Time of Flight (ToF) Measurements - IRTG Heidelberg

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v= ∆t
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t =
m = p
dm
m
∆t
=
l
βc
=
l
c
dp
p
2
c t
2
l
1
2
2
+ γ
−1
1 1
−
β β
dt
t
2
+
=
dl
l
l
c
/" ! (
0 ! ! " 0 "
)! ! O
γ =
β =
βγ =
2
1
2
1−
β
1
1−
2
γ
p = γβm
E
= p
2
γ −1
2
0
c
2
+ m
2
c
4
2 2 2
2 2 2 lc 2 2
( 1+
m1
c / p − 1+
m2c
/ p ) ≈ ( m1
− m2
)
2 p
2
ToF difference (ns)
10
1
-1
10
-2
10
-3
10
e/ π
π/K
K/p
p/d
Path length 1 m
P
(GeV/c)
2700 ps
850 ps
300 ps
30 ps
1 lab
10
2 / ' ' $ $A
σ ;
σ
σ N;
σ );

M !
beta vs gamma
ñ
1/ñ
;M !
1
0.8
0.6
0.4
0.2
-4
10
! "
1 10
γ
1/beta vs momentum
10
1
-3
10
-2
10
)
! !
e π K p d
-1
, 5;
10 1 10
P (GeV/c)
!" ) ! !"
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Q "
K/pi ToF smearing
Yield
Normalized ToF (ns)
1400
1200
1000
800
600
400
200
0
-1 -0.5 0 0.5 1 1.5 2
Normalized ToF (ns)
1
-1
10
IB! ) A $)!! "
$ & $ !" "
Momenta vs ToF random
7& 77& 7&
0 0.2 0.4 0.6 0.8 1
P (GeV/c)
Q "
K/pi ToF smearing
Yield
Normalized ToF (ns)
1200
1000
800
600
400
200
-1
10
0
-1 -0.5 0 0.5 1 1.5 2
Normalized ToF (ns)
Momenta vs ToF random
1
0 0.2 0.4 0.6 0.8 1
P (GeV/c)
Q "
K/pi ToF smearing
Yield
Normalized ToF (ns)
1000
800
600
400
200
-1
10
0
-1 -0.5 0 0.5 1 1.5 2
Normalized ToF (ns)
Momenta vs ToF random
1
0 0.2 0.4 0.6 0.8 1
P (GeV/c)
, 5; , 5; , 5;

, " ) / "!
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8 #
,
$ "!) )
9
)
- !"
!
!

Stop
Start
$ " !
#" !"
' !"
Disc
Disc
! " ) " )
TDC
450 ns
100 cm
300 cm
Particle Trajectory
20 cm
400 cm

γ
&
) ) ) L " ! !"! "
Photocathode
−
Electrodes
Anode
Dynodes
Gain ~ 10 6 - 10 7

:
$ " ! "
C
1 $
I " !
! !"
! !+
" ! "! " "
I " ) !
;
J!@-
IB " γ "
M '
$ 0 !+
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$ "σ < 7& +

Glass
HV
z
,- 2 )
&
! !
/ % $( ) $
, , )!/
,!! , ! - !
3 , ! - !
,,#-
,-
!3!!"
HV cathode
Y
Spacers
Multistrip anode
, ' 2 )
,,#- )

σ t~5 ns
3 , ! - !
+
Trigger RPC developed in 1981
by R.Santonico and R. Cardarelli
Development of Resistive Plate Counters
Nucl. Inst. and Methods 187 (1981) 377-380
σ t~3-4 ns
Multi Gap RPCs started
by E.C. Zeballos et al
A new type of Resistive Pate Chambers :
The Multigap RPC
Nucl. Inst. and Methods A 374 (1996) 132
σ t ~50 ps
Timing RPC started
By P.Fonte A.Smirnitski, M.C.S. Williams
A new high-resolution TOF technology
Nucl. Inst. and Methods A 443 (2000) 201-204

* + ,-
- " 2 +
)! " !
!"
, , 0 σ T )
# 3!"! A
U V I; B
$ ) +
! +
& !3!"! A
,
!" ! +
! !
!" ! + B) "
) !"
IB! ) A
):-;(:)
$R V
- !"" V
σ T )
σ ϕ T
25;! (:)
$R V
- !"" V
σ T )
62= 1
$R V :
- !"" V
σ T )
' T R;
$ " A
!
+ /A
,,#- σ T )
, 3 σ T )
,- σ T "
,- σ T )

Trigger RPC
Cathode
Anode
0 ,- 0 /.
-10kV
x=2mm
0kV
Timing MRPC
-12kV
-8 kV
-4 kV x=0.3mm
0kV

-12kV
0kV
0 ,- 0 /.
0kV
-6 kV
-6 kV
$" !/ " ! " & !/ " ! " "

+) !0" 0 ! ! !
/" 2
$ ! !" W
3 $
$" " W
& "! W
0 ! " ,- .
Glass
HV
z
6 " $
! )! 0 !" ! "
# " )!
! )! 0 ! )) !)
HV cathode
Y
Spacers
Multistrip anode
1& " " 2 :
2 $
,! X?
$" )
) >;

#3!!" " I2
2 " ! )! !
" !" ) 3 "
"!3!!" 2 "+!3!!" !
! ! 0 "
" "! " B "!
I " !3!!" "
J4J !B
- ) 3 " " ! "
! " "!3!!" 0+
! ! !" !
"!

λ
λ=1/ α
α=σ ionisationN A /V mol
T-RPC α~10/mm
MRPC α~100/mm
!3!!"
T-RPC C 2F 4H 2/isobutene/SF 6 97/2.5/0.5
MRPC C 2F 4H 2/isobutene/SF 6 85/5/10
J B 4J 9 αB
α 4 0" " "
η 4# ! " "
α2η 4I 3 0" " "
B 4& !"
α = 13/mm
η = 3.5/mm
W.Legler Die Statistik der Elektronenlawine
In elektronegativen Gasen bei hohen Feldstärken
Und grosser Gasverstärkung, Z. Naturforschg.16a
(1961) 253-261

,- " O ! +
T-RPC E~50 kV/cm
MRPC E~100kV/cm
σ t = 1.28255/(α-η)v
α= Townsend coefficient
η=Attachment coefficient
α-η = Effective townsend coefficient
v= Drift velocity
T-RPC σ t ~ 1ns
MRPC σ t ~ 58ps
T-RPC v~130 µm/ns
MRPC v~220 µm/ns
W.Riegler et al: Detector physics and simulation of
resistive plate chambers. NIMA 500 (2003) 144-162

Efficiency/gap
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
I "+!" !) R
1
0
, "
0 0.1 0.2 0.3 0.4
Gas gap (mm)
Isobutane (IB)
C2H2F4 (TFE)
TFE+IB+SF6
Methane
ε = 1− ( 1−
ε
total
Gap
/ & & ε / & ε
)
n
Gap
: < >
? : < >>
==
? >=
>>
? ? =?
? =<
= ? >=
? >>

! )
0 " " ,-
!"3! 3! +! !
" A ! )! 0 ! ! < " 0 " " $-I " ! "P
* " ! "P
$-I ! 3 Y !( ! !" !) ! ) !
!+5&& .-"=0
*

! 0!

ALICE
Pad-Anode
MRPC
σ t

Beam
BARREL
CDC
x
', ,- !
+
y
z
HELITRON
MAGNET
PLASTIC WALL
1 m
? 5;
P Lab [GeV]
5;
, !
10 -1
Central Au-Au collision
at 1.45 AGeV has ~60particles
in the acceptance
of the proposed MMRPC barrel
This needs a granularity of
700 cells (2500 strips)
1
T
D
P
K +
1.93 AGeV 58 Ni+ 58 Ni
π +
0 5 10 15 20 25 30 35
Velocity [cm/ns]
5 + ;"

Glass
HV
z
HV cathode
Y
Spacers
Multistrip anode
Global MMRPC parameters:
Gas : C 2 F 4 H 2 /isobutene/SF 6 85/5/10
E-Field ~ 100 kV/cm
Spacing ~ 220-270 µm
Glass ~ 0.25-1.1 mm
)2 ,- " " )
Multi-strip anode:
x pos = (t 1 -t 2 )/2 • v s
t m = (t 1 +t 2 )/2
0 V
-10000 V
-10000 V
Timing:
σ t = 1.28255/(α-η)v
α-η = Effective Townsend coefficient
v = Drift velocity
α- η ~ 100/mm
v ~ 220 µm/ns
σt ~ 58 ps

# -I ,- "!)!
! " # $ % ! & ' ( ) * + $ , + -
# ! "
' " * $ µ - -$* ! J J M "!

Multi-pin connector
Capacitor block
MRPC glass stack
Mounting table
,- )!
Multi-strip anode
FOPIs MMRPC parameters:
90 x 4.6 cm 2 active area
1.1 & 0.5 mm 10 glass plates
8 x 220 µm gaps (fishing rope)
16 strips
1.94/0.6 mm strip/gap
~10 kV applied voltage
/
! ) > 6 % 1) 7
Stesalit support
Glass stack 8 gaps

- )!
Gas box
Gas
in/outlets
End-flange
1 MMRPC
HV-connector
Interface between MMRPC & Electronics
SAMTEC 50 multi-coaxial cable
0.8 mm pitch. In total 80 connections
(16 used).
5 MMRPCs in a Super Module (SM)
30 SMs within FOPI
N& " !"
N
ZU !"
[8N

I "

' Output ) 3 Voltage ! (mV) 5
I " !"
Gain
II2 !"O ,-2 !
400
350
300
250
200
1 !4:< 5
150
100
50
1 4= 5
0
0 2 4 6 8 10 12
")
Input
3
Voltage
!
(mV)
5
200
180
160
140
120
100
80
60
40
20
0
0 2 4

GSI+HD+I3HP
M.Ciobanu
Upper limit for FEE
electronic resolution
FOPI-threshold
FOPI-combined
"noise level"
U n ~50-60 mV
II2 ! "
GAIN=25
GAIN=100
GAIN=50
INPUT NOISE =24uV
σ )
GAIN=200
RPC RPC RPC RPC
100
100
100
100
10
10
10
10
SIGMA [ps]
THRESHOLD
-100mV
-80mV
-60mV
-40mV
-20mV
1
1
1
1
1 10 100
UINP [mV]
1 10 100
UINP [mV]
1 10 100
UINP [mV]
1 10 100
UINP [mV]
") 3 ! 5 ") 3 ! 5 ") 3 ! 5 ") 3 ! 5
Electronic gain for MRPCs in avalanche mode is between 130-180

Internal pulser
', "2I"2I "2 !
Multipin connector
Preamplifier part
QDC-out
LE
Power-stabilization
FEE4:
9.5 • 14.5 cm 2
6 layer PCB
16 ch. T/Q
Gain 160
T/Q ~ 2
0.55 W/ch
σ E

GSI-ELEX
R.Schulze.R.Hardel
K.Koch,E.Badura
', R #-S1 #
TAC ASIC
# 1 ch.
σ t

! +
Free running common stop system at 40 MHz.
Individual TAC resets 0.2-2.0 µs.
FEE + TAC/QDC-Digitizer
16 ch.
G ~ 50-250 TAC ~10 ps/ch
δf ~ 1.5 GHz Zero-suppression
time (ns)
time (ns)
yield
0
-0.2
-0.4
-0.6
-0.8
0.03
0.02
0.01
4000
2000
FOPI
timediff (ns) vs time (ns)
2004/09/30 17.22
ENTRIES 14307
0.00 13.0 0.00
0.00 0.143E+05 0.00
0.00 0.00 0.00
0 5 10 15 20 25 30
time diff. (ns)
sigma (ns) vs time (ns)
Entries
Mean
RMS
500
12.58
7.157
0
0 5 10 15 20 25 30
sigma (ns)
0
108.PROY
Entries
Mean
RMS
25000
-0.3962
0.2135E-01
45.99 / 7
Constant 5391.
Mean -0.3962
Sigma 0.2109E-01
-0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1
time diff. (ns)
P F ~ 0.56 W/ch P T ~ 0.5 W/ch Full system electronic resolution
σ E < 25 ps

! +
Free running common stop system at 40 MHz.
Individual TAC resets 0.2-2.0 µs.
FEE + TAC/QDC-Digitizer
16 ch.
G ~ 50-250 TAC ~10 ps/ch
δf ~ 1.5 GHz Zero-suppression
Electronic resolution
FEE ~ 18 ps
TAC ~ 10 ps
δt ~ 15 ps
TAC < 2 ps
+ FEE < 3 ps
+ Card 10 ps
+ Clock 10 ps
Σ δt ~ 15 ps
P F ~ 0.56 W/ch P T ~ 0.5 W/ch Full system electronic resolution
σ E < 25 ps

# -I2 II J J'
1 " \ - '$ M " +
"!= "0
0)0 ? *;
" 0σ T )
, 8! "
N "!
-$ * !

# -I2 R &-
#"
HPTDC is fed by a 40 MHz clock giving
us a basic 25 ns period (coarse count).
A PLL (Phase Locked Loop) device
inside the chip does
clock multiplication by a factor 8 (3 bits)
to 320 MHz (3.125 ns period) .
A DLL (Delay Locked Loop) done by
32 cells fed by the PLL clock acts a
5 bits hit register for each PLL clock (98
ps width LSB = 3.125 ns/32).
4 R-C delay lines divides each DLL bin
in 4 parts (R-C interpolation)

# -I " !+
σ 2 = σ 2 FEE + σ2 T0 + 2σ2 TDC + σ2 clock + σ2 clockTRM
3 *
.(=3 $$ $ 0
II )
)
&- )
-'-N )
- )
!A )
: )
-$ * !
#"
From board to board
Within board
With refined INL treatment

& ) !"

! R
Rate (Hz)
700
600
500
400
300
200
100
&!/! ,-
~ 1 Hz/cm 2
:
Darkrate 90cm-4gap RPC
0
2 3 4 5 6 7 8
Voltage (kV)
5 ! /5
3 days under high voltage to get optimal
conditions.
! R;
Rate (Hz/cm2)
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
$
0
4 5 6 7 8 9 10 11
Voltage (kV)
5 ! /5
$ 0 "& !/!
0 0 R; ! "

! R;
&!/! 3 I2
I /5;
,- I2 !"
* $?2&&+ / &
IB)A
?B 4 ==
= = /5 /5;
( &
J !T R; = R; "
+) !+ II L #S ? R; "
J ) + $

TOF (ns)
TOF (ns)
TOF norm. (ns)
10.4
10.2
10
9.8
9.6
10.4
10.2
10
9.8
9.6
1
0.5
0
-0.5
-1
$ 0" "
Slewing correction (walk)
0 200 400 600 800 1000
Charge (ch)
0 200 400 600 800 1000
Charge (ch)
0 200 400 600 800 1000
Charge (ch)
10
1
10 -1
10 2
10
1
Uncorrected TOF spectra
for all strips.
Determined walk correction
T walk < 100 ps
Corrected and normalized TOF

yield
Time Reference
Slope
lower limit
" !""2 "! +D
Differential
non−linearity
Back Bend
25 ns
(clock)
TAC
C1 (3 %) C2 (0.5 %)
TAC−yield
Principle of calibration
upper limit
TAC (ns)
Tdif Left (ns)
Tdif Left (ns)
0.1
0.075
0.05
0.025
0
-0.025
-0.05
-0.075
-0.1
0.1
0.08
0.06
0.04
0.02
0
-0.02
-0.04
-0.06
-0.08
Entries 2100
500 1000 1500 2000
’Clock cycle (bins)strip=’3
Entries 2100
500 1000 1500 2000
’Clock cycle (bins)strip=’4
TACQUILA 1
Wiggle Lookup
Tdif right (ns)
Tdif right (ns)
0.075
0.05
0.025
0
-0.025
-0.05
-0.075
-0.1
-0.125
0.05
0
-0.05
-0.1
-0.15
2004/09/28 16.10
Entries 2100
500 1000 1500 2000
’Clock cycle (bins) strip=’3
Entries 2100
500 1000 1500 2000
’Clock cycle (bins) strip=’4
TACQUIQA 2
Left Right

Time difference (ns)
0.4
0.2
0
-0.2
-0.4
*!/@0 !" !
RPC 90cm-8Gaps-16Strips
300 350 400 450 500 550 600 650 700 750 800
tof vs amp
10 3
10 2
10
1
Charge (ch)
-1 -0.75 -0.5 -0.25 0
521.PROY
0.25 0.5 0.75 1
Time difference (ns)
148.6 / 42
Constant 658.0
Mean 0.2227E-02
Sigma 0.9912E-01
10
1
10 -1
After combined corrections
for MMRPC B at 108 kV/cm
(9.5 kV).
Final resolution plot below
90 ps with a tail < 1%.
Rest tail is from non-perfect
wiggle and walk corrections
not from the detector itself.
When the counter is in
avalanche mode.

* ! ) !" ) "
! ) ,-.
( σ < 77&
* ε @ A
= % " & %
$ ! !3!!" R " !"
0 ") ! + ') !! ) " W
$ ! !/ )@! M 0 H
1.96 mm strip
0.6 mm gap

* ! ) R 0 ! .
/ & " #
!" & " #
Glass
" ! "
!" $ ) R"
HV
z
HV cathode
Y
Spacers
Multistrip anode
/ & !"
B % * & *
!" " $ %

PMT 2
PMT 3
Top View
RPC
PMT 1
) !
Front View
Trigger PMT1 & PMT2
Efficiency PMT1 & PMT2 & PMT3
Side View
PMT 2 PMT 1
PMT 3
RPC
M! π@)@

Efficiency (%)
100
80
60
40
20
Eff 250 mu
Eff 220 mu
Eff 270 mu
σ t 250 mu
σ t 220 mu
σ t 270 mu
!) R "3 ! +
" !" "+
Deuteron Beam 2 AGeV
Illuminated Area ✗ ❃❍ ✒
Total Rate 150 Hz/cm 2
FEE-Gain 77
0
0
80 85 90 95 100 105 110 115 120 125
Field (kV/cm)
200
180
160
140
120
100
80
60
40
20
σ t (ps)
- )! " " !" "+
7, 7!" 7C !) =
3
+ " ] < /5; >= H
M " ] /5; < )
" !" "+ )"
" !3!!" "+ "
I2 M ! +
!

[
[
[
* ! ! .
J )
) $D 7#
7C
7C
7C
: )
: )
: )
$ )
TS;S !B]
TS;S !B]
TS;S !B]

instr m

TJ ]
instr m
instr rms
$
1.75
1.5
2
2.75
2.5
2.25
3
3.75
3.5
3.25
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
220mu
250mu
270mu
RPC 90cm-8Gaps-16Strips
100 150 200 250 300 350 400 450 500 550 600
Charge (ch.)
220mu
250mu
270mu
- R "3 ! +
100 150 200 250 300 350 400 450 500 550 600
Charge (ch.)
TS]
- R
"3 ! @
!
)" "
Charge m
Charge rms
550
500
450
400
350
300
250
200
150
350
300
250
200
150
100
instr m
instr rms
220mu
250mu
270mu
RPC 90cm-8Gaps-16Strips
85 90 95 100 105 110 115 120
E-field (kV/cm)
220mu
250mu
270mu
85 90 95 100 105 110 115 120
E-field (kV/cm)
1.75
1.5
2
2.75
2.5
2.25
3
3.75
3.5
3.25
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
220mu
250mu
270mu
RPC 90cm-8Gaps-16Strips
85 90 95 100 105 110 115 120
E-field (kV/cm)
220mu
250mu
270mu
85 90 95 100 105 110 115 120
E-field (kV/cm)

Efficiency (%)
100
80
60
40
20
II2 !" )" "
" " O "+
MRPC 19b 90cm-8Gaps-16Strips
Single Hits
0
85 90 95 100 105 110 115 120 125 130 0
E-Field (kV/cm)
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
200
180
160
140
120
100
80
60
40
20
σ t (ps)
" !" "+
)" " I2
0! 0
" !"
* ! ! 0 I2
! "
) !"
:& 7 7
8" 77FFF

TJ ]
Instr m
Instr rms
$
2.75
2.5
3
3.5
3.25
2.25
1.75
1.5
1.25
1
2
II2 !"
)" " " R
MRPC 19b 90cm-8Gaps-16Strips
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
95 100 105 110 115 120 125
E-Field (kV/cm)
1.8
1.6
1.4
1.2
1
0.8
0.6
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
95 100 105 110 115 120 125
E-Field (kV/cm)
R 0 ! 0
! " " II2 !"
! 0 !
0 ! 0 I2
" !" "+
!(0 +0 0 " !" P

Efficiency (%)
110
100
90
80
70
60
50
40
30
20
10
! )" " "
" O "+
Efficiency
R ∼ 1 kHz / cm 2
R ∼ 0.1 kHz / cm 2
Pion Beam 2 AGeV
Illuminated Area 7 cm 2
Total Rate 100-1000 Hz/cm 2
FEE-Gain 150
0
100 105 110 115 120 125 0
E-Field (kV/cm)
200
180
160
140
120
100
80
60
40
20
σ t (ps)
Yield
10 3
10 2
10
1
MMRPC resolution
Single hits
Gap 220 µm (8)
σ t < 60 ps 0.1 kHz/cm 2
σ t < 85 ps 1.0 kHz/cm 2
ε > 98 %
Tail < 3 %
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
Time difference (ns)

1 " O& " ! "
!) R =B \ " !" ! R
I " !" ! ! "! < 5
: ! )! "! ! " ! " !"
? ') ! " ! "+! " /5;

I "+ H
Efficiency (%)
100
80
60
40
20
FEE-Gain 160
100 Hz/cm 2
,- M 3 ! )!
RPC 20b 90cm-8Gaps-16Strips 220 mu
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115
200
Proton Beam 2 AGeV
0
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115 0
Field (kV/cm)
I2 /5;
Eff.
σ t (All)
σ t (RPC)
σ t (Start)
180
160
140
120
100
80
60
40
20
σ t (ps) )
We need a start counter with
50 ps or even better.
Single hit 78 ps
Start 50 ps
RPCb + Start t < 96 ps
Start ts < 78 ps
RPC RPC < 56 ps

I "+ H
Efficiency (%)
100
80
60
40
20
,- - 3 ! )!
RPC 20c 90cm-8Gaps-16Strips 220 mu
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115
200
Proton Beam 2 AGeV
0
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115 0
Field (kV/cm)
I2 /5;
Eff.
σ t (All)
σ t (RPC)
σ t (Start)
σ t (1kHz)
180
160
140
120
100
80
60
40
20
σ t (ps) )
Stable scan with a
stable start. The start
is very important.
saturation above 105 kV/cm
At higher rates ~ 1kHz
we see a decrease of
the timing 10-15 ps.

RPC
IB) "! )
CDC
RPC
Scint+PMT
Super Module
Mini
RPC1 13a
RPC2 11a
U+Au 900 AMeV
2 MMRPCs + Mini

Single Hit
Clean
Double Hit Clean
! ! "
Both signals arrive first 101
Both signals arrive second 202
1
90 cm
1.96 mm strip
0.6 mm gap
2 1
Mixed
One signal arrives second 102
One signal arrives second 201
2

Momentum (GeV/c)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
Matched RPC 13a-90cm-6gaps-14strips CDC-MRPC hits
U+Au 900 AMeV
0
0 5 10 15 20 25 30 35
0.2
Velocity (cm/ns)
P-v plot for fast pions
Small momentum
" O "+ RPC
9
8
7
6
5
4
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
I Efficiency "+ H(%)
0.3
100
80
60
40
20
σ t < 75 ps
ε > 95 %
RPC 13a 90cm-6Gaps-14Strips
0
50 60 70 80 90 100 110 120 130 140 150 0
HTYP
Full-RPC
Mini+RPC
Fast pions
Eff.
σt-σts Eff.
σt-σts 175
150
125
100
75
50
25
Yield
30
25
20
15
10
5
0
σσ t (ps) )
U+Au 900 AMeV
-1 0 1
13a-90cm-6gaps-14strips
Entries 422
59.39 / 45
Constant 19.12
Mean -0.1338
Sigma 0.1064
Time Diff. (ns)
Yield
10
1
U+Au 900 AMeV
σ t < 75 ps
Tail < 3 %
dependence. Single Hit Case
Entries 422
59.39 / 45
Constant 19.12
Mean -0.1338
Sigma 0.1064
-1 0 1
Time Diff. (ns)

I "+ H
Efficiency (%)
100
80
60
40
20
" O "+
RPC 13a 90cm-6Gaps-14Strips
0
150 160 170 180 190 200 210 220 230 240 250 0
HTYP
Full-RPC
Mini+RPC
Fast pions
MRPC resolution
Double hits
σ t < 100 ps
ε > 85 %
Eff.
σt-σts Eff.
σt-σts Double Hit Case
175
150
125
100
75
50
25
σ )
σ t (ps)
" 5;
5 + ;"
P-v plot with MRPC
Protons
Kaons
1GeV/c 2
Pions

E.Cordier
Pions
M!/ "
Protons
Pions
Protons
Mass cuted (GeV/c 2 )

IB " )

!)!+ -I J
Barrel: 30 RPCs in 2 layers
• Length: 2 m
• Width: 150 mm
• Thickness: 10 mm
positive tracks
+ negative tracks

Beta
e
!)
+8.9 GeV/c 0.05 λ Be target – pad ring 5 (average σ t )
Momentum (GeV/c)
p
positive tracks
e
p
negative tracks
Momentum (GeV/c)

electrons
,! K - L#
Kaons
pions
protons
- $ ' "1(23
! !"MJ
* !"" MJ
-I

# -I ,-) !"
-* !
& !R ! ,- :
96 readout pads
per strip
120 cm

#&I$ ,-) !"
Consistent with
empty space
between cells
Gas admixture: 98.5% C 2 H 2 F 4 + 1% SF 6 + 0.5 iso-C 4 H 10
& "R! R ,- :

$ !+@- " "O' /

Efficiency (%)
100
80
60
40
20
Eff 250 mu
Eff 220 mu
Eff 270 mu
σ t 250 mu
σ t 220 mu
σ t 270 mu
- " " "
!) R@ II2 !"!" !
Deuteron Beam 2 AGeV
Illuminated Area ✗ ❃❍ ✒
Total Rate 150 Hz/cm 2
FEE-Gain 77
0
80 85 90 95
0
100 105 110 115 120 125
Field (kV/cm)
200
180
160
140
120
100
MMRPC resolution
Single hits
σ t < 50 ps FEE (200)
σ t < 60 ps FEE (150)
σ t < 75 ps FEE (77)
ε > 99 %
80
60
40
20
σ t (ps)
Efficiency (%)
100
80
60
40
20
MRPC 19b 90cm-8Gaps-16Strips
Single Hits
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
0
85 90 95 100 105 110 115 120 125 130 0
E-Field (kV/cm)
200
180
160
140
120
100
80
60
40
20
σ t (ps)
Efficiency (%)
100
80
60
40
20
1"3 ! !3
" !" "+@
"+ )" " "I2
RPC 20c 90cm-8Gaps-16Strips 220 mu
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115
200
Proton Beam 2 AGeV
0
90 92.5 95 97.5 100 102.5 105 107.5 110 112.5 115 0
Field (kV/cm)
Eff.
σ t (All)
σ t (RPC)
σ t (Start)
σ t (1kHz)
180
160
140
120
100
80
60
40
20
σ t (ps)

σ t (RPC) (ps)
140
120
100
80
60
σ t (RPC) = σ t - σ ts
σ ts =120 ps
- " " "
40
20
MRPC > 0
MRPC =1
MRPC =2 (P1 or P2)
Al-Beam 1.9 AGeV
Illuminated Area 414 cm
0
102 104 106 108 110 112 114 116 118
E-Field (kV/cm)
2
Total Rate 4-5 kHz/MMRPC
Coincidence Rate 10-15 Hz/cm 2
FEE-Gain 77
MMRPC resolution
Double hits
σ t < 100 ps
ε > 85 %
Efficiency (%)
100
80
60
40
20
RPC 13a 90cm-6Gaps-14Strips
0
150 160 170 180 190 200 210 220 230 240 250 0
HTYP
Full-RPC
Mini+RPC
:
Eff.
σt-σts Eff.
σt-σts 175
150
125
100
75
50
25
σ t (ps)

instr m
instr rms
1.75
1.5
2
2.75
2.5
2.25
3
3.75
3.5
3.25
1.6
1.5
1.4
1.3
1.2
1.1
1
0.9
220mu
250mu
270mu
- " " "
RPC 90cm-8Gaps-16Strips
100 150 200 250 300 350 400 450 500 550 600
Charge (ch.)
220mu
250mu
270mu
100 150 200 250 300 350 400 450 500 550 600
Charge (ch.)
R
- R )"
"+ " !
* " \ !"
II2 !"
Instr m
Instr rms
2.75
2.5
3
3.5
3.25
2.25
1.75
1.5
1.25
1
2
MRPC 19b 90cm-8Gaps-16Strips
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
95 100 105 110 115 120 125
E-Field (kV/cm)
1.8
1.6
1.4
1.2
1
0.8
0.6
FEE-Gain 220
FEE-Gain 160
FEE-Gain 130
FEE-Gain 77
95 100 105 110 115 120 125
E-Field (kV/cm)
& !" I@ 3
I " !"

M!/ " O "
$"
&
E.Cordier

- " " " ! "
330 ps
40 ps
60 ps
25 ps
Yield
4500
4000
3500
3000
2500
2000
1500
1000
500
ID
Entries
Mean
RMS
100
27948
0.4971
3.031
505.0 / 42
Constant 3974.
Mean 0.5036
Sigma 2.755
0
-25 -20 -15 -10 -5 0 5 10 15 20 25
dt rate 10e6
Time diff. (ch)
#) !" ! ! !
" + ! ! " 0
! ts < 7& !- ! ! R
total = 452 + 352 + ts 2 ps
total = 75 ps ts = 50 ps

" ! " ! 76 H " ! "
V 777 #
!)) ! "
,- -M
TOF
' 0! ! ! :^

Rate (dN/cm 2 /s)
10 5
10 4
10 3
10 2
10
1
URQMD AU+AU 25AGeV, MinB
!" ! + -M
dist=1500cm (TOF)
2000Hz
0 10 20 30 40 50
Θ (deg)
Concepts:
Different detectors types
in low and the high rate
environment.
Low rate 2 kHz
Pad anode
Single cells
Problem:
Different counters may need
different electronics.

,!) " " ,-
Doctoral Thesis, C. Lippmann, May 2003 (CERN, University of Frankfurt)
NIMA 500 (2003) 144-162, W. Riegler, C. Lippmann, R. Veenhof
NIMA 491 (2002) 258-271, W. Riegler
NIMA 481 (2002) 130-143, W. Riegler, D. Burgarth
Proceedings of IEEE NSS/MIC (2002), C. Lippmann, W. Riegler
NIMA 489 (2002) 439-443, CERN-OPEN-2001-074, T. Heubrandtner, B. Schnizer, C. Lippmann, W. Riegler
G. Carboni et al. NIM A 498(2003)135 [2 mm RPC]
G. Aielli et al. NIM A 508(2001)6, RPC 2001 [2 mm RPC]
P. Colrain et al. NIM A 456(2000)62
A. Mangiarotti et al. NIM A 533(2004)16 RPC 2003
D.Gozalez Diaz et al. Nucl. Phy. B (Proc.Suppl.) 158 (2006) 111-117
V.Ammosov et al. Nucl. Phy. B (Proc.Suppl.) 158 (2006) 56-59
A.Schüttauf et al. Nucl. Phy. B (Proc.Suppl.) 158 (2006) 52-53
A.Schüttauf et al. NIM A 553 (2004) 65-68
H. Alvarez-Pol et al. NIM A 535 (2004)277
M.C.S. Williams et al. NIM A 478 (2002) 183-186
M.Petrovici et al. NIM A 508 (2000) 75-78