1. Mauro Raggi Status report on the new charged hodoscope for P326 Mauro Raggi for the HODO working group Perugia – Firenze 07/09/2005

2. 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

3. Mauro Raggi The ALICE Multigap Resistive Plate Chambers (MRPC)

4. Mauro Raggi ALICE 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 cm 2 area for each module 7x120 cm 2 active area for each module Greater number of gaps Lower HV (+6.5 kV, -6.5 kV) Signal amplitude greater of a factor 2

5. Mauro Raggi The ALICE PCB layout

6. 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). On each front end card 3 NINO chip are mounted so the card can handle 24 ch. The NINO ASIC bonded to the PCB

7. Mauro Raggi MRPC performance Efficiency > 99% Time resol. < 50 ps Test performed with the ALICE TOF rate 50 Hz

8. 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

9. Mauro Raggi Ageing test at GIF Irradiation with 7∙10 9 particles/cm 2 The performances seem to remain stable in time The total amount of irradiated charge is equivalent to only 140 days of P326 run:

10. Mauro Raggi The new P326 Charged Hodoscope

11. Mauro Raggi Fast Charged Hodo requiremets 1.Time resolution better than 100 ps 2.Operation rate > 2 kHz/cm 2 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

12. Mauro Raggi Possible hodo layout 240x240 cm 2 detector 2 or 3 planes to avoid dead space 4 quadrants: 120x120 cm 2 ~ 960 pads per quadrant ~ 20 slabs 6x120 cm 2 sensible area ≤ 48 pads per slab Front end electronics The final geometry and granularity will be fixed using MC simulation 120 cm

13. Mauro Raggi Possible slab configuration Beam Plane 1 Plane 2 Beam Plane 1 Plane 2 Plane 3 Solution ASolution B Modules160180 Front end Chips9601080 Front end cards320360 Solution ASolution B 48 ch per Moudule76808640 24 ch per module38404320 Readout TDC?? Solution ASolution B

14. Mauro Raggi 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

15. Mauro Raggi The problem of signal collection In the ALICE configuration you do not have any reflection due to very short trasmission line from pads to connectorsP326 ALICE 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

16. Mauro Raggi New detector for P326 5 x 400  m glasses PCB anodico Layout of a single stack module 6 Gaps 250  m PCB catodico +10-13 KV 0 flottante Ground layer Strip line layer Pad layer Empty layer Empty layer Pad layer Strip line layer Ground layer 550  m glass X 0 (mm) (1 Plane)% X 0 (3 Planes)% X 0 Glass127.03.1 mm2.459.3 mm7.3 PCB (FR4)174.03.4 mm1.9510.2 mm5.85 4.413.2

17. Mauro Raggi PCB Layout Pads plane 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 cm 2 48 stripline of 0.4 mm width with a distance of 1 mm to avoid crosstalk

18. Mauro Raggi The 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 cm20 cm30 cm 48 pads =2.4*3.4 cm 2 connected to the readout 48 pads =2.4*3.4 cm 2 not connected to the readout 60 cm

19. Mauro Raggi The test facility MRPC-1MRPC-2MRPC-3 Interface board FE electronic boards 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

20. 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.