PLEASE REPLY - IF POSSIBLE BY BY 1 AUGUST - TO THE WWS CO-CHAIRS (BRAU,
If you find you cannot answer any of the questions, as put, please tell us
why and give whatever relevant information you can.
There are, of course, many more questions to be answered and studies made
before the ILC CDR at the end of 2006. The MDI group's report at
(http://www.hep.ucl.ac.uk/~djm/MDIpanelreportJune05.doc) gives a fuller
overview of the issues to be addressed.
- What factors determine the strength and shape of the magnetic field in
your detector? Give a map of the field, at least on axis, covering
the region up to +-20 m from the IP. What flexibility do you have to
vary the features of this field map?
- Provide a GEANT (or equivalent) geometry description of the detector
components within 10 meters in z of the IP and within a radial
distance of 50 cm from the beamline.
Would you mind if the baseline bunch-spacing goes to ~150 ns instead
of ~300ns; with ~1/2 the standard luminosity per crossing and twice as
- For each of your critical sub-detectors, what is the upper limit you
can tolerate on the background hit rate per unit area per unit
time (or per bunch)? Which kind of background is worst for each of
these sub-detectors (SR, pairs, neutrons, muons, hadrons)?
- Can the detector tolerate the background conditions for the ILC
parameter sets described in the Feb. 28, 2005 document at
Please answer for both 2-mrad and 20-mrad crossing angle geometries.
If the high luminosity parameter set poses difficulties, can the
detector design be modified so that the gain in luminosity offsets the
reduction in detector precision?
What is your preferred L*? Can you work with 3.5m < L* < 4.5m?
Please explain your answer.
What are your preferred values for the microvertex inner radius and
length? If predicted backgrounds were to become lower, would you
consider a lower radius, or a longer inner layer? If predicted
backgrounds became higher, what would be lost by going to a larger
radius, shorter length?
Are you happy that only 20mr and 2mr crossing angles are being studied
seriously at the moment? Are you willing to treat them equally as
possibilities for your detector concept.
Is a 2mr crossing angle sufficiently small that it does not
significantly degrade you ability to do physics analysis, when
compared with head-on collisions?
What minimum veto and/or electron-tagging angle do you expect to use
for high energy electrons? How would that choice be affected by the
crossing angle? How does the efficiency vary with polar angle in each
What do you anticipate the difference will be in the background
rates at your detector for 20mr and for 2 mr crossing angle? Give
you estimated rates in each case.
What is your preliminary evaluation of the impact of local solenoid
LCC note 143)
inside the detector volume, as needed
with 20mr crossing angle, on the performance of tracking detectors
(silicon, and/or TPC, etc.)
Similarly, what is you preliminary evaluation of the impact of
compensation by anti-solenoids (
LCC note 142) mounted close to the
Do you anticipate a need for both upstream and downstream polarimety
and spectrometry? What should be their precision, and what will the
effect of 2 or 20 mr crossing angle be upon their performance.
Is Z-pole calibration data needed? If so, how frequently and how
much? What solenoid field would be used for Z-pole calibration? Are
beam energy or polarization measurements needed for Z-pole
Would you like the e-e- option to be included in the baseline, and
if so what minimum integrated luminosity would you want?
What will be your detector assembly procedure.
What size is required for the detector hall?