months.
Tasks of the section: holding points in the dipole production.
The holding point in the magnetic measurements is already active,
an holding point on the geometry will be activated. No holding points for
the quadrupoles are foreseen, but field quality and geometry will have to be followed up.
Tasks of the section: database. It is organised on a repository
and then in Oracle tables. There is an Access database for geometrical and mechanical
parameters of the collared coil (IV).
Tasks of the section: analysis of all available measurements,
understanding problems during the production, and feed-back on the production. Much
work has to be done: geometrical shape, shape of the magnetic axis, mechanical
parameters, correlations.
Tasks of the section: more academic activities - analysis of
transients in the dipole shape, temperature sensors by optical fibers.
Tasks of the section: handle instrumentation in the industry.
Tasks of the section: Communication. A monthly letter is already
done about collared coil field quality to the managment (ET), the same should be done for
geometry, mechanical parameters (IV), and assembled cold mass (EW).
AD: Necessity of having field quality plots separated according to the manufacturer.
Necessity of giving more information to the industries about the analysis that is
being carried out in the section.
Summary of the activity of the Section members (40 min)
ET: a web site containing the field quality plots has been activated
(field quality
observatory). A bimonthly letter on the situation of field quality and on the
steering of the production is issued bimonthly and sent to the management, project
engineers and technicians. Three papers have been published on international journals:
a paper on Phys. Rev. STAB on
the effect of shims on field quality, a
paper on IEEE on the
speckle interferometry to evaluate displacement of conductors, a
paper on IEEE on the
mechanical and thermal properties of the LCH dipole coil.
CV: She worked in ICP and is currently fellow in PS. Technical
student in MMS, she worked in the yoke design of the dipole under the supervision of
S. Russenschuck. Then, Ph.D. in ICP to calculate persistent current field errors.
She has now a fellowship in PS, working on superconducting cavities. She will join
the section in November.
JB: Working on tools for analyisis of collared coil and cold mass
field quality. Preparing software to upload warm magnetic measurements in Oracle.
Some work also to finalize table for geometry EW, Marta Bajko etc.
AD: Analysis of Alstom 5, limited to 6 T in the straight part.
The magnet was open at Alstom-Jeumont. In terms of assembly and mechanics the
disassembled magnet looks very good. Very good quality observed also in the coil ends.
The problem was the conductor: 28 cold welds in strands were found. This
explains the limit at 6 T. Next step: perform critical current tests.
Therefore, the problem was a fault in the QA of the cable.
JP: Measure of the geometry of cold masses. The first type A has
been measured. Preparing instruments for the industry to measure magnetic and geometric
axis. Helping MTA to measure axis through a mole and Leica with vacuum inside the
cryostat, to have a measure of the axis at cold.
AF: Writing the PhD thesis. New fibers to be tested at higher
temperature. A new test campaign will be done at high temperatures and at low
temperatures in cryolab.
MC: Analysing geometry at warm, cold, and during cooldown.
Experiment in the string with Smartex. Aims at comparing of data with finite element
model. Experiment to analyse.
GG: Analysis of geometrical measurements. Difference bewteen
connection side and non connection side. Study of the effect of Lorentz forces on
field quality. Writing the master thesis to be discussed in September.
IV: Two visit to companies (Ansaldo and Noell) to install the
software package for acquisition and storage of mechanical data. Now it is active.
A seminar has been given in MMS some weeks ago. Preparing for a monthly report about
mechanical data.
1)
Field quality analysis: integrated trasfer function.
2) Field quality
analysis: estimates of the uncertainty (i.e., variability between producers)
relevant to installation scenarios.
3) Geometry analysis: out of
tolerances, comparison between results from different groups.
Close to the completion of the Ph.D.
thesis, that will be finished in early January and discussed in February. The
thesis has concerned a magneto-mechanical analysis of the LHC dipole finalized
to the evaluation of the effect of mechanical deformations on field quality.
He would like to carry out the analysis of the impact of Lorentz forces on
field quality.
He will be in the section up to the end of April.
He is
analysing the problem of the quench location in Ansaldo 1/30, that showed bad
performances, using the MTA data at 1.9 and at 4.3 K. One of the issues is to
distinguish if the bad performance is due to a bad cable or to a bad assembly
procedure.
He is analysing the rather wide variation of the multipoles
along the axis in Alstom 3 to 7. (This variation has been mostly reduced to
usual values found in Noell and Ansaldo for magnets 8 and 9). He concentrated
on Alstom3, where one of the apertures shows a clear anomaly. He points out
that the problem is in one specific position and strongly influences b3,b5,a2.
A missing shim could be an hypothesis, but then some effect on the main field
should be visible, and this is not the case.
II- LHC-MMS-MA section
meeting
Held on 18.1.2002, 14.00-16.15,
duration: 2h15m (1h section meeting plus 1h15m Rob talk)
III- LHC-MMS-MA section
meeting
Held on held on 15.2.2002,
10.00-12.00, duration: 2h
Analysis of the geometry: reconstruction of the shape based on two
different procedures (MMS and EST). Comparison of the approaches.
IV- LHC-MMS-MA section
meeting
Held on 21.3.2002, 10.00-12.00,
duration: 2h
V- LHC-MMS-MA section
meeting
Held on 24.4.2002, 10.00-12.00,
duration: 1h 40m
VI- LHC-MMS-MA section meeting
Held on 26.7.2002, 10.30-12.00, duration: 1h 40m