1 Construction of technological semi-digital hadronic calorimeter using GRPC Imad Laktineh CIEMAT, Gent, IPNL, LAL, LAPP, LLN, LLR, LPC, Protvino, Tsinghua, Tunis Calor2010-Beijing

2 Advantages of a semi-digital gaseous HCAL Gaseous detectors : 1- Homogeneity 2- Granularity 3- Cost-effectiveness Power-pulsed semi-digital readout : At high energy the shower core is very dense  simple binary readout will suffer saturation  semi-digital readout (2-bit) can improve the energy resolution. GRPC 1 cm 2 pad Avalanches

3 Barrel Endcap The mechanical structure proposed for the SDHCAL-ILD : Self-supporting Eliminates projective cracks Minimizes barrel / endcap separation (services leaving from the outer radius) Module Semi-Digital Hadronic Calorimeter for ILD Services

4 Beam AIMS: 1-Build a prototype as close as possible to the ILC module thin detector, reduced dead zones, pulsed electronics, services…. 2-Study the hadronic showers and discriminate models 40 layers = 40 (detector (6 mm)+ absorber(2 cm)) Auto-supporting structure, services from one side A technological semi-digital hadronic calorimeter project : Beam DIF gas H. V Technological semi-digital hadronic calorimeter project 40 units:  2 cm absorber+6mm sensitive medium  1 cm 2 transversal granularity Minimized dead zone Minimized thickness Power pulsing

5 Mechanical Structure Absorbers will be assembled together using lateral spacers fixed to the absorbers through bolts. Detailed study has been made to evaluate the robustness of this structure in different positions

6 Cassette structure Cassette forms the elementary unit. Itincludes the GRPC detector and associated electronics. It allows to fix the electronics on one of the cassette wall. Walls are part of the absorber DIF detector electronics

7 Final total thickness 11 mm aperture 12.5 mm Successful insertion from above

8 Cross-section of GRPCs PCB support (FR4 or polycarbonate) PCB (1.2mm) Mylar layer (50μ) Readout ASIC (Hardroc2, 1.4mm) PCB interconnect Readout pads (1cm x 1cm) Mylar (175μ) Glass fiber frame (1.2mm) Cathode glass (1.1mm) + resistive coating Anode glass (0.7mm) + resistive coating Ceramic ball spacer (1.2mm) Total thickness including embedded electronics: 5.825mm Gas gap

9 Homogeneity : within the same detector but also from one detector to another  Glass : ok  Mylar : ok  Painting : This is an issue but using the silk screen painting technique this is ok  Gas distribution : new schemes  uniform distribution  Distance between the two plates : This is vey Important (E=ΔV/d) Deformation < 40 µ

10 homogenous painting for large surface: Graphite: (400 K Ω/□) Standard but rather high multiplicity (>1.6 pads/mip at 7.4 kV), no HV connection problem Licron : (> 20 M Ω/□) : Spray, good multiplicity, HV long-term connection problems ( HV lost after few months) Statguard: (few M Ω/ □) : Liquid painting, stable, no HV connection problem observed so far but homogeneity is not excellent when painted with a roll Colloidal graphite : (few M Ω/ □) same advantages as for the statguard but more suited for silk screen printing. The more resistive the painting the smaller the multiplicity Resistive coating

11 Silk Screen Printing :  Provides homogenous and well controlled coating.  Used in OPERA GRPCs.  Simple tools are needed (reduced cost) R MAX /R MIN < 2 over 1 m 2 surface

12 Gas circulation system was conceived and checked with sophisticated simulation tools with the aim to reduce gas consumption and to guarantee a well distributed gas Speed : Few mm/s When diffusion is included  Homogeneity is even better

13 Aging studies: We have 2 GRPCs (standard 1m 2, semi-conductive small GRPC) in the GIF facility (10 3 Hz/cm 2 ) since October Correlation between gain, temperature, pressure and humidity (open loop) is currently under study in order to deduce the irradiation effects. After adding bubbler Without a bubbler humidity current

14 ASICs : HARDROC1(2) 64 channels, memory : 128 evts 2(3) thresholds Range: 10 fC-10pC Gain correction  uniformity Power-pulsed  consumption< 10µW/ch (0.5% ILC duty cycle), X-talk < 2% Electronics for GRPC-SDHCAL 30 fC 10 fC Piedestal 4.7 mm 4.3mm DAC output (Vth) Trigger 25 µs LAL

15 DHCAL Mechanical support Large electronics boards with the required quality (8-layer, buried vias..) are not currently available so smaller boards need to be assembled PCB dimensions and PCB connections were optimized

ASICs= 9216 channels/1m 2 1 pad= 1cm 2, interpad distance =.5 mm Connector board to DIF: Kapton flex Connector board to board: Kapton flex

17 Trig_ext (Lemo1) Enable Acq Enable PP Vth2 Power On Power Off 50 µs Enable PP Vref -G.R.I Power pulsing was successfully tested on a 24-ASIC electronic board The board associated to a GRPC will be tested in a 3-Tesla B field in June (SPS-H2) Electronics: Power Pulsing on large scale

18 A robot will be used to test the ASICs Max test time : 10 minutes/ASIC using Labview-based application Electonics: ASICs stand test

19 Acquisition system An acquisition system developed within CALICE collaboration will be used The different elements were designed and prototypes produced They are being now extensively tested.

20 Services: High Voltage Cockcroft-Walton system is selected as the baseline for the technological prototype. It satisfies safety requirement and ILD volume limitation. A module was developed in collaboration with ISEG Characteristics: 0-5 V  0-10 kV I <10µA I,V monitoring Residual noise 50 mV A card to control/monitor the voltage/current of the 40 modules independently was conceived and being produced HT µC V set I set I mon V mon V ref SPI Enable ID ADCDAC CAN Transceiver

21 Services: Gas distribution system To feed 40 GRPCs without contamination risks Dynamic precision < 2%

22 Services: Cooling: Thermal Study Model  100 mW chips (no power pulsing)  No cooling, thermal dissipation by convection only, T(hall) = 20°c  3 absorbers et 2 detecteurs (1/4 of 1m 2 +symmetry)  Cubic grid Codes  Catia V5  EFD flomerics Results: ΔT< 5°  no need for cooling

23 Simulation and performance study Simulation should be as realistic as possible : 1- Including dead zones and edge effects 2- Obtaining the same efficiency and multiplicity as for data 3- Developing new algorithms to improve on energy resolution and PFA: Neural Network, Hough Transform, Minimum Spanning Tree…..

24 Use Polya function to simulate the produced charge on the anode. Fix the Polya function parameters and total normalization factor from data. Charge distribution Comparison data/simulation Data MC MIP charge spectrum Efficiency%threshold Ongoing study

25 Pad Multiplicity 1.0cm S1 S2 S3 d Data: Simulation: pm at different threshold when d=0.11 Ongoing study

26 To determine the energy a Neural Network can be very helpful INPUTS : Number of pads with 1st,2d and 3d threshold (N 1,N 2,N 3 ) Additional inputs taking into account the shower shape and its extension as well as shower density distribution are being studied Energy resolution E reconst σ/E E( GeV) Ongoing study

27 Tracking, clustering algorithms Minimum Spanning Tree :  Powerful tool to connect clusters into appropriate branches.  Useful to separate electromagnetic from hadronic contribution 10 GeV Hough Transform : find MIP inside the hadronic shower and use them to calibrate/control the detector Ongoing study

28 Conclusion and perspectives A lot of progress towards a technological prototype was achieved during 3 years of R&D Production of 2 units similar to those expected for future ILD SDHCAL is completed. Test beam next week will provide the final validation. Prototype construction is expected to be completed before the end of the year Standard GRPCs can be easily replaced by other detectors : Bakelite, MGRPCs, High-Rate GRPCs in order to find the best candidate

29 Backup

30 Resistivity control using SSP technique

31 Cosmic Test Bench in LLN A test stand under preparation in Louvain-la-Neuve laboratory using (scintillators+fibers+PMT) Will be used to test the detectors

32 Single particle Jet Gas(GRPC) Single particle dE/dX charge scintillator

33 Time in seconds for gas to reach a given point in the chamber after entering the volume; diffusion included

34 Cassette design