Transcript TOF

M. Bonesini
Updates
onMilano
TOF
INFN
M. Bonesini - MICE CM18 RAL
16/06/07
project
1
Outline
Hot topics



TOF0/1 counter construction
Installation issues
TOF1/2 PMT shielding
TOF software/simulation
TOF readout
Conclusions
M. Bonesini - MICE CM18 RAL
16/06/07
2
Hot issue: detector construction
Material procurement:



PMTs delivered
Scintillator delivered
Electronics in delivery
Counter assembly: mount & calibrate detectors with
cosmics. Here we have delays (1-1.5 months)


Production of lightguides (70% done) + glueing in external
firm (ALPEAT To) not yet finished
Final counter prototyping is fine (PMTs holders, light
tightness, wrapping). Still lacking to finalize laser light
injection system into counters: tests in progress to use a
laser diode instead of a more expensive Nd-Yag laser
Detector plane assembly: X/Y planes in a rigid
structure. Define “interface” with supports
M. Bonesini - MICE CM18 RAL
16/06/07
3
TOF installation issues
Tof station detector
structure
M. Bonesini - MICE CM18 RAL
16/06/07
4
TOF0 support (with CKOV)
Thanks to Ghislain and Wing
M. Bonesini - MICE CM18 RAL
16/06/07
5
Space take up for the combined Cherenkov & TOF0
Thanks to Wing
M. Bonesini - MICE CM18 RAL
16/06/07
106
Hall space available to the Ckov &
TOF0
Beam line
Thanks to Wing
Main concern: access
to detectors … 25 cm
M. Bonesini - MICE CM18 RAL
width is a problem
16/06/07
3
7
TOF1 cage
Problems:
• cabling (HV,
signal, calibration
fibers …)
• checks with 3-D
calculations: TOF
PMTs with mumetal shielding can
bare only B// up to
~ 60 G
M. Bonesini - MICE CM18 RAL
16/06/07
8
A small very useful request from
EMCAL and TOF2
Here we require a
cable by-pass under
the new MICE Hall
floor for EMCAL+TOF2
and a basement level
hole in the wall for
cables
M. Bonesini - MICE CM18 RAL
16/06/07
9
PMTs tests: conventional PMTs
shielding
 TOF0 PMTs requires no shielding, aside 1
mm m-metal due to small B field (B << 50
Gauss, Kevin private communication)
 TOF1/2 even after the 100 mm global iron
shielding needs some additional shielding
to use conventional PMTs (as B// ~ 200-300
G, B _|_ ~ 1000 G)
M. Bonesini - MICE CM18 RAL
16/06/07
10
Problem: R4998 can bare Bperp but not B//
B//< 50 Gauss fine; B_|_ < 100-120 Gauss fine eventually additional
m-metal or soft iron
M. Bonesini - MICE CM18 RAL
16/06/07
11
B field with one 100 mm iron
shield (current design)
M. Bonesini - MICE CM18 RAL
16/06/07
12
My old transparency at RAL CM16
B field is ~ 200-300 G
//; ~ 1000 G _|_ at
r=30-35 cm (PMTs
position)
• I doubt it can be shielded
with individual PMTs shields,
preserving good timing
properties
BUILT: coil with 5
windings for fields up to
700-800 G
• this point to 2nd shield, but
we will try to test PMTs
“exotic shieldings” by
building a 400 G lab solenoid
M. Bonesini - MICE CM18 RAL
16/06/07
13
Advocated solutions:
Solution A (“Ghislain cage”): extra
shield (50 mm) connected with joints to
first shield (100 mm) and local shielding
of PMTs (m-metal only if 420 mm hole)
Solution B: no-extra shield but heavy
local shielding of PMTs a la D0 (test
magnet delivered now at Bicocca)
M. Bonesini - MICE CM18 RAL
16/06/07
14
D0 tests (note # 2706)
Problems:
• It will work for R4998 1” PMTs?
• Tests to be done for Gain +
timing
See some results later
M. Bonesini - MICE CM18 RAL
16/06/07
15
R. Bertoni, M.
Bonesini
INFN MIB
M. Bonesini - MICE CM18 RAL
16/06/07
16
• Laser source (Nichia Blue laser diode + up to 1MHz
Avtec fast pulser: signals 100 ps- 2 ns)
• field up to 470 G (now: 40A power), to go up to 700800 G with new power supply (on loan)
• signal comparable to BTF (~ 500-700 mV)
• Use of different shieldings: mu-metal only, additional Fe
M. Bonesini - MICE CM18 RAL
shielding, …
16/06/07
17
R4998 PMTs: Fe box shielding
M. Bonesini - MICE CM18 RAL
16/06/07
18
PMT tests results: B//
M. Bonesini - MICE CM18 RAL
16/06/07
19
0 cm
Extending the Fe box
beyond the mu-metal
shielding makes it
much more effective
M. Bonesini - MICE CM18 RAL
16/06/07
20
G. Gregoire Shield
From presentation by G. Gregoire at PC-224 and J.Cobb at PID // session
 Close outer gap between to discs; thicker 2nd disc (50mm)
Somewhat more complex – engineering / mounting TOFs….
M. Bonesini - MICE CM18 RAL
16/06/07
21
M. Bonesini - MICE CM18 RAL
16/06/07
22
B_r
-- 500 gauss
B_z
500 gauss
G. Gregoire scheme gives
very effective shielding for TOF1/2
M. Bonesini - MICE CM18 RAL
16/06/07
23
M. Bonesini - MICE CM18 RAL
16/06/07
24
A full 3-D
calculation (TOSCA)
in progess. Useful
to check “small”
effects, such as
working holes …
Remind max B//~
60 G with mu-metal
only
M. Bonesini - MICE CM18 RAL
16/06/07
25
Laser calibration + electronics
CAEN FADC (V1724) not yet delivered, but
work going on on firmware
Pavia group may probably take care of the
NINO chip “affair” (this solution is preliminary
to any serious thinking about SW: to free the
CAEN V1724 FADC used now by TOF)
some work on laser light injection in
progress with MEG (to allow use of a cheaper
laser diode, such as Hamamatsu PLP10): this
requires to maximize laser injection efficiency

Tests to be done soon with alumized bi-prisms
M. Bonesini - MICE CM18 RAL
16/06/07
26
TOF simulation studies from Yordan
Simulation and Digitization of the TOF sector are completed
Reconstruction for the simulated data is completed
TofHit, TodDigit, TofSlabHit and TofSpacePoint objects with the
relevant pointer links between them are present in the output of the
reconstruction
The new code is committed in the packages Persist, DetResp,
DetModel, Interface and Recon.
We are open for ideas for improvement, for example implementation
of dependence of time resolution on the position of the hit in the bar,
or anything else.
From Y. Kharazdov presentation at PID meeting
M. Bonesini - MICE CM18 RAL
16/06/07
27
TOF simulation
Positions of the hits in the TOF stations taken
from the Simulation
TURTLE beam is used
Configuration for stage 6
50 000 events are simulated
M. Bonesini - MICE CM18 RAL
16/06/07
28
Comparison of the times from Simulation
and Reconstruction
This time difference is obtained by using 100 ps intrinsic time
resolution for each PMT.
This means that we expect 100/sqrt(2) ~ 70 ps intrinsic time resolution
for each bar
and 70/sqrt(2) ~ 50 ps intrinsic time resolution for each station. This
fits very well with what we see in the plots.
M. Bonesini - MICE CM18 RAL
16/06/07
29
Conclusions
TOF0/1 counter construction is progressing;
readout scheme worked out; software issues
tackled
some installation issues to be spotted out
laser calibration system to be finalized
still some delays arising from INFN situation
not fully worked out (NTA approval, funding
[up to now we are at 0 E] …)
M. Bonesini - MICE CM18 RAL
16/06/07
30