Transcript klm_summary-nov2010

KLM at Belle-II
P. Pakhlov
(ITEP)
Test of long strips
(R. Mizuk, I. Tikhomirov)
For TDR we used short strips (no
long strips were available) and
extrapolated light yields using
measured attenuation in the Y11
fiber.
Improve groove preparation:
Vladimir: saw rounded groove
Fermilab: found encrustation on the groove
wall  brush groove mechanically
difficult to avoid air
bubbles in the optical gel
around corners!
Cosmics test setup
triggers
SiPM
readout
4 strips tested
simultaneously
mirrors
25cm
2.8m
Longitudinal profile of light yield
corrected for SiPM internal interpixel
x-talk and non-perpendicular incidence
thickness=10 mm
= 7 mm
value in TDR
for both Fermilab and
Vladimir
Light yield is slightly better than
reported in TDR. Improved
production technology?
Both Vladimir and Fermilab strips allow to achieve
goal of 99% efficiency at 7.5 pixel threshold at far
end..
Module-0 (full size quadrant)
The main concerns before starting mass production is
- to check geometrical compatibility with support structure, electronics and
cabling (to fix all strip sizes) and rigity of the construction;
- to elaborate operations for mass production, assembly and installation.
Initial plans:
- construct by November’10;
- cosmics tests in November, then send to KEK by the end of 2010
The start of production was delayed by 2 months. The current status:
- all strips and fibers are prepared
- gluing of fibers has started (takes ~ 1month)
- gluing of strips to substrate (fast operation ~ few days)
- support structure will be prepared in ITEP for Module 0 and sent
together with scintillator segments to KEK.
- technician and engineer from ITEP will come to KEK for assembly after
module arrival to KEK (February-March)
Fibers are prepared
- cut with actual length
- both ends are milled and
polished
- one end is mirrored
- the other glued to connector
Strips
with real lengths are prepared
Support structure
5-9 mm
- Net of x-y I-bars, where
scintillator segments are
inserted.
- After installation of
segments the whole structure
is fixed to the existing frame
with L-bars, screwed (welded)
to the frame.
- Preamplifier boards are
fixed to the frame.
- Al (polyethylene) covers are
screwed to the net.
- Cables are interlaid in the
gap between I-bars net and
cover
frame
y I-bar
x I-bar
welding
at junction
Electronics
Current status
EKLM Mass production
 The estimated time for whole EKLM production ~ 1.5 year.
 Should finish production by the end of 2012
 Divide the production into several (3) batches to start installation
earlier
To start
EKLM Mass production
we need
 Check performance with module-0
Should done by starting of
 geometry
mass production
 rigidity
 assembly and installation
 Take decisions:
Should fix by January’11
 thickness? 7mm -10mm
to start production in May
 strip producer (Vladimir/Fermilab)
 Produce machinery:
 tool for gluing fiber to the groove (filling groove with optical gel)
 press for gluing strips to substrate
 Buy all necessary materials (at least ⅓ of the whole amount to start)
 strips (90 k$ for 3.3 tonne (⅓))
 Y11 fiber (48 k$ for 12 km (⅓))
 SiPM (8 kCh have been bought already (>⅓))
 miscellaneous (SiPM housing, optical gel, glue, substrate) mostly
available
Choose strip producer
Fermilab (USA)
Vladimir (Russia)
Almost identical light yield (with the equal thickness)
Almost identical price (~25$ Fermilab; ~28$ Vladimir)
+ 20% for transportation
+ 20% taxes (if ITEP buys it,
probably taxfree if granted)
+ ~40k$ for new die
Production (extrusion) time of whole amount for EKLM = 3 months
+ 9 months for sawing into strips
Central groove is easier for
filling with optical gel
(pumping inside), still not
clear how to brush groove
quickly
Barrel KLM replacement?
Can RPC work at higher bg environments?
(Y. Yusa)
-At forward edge the low MuId efficiency in barrel can be partially
recovered by EKLM
- At backward side, where muons are soft, significant loose of
acceptance for muon identification
Can RPC survive for another 10 years of operation?
After disassembling of
EKLM. April’11?
Partial replacement (few innermost layers) is very likely;
Full replacement... this may happen
Need to prepare design, schedule, think of installation procedure
- barrel ECL cables (only at forward part): mount/dismount
from the backward side, except for upper octant (chimney)
- have to remove
kite holder. This
operation should be
very well thought
out.
If no full replacement maintenance work is required to reduce dead region.