Agenda for 19 Dec 2006 SWMD Telephone Meeting
Minutes
of 06-Dec-2006 meeting
Present: Luis Fernandez, Steve Molloy, George Ellwood, Roger Barlow,
Andre Sopczak, Adriana Bungau
Brief reports on:
- T-480 Data analysis et al.
Discussion of the impact of energy errors in the reconstructed
kick angles. See plot of energy measured vs. pulse
number (absolute calibration uncertain). Suggested to detect the
rapid rise region and exclude pulses in the vicinity of such an
instability, e.g. 9040-9100 in this plot. Other plots in this directory show the
*average* energy reconstructed from all pulses at a given
collimator vertical position, superimposed on the reconstructed
deflection from the same pulses. Comment was that the average
energy does not contain all of the information, and could allow
some lower quality pulses to be used in the angular reconstruction,
therefore suggestion is to exclude these. Suggestions for
algorithms to detect rising edges, and also to look at the
Mathworks
file exchange area for examples which may be useful.
- Wire Tests
- Wakefield Simulations
Roger Jones / Graeme Burt have access to a version of ECHO-2D
from Igor Zagorodnov.
- Merlin Simulations - Emittance
Dilution due to Wakefields - Adriana
Studied effects of higher order modes as function of beam offset
at entrance to BDS (SP2 in ILC 2006e deck), y half-aperture is
0.5mm, considered offsets in y between 0.05mm and 0.45mm. Higher
order modes diverge from lower order predictions for offsets greater
than 0.25mm, below this the simpler treatment appears sufficient.
Q (NKW): would it be adequate to use lowest order treatment for most
purposes, and consider higher modes only for study considering
machine protection where *very* large offsets are important? For
"routine" operation, such large offsets would not be expected. To
discuss next meeting?
- Collimator designs and manufacturing
- 2d
shockwave analysis,
SEQV.wmv -
George
Now reflected shear waves are seen in simulations, these are
the more damaging of the compressive and tensile waves, and depend
on their angle of incidence relative to the material surface. Side
effect is that the angle of any linear taper ought to be fixed
before definite conclusions can be made about damage, and also
whether we expect it is necessary to have high conductivity coating
on the surface of e.g. Ti alloy.
- sandblasting: "Hi George
Sandblasting these components will increase the surface roughness and
the total surface area, which will also increase the total outgassing
rate and gas load of the system. It is also more difficult to remove
dirt and cleaning fluids from rough surfaces, this can give problems
at high vacuum pressure below 1x10-3 mbar and UHV systems.
If your system is operating between atmosphere and 1x10-3 mbar, there
shouldn.t be any problems with the rough surface finish of these
items. A simple degrease followed by demin water rinse and drying will
be ok."
- td-1097-006.pdf
- td-1097-010.pdf
- td-1097-011.pdf
- td-1097-012.pdf
- td-1097-013.pdf
- td-1097-014.pdf
- td-1097-015.pdf
- td-1097-016.pdf
NKW note, ESA vacuum is nominally 10-5torr.,
i.e. ~10-5mbar, so the roughened collimator may need
additional treatment, based on the information George had
obtained. Should encourage us to ship collimators to SLAC early...
AOB:
- Material damage: NKW had discussed plans for damage
tests with Lew Keller as neither ESA or TTF2 were ideal to study
damage of Ti alloy in the regime we are most interested in. To
discuss further after the LC meeting at Daresbury, 8-9 Jan..
Lew had asked Sasha Drozhdin and Frank
J. if it would be possible to re-evaluate the thicknesses assumed
for spoilers (defaults 0.6/1.0 rad. lengths).
- Meetings:
- Astracts submitted to PAC'07 (New Mexico, 25-29 Jun 2007),
see here
- EUROTeV workshop, Daresbury, 8-9 Jan., talks on:
- Other relevant meetings?
- Next meeting - 25 Jan. 2007.
