Mauro Raggi

Status report on the new charged Status report on the new charged hodoscope for P326hodoscope for P326

Mauro Raggi

for the HODO working group Perugia – Firenze

07/09/2005

Mauro Raggi

Outline 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 The ALICE Multigap Resistive Plate Chambers (MRPC)Chambers (MRPC)

Mauro Raggi

ALICE detector layoutALICE detector layout

2 anode and 1 chatode PCB with picup pads

5+5 250 m 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

13x120 cm2 area for each module

7x120 cm2 active area for each module

Greater number of gaps

Lower HV (+6.5 kV, -6.5 kV)

Signal amplitude greater of a factor 2

Mauro Raggi

The ALICE PCB layoutThe ALICE PCB layout

Mauro Raggi

FrontEnd electronicFrontEnd electronicALICE 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).

On each front end card 3 NINO chip are mounted so the card can

handle 24 ch.

The NINO ASIC

bonded to the PCB

Mauro Raggi

MRPC performanceMRPC performance

Efficiency > 99%Time resol. < 50 ps

Test performed with the ALICE TOF rate 50 Hz

Mauro Raggi

Rate tests at GIFRate 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 GIFAgeing 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:

)(2

9

3261

86400*/

107daysRUNP

cycledutycmrate

Mauro Raggi

The new P326 Charged HodoscopeThe new P326 Charged Hodoscope

Mauro Raggi

Fast Charged Hodo requiremetsFast 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 layoutPossible hodo layout

240x240 cm2 detector

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 electronicsThe final geometry and granularity will be fixed using MC simulation

120 cm

120 cm

Mauro Raggi

Possible slab configurationPossible slab configuration

Beam

Plan

e 1P

lane 1

Plan

e 2P

lane 2

Beam

Plan

e 1P

lane 2

Plan

e 3Solution A Solution B

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 ?? ??

Solution A Solution B

Mauro Raggi

The new PCB for P326The 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 The problem of signal collection

In the ALICE configuration you do not have any reflection due to very short trasmission line from pads to connectors

P326P326ALICEALICE

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 P326New detector for P326

5 x 400m glasses

PCB anodico

Layout of a single stack module

6 Gaps 250m

PCB catodico

+10-13 KV

0 flottante

Ground layerStrip line layerPad layerEmpty layer

Empty layerPad layerStrip line layerGround layer

550m glass

550m glass

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 13.2

Mauro Raggi

PCB LayoutPCB Layout

Pads plane

0.5

mm

0.5

mm

0.7

mm

1.7

mm

Ground plane

Strip line plane

Empty plane

0.4 mm

1 mm

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

Mauro Raggi

The first prototypeThe first prototype

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

We will use exaclty the same geometry of the alice PCB but introducing strip to transport the signal and the ground plane

50 pin connector

Layout of PCB prototype with 48 channels

10 cm 20 cm 30 cm

48 pads =2.4*3.4 cm2 connected to the readout

48 pads =2.4*3.4 cm2 not connected to the readout

60 cm

Mauro Raggi

The test facilityThe test facility

MR

PC

-1

MR

PC

-2

MR

PC

-3

Interfaceboard

FE

electronicboards

Gas in

HV

48 readout channels 2 flat 50 pin connectors 2 front end boards each MRPC 6 front end “Nino” chips

For each MRPC

144 readout channels 6 flat 50 pin connectors 6 front end boards each MRPC 18 front end “Nino” chips

All test facility

In order to test the module performance we will contruct a 3 modules test facility

Mauro Raggi

ConclusionConclusion

A first prototipe for a hodo module has been developedThe production of the PCB starts in september First prototype assembly foreseen in october Cosmic ray test will be hopefully done within 2005Test of efficiency and time resolution at high rate are

mandatory to validate detector performance in the P326 environment: test with NA48 facility in 2006.