Transcript Analisi fondo p+p0p0 e W - Istituto Nazionale di Fisica

Status report on the new charged
hodoscope for P326
Mauro Raggi
for the HODO working group
Perugia – Firenze
07/09/2005
Mauro Raggi
Outline
 The ALICE MRPC
– Detector layout
– Performance: time resolution, efficiency, rate, and ageing
 MRPC in the P326 Charged hodoscope
– Possible design for charged hodo
– Channels and readout
– The signal collection and the new PCB layout
– Prototype development status
 Conclusion
Mauro Raggi
The ALICE Multigap Resistive Plate
Chambers (MRPC)
Mauro Raggi
ALICE detector layout
 13x120 cm2 area for each module
 7x120 cm2 active area for each module
 2 anode and 1 chatode PCB with picup pads
 5+5 250 mm gaps filled with gas mixture
 1 cm honeycombs panel for mechanical stability
 96 pads per module readout with 32 flat cable
 Differential signal send to interface card
 Greater number of gaps
 Lower HV (+6.5 kV, -6.5 kV)
 Signal amplitude greater of a factor 2
Mauro Raggi
The ALICE PCB layout
Mauro Raggi
FrontEnd electronic
ALICE has developed for this porpouse, fast (1ns peaking time)
front-end amplifier/discriminator (NINO). Each NINO can handle 8
channels.
The input is low impedance (40-75 Ω) differential, and the output
standard is an open-collector LVDS (Low Voltage Differential
Signal).
NINO can respond to another signal immediately (few ns) after the
end of a previous signal (almost no dead time).
The NINO ASIC
bonded to the PCB
On each front end card 3 NINO chip are mounted so the card can
handle 24 ch.
Mauro Raggi
MRPC performance
Efficiency > 99%
Time resol. < 50 ps
Test performed with the
ALICE TOF rate 50 Hz
Mauro Raggi
Rate tests at GIF
 The MRPC were tested for efficiency up to a rate
of 1.6 kHz
 The performance seem to be stable only using an
effective voltage of 11.4 kV
 The MRPC were tested for time resolution up to
a rate of 1.6 kHz
 The time resolution seem to decrease a little bit
 The resolution at 1.6 kHz is well above 100 ps
 This performance are very suitable for P326
 New high rate test are mandatory to validate
performance up to 5 kHz
Mauro Raggi
Ageing test at GIF
Irradiation with 7∙109 particles/cm2
The performances seem to remain stable in
time
 The total amount of irradiated charge is
equivalent to only 140 days of P326 run:
7  109
1

 P326RUN ( days )
2
rate / cm * 86400 duty  cycle
Mauro Raggi
The new P326 Charged Hodoscope
Mauro Raggi
Fast Charged Hodo requiremets
1. Time resolution better than 100 ps
2. Operation rate > 2 kHz/cm2 beam region
3. “Q1” Efficiency >99% with low “Q2”
contamination
4. Radiation hardeness to resist to 240 days of run
5. No dead space
6. Low material budget in front of LKR
Mauro Raggi
Possible hodo layout
120 cm
240x240 cm2 detector
120 cm
2 or 3 planes to avoid dead space
4 quadrants: 120x120 cm2
~ 960 pads per quadrant
~ 20 slabs 6x120 cm2 sensible
area
≤ 48 pads per slab
Front end electronics
The final geometry and granularity will be
fixed using MC simulation
Mauro Raggi
Possible slab configuration
Solution A
Modules
160
180
Front end Chips
960
1080
Front end cards
320
360
Solution A
Solution B
48 ch per Moudule
7680
8640
24 ch per module
3840
4320
??
??
Readout TDC
Mauro Raggi
Solution B
Beam
Solution B
Plane 1
Plane 2
Plane 3
Beam
Plane 1
Plane 2
Solution A
The new PCB for P326
 The PCB design used by ALICE is not suitable for P326:
– The connectors on each side introduce too much dead space
between two modules
– It’is very difficult to bring signals out of the detector using
ALICE configuration
– The material budget would not be uniform due to connectors
and cables
 A new layout of the PCB has to be designed
– Strip line to transport the signal to one side of the detector
– Connectors only at the end of each module
Mauro Raggi
The problem of signal collection
ALICE
P326
In the ALICE configuration you do not
have any reflection due to very short
trasmission line from pads to connectors
In P326 the longer transimission line is up
to 120cm. This may introduce reflections of
the signal if the line impedence is not
controlled.
The impedence of the strip line can be
controlled using a ground plane in the PCB
Mauro Raggi
New detector for P326
Layout of a single stack module
PCB catodico
Ground layer
Strip line layer
Pad layer
Empty layer
+10-13 KV
550mm glass
6 Gaps
250mm
5 x 400mm glasses
550mm glass
0 flottante
Empty layer
Pad layer
Strip line layer
Ground layer
PCB anodico
X0(mm)
(1 Plane)
% X0
(3 Planes)
% X0
Glass
127.0
3.1 mm
2.45
9.3 mm
7.3
PCB (FR4)
174.0
3.4 mm
1.95
10.2 mm
5.85
4.4
Mauro Raggi
13.2
PCB Layout
0.7 mm
Strip line plane
0.5
mm
1.7 mm
0.5
mm
Ground plane
Pads plane
Empty plane
Total thickness 1.7 mm
 Empty plane thickness fixed by high HV ≤ 15 kV
 Ground plane thickness = empty plane one due to symmetry
Pads dimension 2.4x3.4 cm2
48 stripline of 0.4 mm width with a distance of 1 mm to avoid crosstalk
1 mm
0.4 mm
Mauro Raggi
The first prototype
We will use exaclty the same geometry of the alice PCB but introducing strip to
transport the signal and the ground plane
Layout of PCB prototype with 48 channels
10 cm
20 cm
30 cm
60 cm
48 pads =2.4*3.4 cm2 connected to the readout
48 pads =2.4*3.4 cm2 not connected to the readout
50 pin connector
We want to check if the signal transportation through strips to the final
connector will actually work
What is the effect of the ground plane in the efficiency and timing performance
of the detector
Mauro Raggi
The test facility
HV
FE electronic
boards
Interface
board
Gas in
For each MRPC
In order to test the module
performance we will contruct a 3
modules test facility
48 readout channels
2 flat 50 pin connectors
2 front end boards each MRPC
6 front end “Nino” chips
MRPC-3
MRPC-2
MRPC-1
All test facility
144 readout channels
6 flat 50 pin connectors
6 front end boards each MRPC
18 front end “Nino” chips
Mauro Raggi
Conclusion
 A first prototipe for a hodo module has been developed
 The production of the PCB starts in september
 First prototype assembly foreseen in october
 Cosmic ray test will be hopefully done within 2005
 Test of efficiency and time resolution at high rate are
mandatory to validate detector performance in the P326
environment: test with NA48 facility in 2006.
Mauro Raggi