CEPC 数字强子量能器读出电子学预研进展 张俊斌 中国科学技术大学 核探测与核电子学国家重点实验室 2016/8/22

OUTLINE BACKGROUND CEPC-Detector CEPC-HCAL DHCAL SDHCAL USTC-SDHCAL MICROROC Detector plane overview Phase I: prototype readout scheme Microroc & Hardroc2b test board SDHCAL DIF board Active Sensor Array board Status

CEPC(Circular Electron Positron Collider) Beam Energy: 120GeV Luminosity: 2× 10 34 𝑐𝑚 −2 𝑠 −1 Circumference: 53.6km Higgs factory

JET ENERGY MEASUREMENT Classic Calorimeter 𝐸 𝐽𝑒𝑡 = 𝐸 𝑒𝑐𝑎𝑙 + 𝐸 ℎ𝑐𝑎𝑙 Approximately 72% of the jet energy is measured with the precision of the combined ECAL and HCAL for hadrons and the jet energy resolution is limited by the relatively poor hadronic energy resolution.

Particle flow algorithm & calorimetry PFA Calorimeter Particle flow algorithm Charged particles –tracker Photons – electromagnetic calorimeter Neutral hadrons – hadronic calorimeter High- granular ECAL: separate energy deposits from photoelectrons and hadrons HCAL: separate energy deposits from charged and neutral hadrons

CEPC-DETector The CEPC calorimeters, including the high granularity electromagnetic calorimeter (ECAL) and the hadron calorimeter (HCAL), are designed for precise energy measurements of electrons, photons, taus and hadronic jets. The basic resolution requirements for the ECAL and HCAL are about 16%/ 𝐸(𝐺𝑒𝑉) and 50%/ 𝐸(𝐺𝑒𝑉) . To achieve these, a Particle Algorithm oriented calorimetry system is being considered as the baseline design.

CEPC-HCAL AHCAL DHCAL HCAL SDHCAL A high-granularity HCAL plays an essential role in CEPC. It allows separation of energy deposits from charged and neutral hadrons. The measurement accuracy of the neutral hadrons is the leading contribution to the jet energy resolution for jets with energy up to 100GeV. sampling calorimeter (steel + Gaseous detector) AHCAL Scintillator + SiPM + SPIROC(ASIC), 8148channels,1m3 HCAL DHCAL GEM/RPC/Micromegas + DCAL(ASIC), 4× 10 5 chn/m3 A hadron calorimeter with only one threshold readout is called a Digital Hadron Calorimeter (DHCAL). SDHCAL GEM/RPC/Micromegas + HARDROC(ASIC), 4× 10 5 chn/m3 A more general calorimeter with multi-threshold readout (e.g. 3 thresholds) is therefore also considered, a so-called Semi-Digital Hadron Calorimeter (SDHCAL).

DHCAL Architectural of the DHCAL The first 1 m3 RPC-based DHCAL prototype built at Argonne National Laboratory(ANL) in 2010 Architectural of the DHCAL 54 layers with 1m2 area per layer. Each layer has 2cm iron absorber. The first 38 layers have a uniform thickness of absorber, while the last 16 layers increase of the absorber thickness from 2cm to 10cm, used as tail catcher for very high energy particles The prototype has about half a million channels

DHCAL-readout system Multi-muon tracks passing through

SDHCAL An SDHCAL prototype was built by IPNL. comprising 48 active layers Each layer is made of 1 m2 GRPC, which readout through 9216 pads of 1cm2 each. An 80GeV pion event display with red indicating pads fired at the highest threshold, blue those at the middle threshold, and green those at the lowest threshold. The use of the three thresholds has a very good impact on the energy resolution at energies higher than 40GeV. Excellent linearity and energy resolution up to 80GeV were obtained during the two periods of beam exposure at CERN.

SDHCAL-readout system

USTC-SDHCAL PADs readout Approximatively, 95% Energy included longitudinal length: L(95%)=[0.56*ln(E/GeV)+2.33] λI E=100GeV, L(95%)=4.9 λI =82.2cm(Fe)=48.7cm(W)=75.1cm(Cu) The energy resolution of HCAL will be improved by using more sampling layers, but it won’t work any more when d<2cm (for Fe) . 95% Energy included transverse radius: ~30cm for 50GeV π±, 99% hits in 70cm× 70cm. PADs readout 70 cm

microroc Multi-thresholds channels Dynamic range Hardroc2 64 10fC~10pC Hardroc3 10fC~50pC Microroc 1fC~500fC MICROROC is dedicated chip for GEM/MICROMEGAS. MICROROC (pin pin compatible with HR2b) is based on HR2b same back-end, same readout format, same pinout, only the preamplifier is changing.

Microroc Gain =4 1fc~500fC Gain =1 The noise of the PAC followed by the HG shaper (tp=200 ns) have been simulated and found equal to 0.25 fC which allows to set the threshold of the discriminator that follow the HG shaper to a very low value such as 2fC.

Detector plane overview 1m2 detector plane: 4 ASUs Detector plane characteristics: PCB with buried blind vias. 36 MICROROC chips / ASU 9216 channels / plane 1.2mm max thickness (PCB) All components on top < 1.4mm ASU-ASU Connector DIF Detector InterFace ASU Active Sensor Unit

Ustc SDHCAL readout for future

ECAL&HCAL readout for future

Phase I : prototype

Microroc & Hardroc2b test board

SDHCAL DIF board

Active Sensor Array board Active area:30𝑐𝑚×30𝑐𝑚 900 pads in total (4 pads unused) 14 connectors Layout Cross Section: GND--SIG1--GND--SIG2--GND--SIG3--GND--PADs (Top --------------------------------------------------bottom)

Kapton cables Test board DIF Test board ASA board

Status status Test board √ DIF board Active Sensor Array board Test board DIF (Kapton) ASA board Test board(Kapton) FPGA firmware just started Application software

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