Transcript emc - University of Illinois Urbana

Entrance Muon Counter et al.
P. Kammel
Dave’s
drawing
T0 150 mm
Mylar 126 mm
hex
m+
Thin, fast WC
helium
38 cm
hex
• issues beam time structure
beam properties on target, inc. stability
errant muons:
transition sneakers (=during kicker transition)
quiet sneakers (=during beam off)
missing muons (=not stopping in target for any reason)
• Base Line Configuration (BLC)
• performance and open questions
• (impact on systematics)  systematics section
• (kicker and overall channel properties) 
Initial beam properties of gercons (300 slit)
at target
p
x
5% FWHM,
no tails?
at beam window
<10 cm wide
Q:
!!
basic agreement to 02 data?
tails confirmed ?
p distribution confirmed ?
at which slit/rate settings ?
trade spot/p bin for intensity ?
which measurements in 03 ?
y
Scattering effects
Spreadsheet
Andrea’s and Cenap’s simulations
Cenap’s talk and study
spreadsheet summary
results
RC(um ) RC(m g/cm 2)
rad s (m m )
p
T
no w ires
28.199
3.76
600.58
135.31
0.100
12.93
FWHM
30.52
sm eared stainless
28.205
3.76
601.07
135.42
0.100
12.98
30.64
sm eared W
28.211
3.77
601.50
135.52
0.101
13.27
31.31
full stainless
29.239
4.05
684.28
154.17
0.114
24.75
58.42
full W
30.079
4.28
757.85
170.74
0.164
52.91
124.86
150 um scint
28.918
3.96
657.59
148.16
0.103
15.46
36.48
single GEM
28.945
3.96
659.80
148.65
0.107
19.39
45.76
BLC Layout
sketch of final beam tranport and target region
shape
material
element
L
ID
OD
beam pipe
~70 cm
30 cm
30.6cm cylinder
stainless
cylinder
stainless
provided by PSI
end flange
32 cm
1.7 cm
provided by PSI
37 cm
parts below provided by UIUC
reduction flange
stainless
37 cm cylinder
7.5"
1.7cm
flange should intrude ball so that 1" gap hex house remains
narrow beam pipe
stainless
cylinder
8"
7.5"
~40cm
length such that WC is positioned at inner surface of ball
perhaps we will step the diameter of this pipe
end flange with
vacuum window
wire chamber
stainless
cylinder
8"
6"
1"
ID is large as reasonable possible, Mylar window <100 um
1"
5"
6"
square frame
epoxy
exact dimensions to be worked out
window ring He bag
leave 1" air gap before and after wire chamber
consider design of scintillator as backup option
OD-0.01" 6"
1/2"
wall and window made of aluminized nylon, 0.001"
6"
6"
He bag
~40cm
window ring He bag
6"
6"
1/2"
Paul will try to exit window without endring to minimize material
target
4"
0"
0.1"
He bag length chosen so that target is in the center of ball
summer 02 configuration
CAD
inches
cad drawing
EMC requirements
comments:
rate and aging:
i) very hard, really necessary?
104 /mm2/s limit
pulsed effect??
CF4 mixtures (etching, recycling…)
Micropattern gas detectors GEM
i)
ii) fast gas, fast electronics
iii) ok
iv) needs study and experiment
ii)
project for 2003-2004 !
iii)
iv) efficiency:
•
•
•
constant (within ???) during 10-20 us beam OFF period after 2-4us pulse ON
efficiency stable within 10% during pulse
others ?
v) geometry:
•
•
total thickness < 100 um,
compatible with small space,relatively narrow frame, square or ring geometry
MWPC rate limitation
104 /mm2/s
HyperCP
MEGA
Fischer(85)
Johny’s
5 103 /mm2/s all CF4-isobutane(70:30)
3 104/mm2/s s=1.3mm, h=1.8mm, f=15um (W-Au)
1 105/mm2/s s=1.27mm, h=1mm, f=10um (W-Au)
`
s=1 mm, h=1.5 mm, f= ?um (W-Au)
CF4-isobutane
mobility 1.04 cm2/Vs
Ar-CO2
no hydrocarbons
MWPC gas
Ar-ethane
mobility 2.06 cm2/Vs
EMC signal & electronics
dE/dx in scint
50.00
dE/dx (MeV/cm)
40.00
30.00
20.00
10.00
0.00
1
2
3
4
5
6
E(MeV)
dE/dx ~ 8x mips
W~20-30 eV/ion pair, dE/dx mips=2-3 keV/cm
 100 e/cm for mips
only 1/2 integrated
 400 e/5mm for muons
for gain 4 103  8 105 e > 80 x rms noise (9500 e = 1.5 fC)
8 x threshold (105 e)
with rms noise 1500 e we would need only 500 amplification !
(for single cluster detection still 104 required)
EMC MWPC
2.5mm ?
1.5mm ?
from Fabio Sauli
GEM
GAS ELECTRON
MULTIPLIER
(GEM)
100÷200 µm
Typical geometry:
5 µm Cu on 50 µm Kapton
70 µm holes at 140 mm pitch
>105 part/mm2/s in multi GEM
F. Sauli,
Nucl. Instrum. Methods A386(1997)531
GEM DETECTOR:
- multiplication and readout on separate electrodes
- electron charge collected on strips or pads: 2-D readout
- fast signal (no ion tail)
- global signal detected on the lower GEM electrode (trigger)
A. Bressan et al, Nucl. Instr. and Meth. A425(1999)254
GEM
GAIN
Multiple structures provide equal gain
at lower voltage
The discharge probability on exposure
to a particles is strongly reduced
DISCHARGE PROBABILITY WITH a:
For a gain of 8000 (required for full
efficiency on minimum ionizing
tracks) in the TGEM the discharge
probability is not measurable.
S. Bachmann et al,
Nucl. Instr. and Meth. A479 (2002) 294
The total length of the detected signal corresponds to
the electron drift time in the induction gap:
Peter:seem
s short to
me ?
Full Width 20 ns
(for 2 mm gap)
Induced charge profile on
strips
FWHM 600 µm
Good multi-track resolution
GEM
Two orthogonal sets of parallel
strips at 400 µm pitch
engraved on 50 µm Kapton
80 µm wide on upper side,
350 µm wide on lower side
(for equal charge sharing)
400 µm
80 µm
Peter: probably we would do that with wires
350 µm
400 µm
Backup (or BLC?) EMC
scintillator
(partially) Integrating chamber
Q:
•
rough profile measurement during
pulse on
•
veto function during pulse off
keep light separate in scint and guide
joint scint to light guide
make first bend
adiabatic or fiber light guide
Target
target material
• Ag
• Sulfur
• Rust ?
• Xe
• Holmium
•?
compile information and references
coating material
•?
optimal errant muon catcher
arrangement
•
Diagnostic target detectors
Fast, segmented active target and anti counter
small scanner
Si detector
To answer basic questions
• determine errant muons n(x,y,z)
• measure their effect
Magnet
study optimal field requirements
study importance of shadowing, absorbtion
study importance of field variation, reversing, rotating, solenoid …
design choices: cos(theta) magnet
• saddle coil magnet (Ken’s magnet)
• permanent magnet
–
–
–
how important is homogeneity
what has been achieved
can we improve it
f=14 cm, L=30cm, wire=
Conclusions and work
EMC:
• how to realize high rate MWPC (BLC)
–
–
–
Design new optimized chamber
technical issues:
geometry and space, construction, tolerances,
frame, electronics
cooperation issues:
UIUC must lead and contribute (design,
communication, CAD, specs & order, electronics)
PSI will support (design, infrastructure), don’t
overstrain relation
test existing chamber with proper electronics ?, NO
how to simulate pulsed beam
• scintillator (backup 2003)
–
prepare !!
• is single GEM feasible option? (backup 2004)
–
–
–
–
–
scattering
less Cu?
gain and noise
pulse length (pile-up)
interest Johny, Sauli et al.
• work out basic systematic questions mentioned
–
–
–
real beam properties
effect of errant muons
requirements for EMC
other issues:
• target
• magnet
• BLC geometry
• detailed July measuring plan
•
•
including open beam issues addressed in this talks
plan, prepare instrumentation for that
timeline
•
spreadsheet
• Active Area 30.7 x 30.7 cm2
• 2-Dimensional Read-out with
2 x 768 Strips @ 400 µm pitch
• 12+1 sectors GEM foils
(to reduce discharge energy)
• Central Beam Killer 5 cm Ø
(remotely controlled)
• Total Thickness: 15 mm
• Low mass honeycomb support plates
B. Ketzer et al, IEEE Trans. Nucl. Sci. NS-48(2001)1065
C. Altumbas et al, Nucl. Instrum. Methods A490(2002)177
Gas Electron Multiplier EMC
HERA B version
Triple GEM with pad readout for LHCb muon
detector
G. Bencivenni et al, Nucl. Instr. and Meth. A478(2002)245
mLan experiment:
Precision Muon Lifetime Measurement
University of California at Berkeley
Boston University
University of Illinois at Urbana-Champaign
James Madison University
University of Kentucky
mLan
@PSI
Scientific case: m+ lifetime + GF
1
m

GF2 mm5
192 3
(1  q )
GF
g2

(1  r )
2
2 8M W
radiative corrections,
higher order QED
precision EW physics
quantum loops
• fundamental constant of nature
• dominant theoretical error (16 ppm) reduced to <0.3 ppm (2-loop, ‘99)
• impressive predictive power in EW sector
m+
• dramatic improvement in other EW parameters
quantity
Fermi constant
Fine-structure
constant
Z boson mass
symbol
GF
a(0)
a(MZ2)
MZ
value(error)
1.16637(1) 10-5 GeV2
1/137.03599976(50)
1/127.934(27)
91.1876(21) GeV/c2
W+
t
b
nm
W+
e+
ne
(ppm)
9
0.0037
210
22
experimental efforts at RAL (Riken) and PSI (FAST, mLAN)
mLan
Cascaded GEMs permit to attain much larger gains
before discharge
Double GEM
Triple GEM
C. Buttner et al, Nucl. Instr. and Meth. A 409(1998)79
S. Bachmann et al, Nucl. Instr. and Meth. A 443(1999)464
mLan summary*
Determine m lifetime to 1 ppm
– This yields GF to <1 ppm
– Helps gp determination from
m+ / m- lifetime difference
•
PDG Average = 2197.03 +/- 0.04 ns
Value - PDG Average (ppm)
•
150
100
50
mLan goal
Require
-50
– 1012 good events
Bardin
– Pulsed low-energy muon source (Kicker)
– Symmetric, segmented timing detector
•
Giovanetti
Balandin
Duclos
Run Plan
–
–
–
–
–
mLan
5
0
Beam tests and modeling:
Detector prototype tests:
Install complete experiment:
Running for physics data:
Additional running:
June 00, July 01, Dec. 01, July 02
June 00, July 02
Summer/Fall 03
Summer 04
Summer 05
*Courtesy D. Hertzog
mLan concept
Quads
Kicker Plates
N
S
+12.5 kV
0
-12.5 kV
mLan
• statistics Ne=some 1012
in standard DC beams only one m at a time,
rate limitation, several years of measurement
pulsed beam, radioactive source mode
Beam development E3
sep
mock
kicker
exp. milestone achieved ’02
extinction 3x10-4
rate ~30 MHz
mLan
10-3
Detectors and Structure
e+
mLan
180 triangular double
layer scintillators
arranged in soccer ball
geometry