1. LABORATORI NAZIONALI DI FRASCATI
The µ-RWELL in RD_FA
G. Bencivenni1, G. Cibinetto2, P.Giacomelli3
1. LNF – INFN , 2. INFN – Ferrara, 3. INFN – Bologna

2. The detector architecture
Copper top layer (5µm)
DLC layer (<0.1 µm)
R ̴100 MΩ/□
Rigid PCB readout
electrode
Well pitch: 140 µm
Well diameter: µm
Kapton thickness: 50 µm 1 2 3
µ-RWELL PCB
Drift cathode PCB
G. Bencivenni et al., 2015_JINST_10_P02008
The µ-RWELL is composed of only two elements:
the µ-RWELL_PCB and the cathode
The µ-RWELL_PCB, the core of the detector, is realized by coupling:
a “suitable patterned kapton foil” as “amplification stage”
a “resistive layer” for discharge suppression & current evacuation:
“Single resistive layer” (LR) <100 kHz/cm2: single resistive layer  surface resistivity ~100 MΩ/☐ (CMS-phase2 upgrade; SHIP)
“Double resistive layer” (HR) > 1 MHz/cm2: more sophisticated resistive scheme must be implemented (MPDG_NEXT- LNF) suitable for LHCb-Muon upgrade
a standard readout PCB
(*) DLC = Diamond Like Carbon
High mechanical & chemical resistant material 2

3. 2017 R&D Program
Technology Transfer to ELTOS for single-resistive layer (large area – collaboration w/CMS) PCB-RWELL manufacturing: in progress (final kapton etching still at CERN)
Technology Transfer to Techtra for the etching of the amplification-stage (kapton etching): in progress
Ageing GIF++ (in collaboration w/CMS) of large area single-layer RWELL + small area double-layer (v1.0) RWELL: in progress (until end 2017)
Construction of NEW prototypes based on double-resistive layer layout with pad readout: 10x10 cm2 with pad size of 0.6x0.8 cm2
Test H4-SPS (5 – 19 Jul) : efficiency, cluster-size, rate capability (up to ~1 MHz/cm2)
Test PSI (4 –18 Dec) with high intensity hadron beam in current mode (waiting for funding by Commissione I – 10 k€):
- rate capability with a particle flux up to 20 MHz/cm2
- discharge probability
- integrating a charge equivalent to several years of HL-LHC
Presentato progetto MAECI: “Design, Industrialization and Production of an innovative Micro Pattern Gas Detector (MPGD) based on the micro-RWELL technology“ 3

4. 2018 R&D program
The main goal of 2018: integrate the skills of both ELTOS/TECHTRA Companies to reach a fully operational single-resistive-layer (SRL) detector completely manufactured outside of CERN as a product on the shelf of the two Companies. To fulfil this milestone an intense fine tuning of all manufacturing steps must be scheduled, requiring several iterations and strict interactions with both Companies.
The 2018 program will develop with the following scheme and task sharing:
SRL micro-RWELL prototypes design with strips and pad readout: LNF
optimization and industrialization of the production processes (for SRL scheme) at ELTOS/TECHTRA: LNF
prototype construction and QC/QA with X-rays (gain, uniformity, rate capability): LNF
integration of the front-end electronics and DAQ: INFN-Fe
DAQ and reconstruction software INFN-Fe
prototype characterization with pion/muon beam
at H4/H8-SPS-CERN (efficiency, spatial resolution): INFN-Bo, INFN-Fe, LNF

5. Anagrafica LNF – Bologna - Ferrara

6. Financial Requests

7. Pubblications/Conferences 2017
G. Bencivenni et al., “Performance of µ-RWELL detector vs resistivity of the resistive stage”, submitted to Nucl. Instr. & Meth. - NIMA-D
G. Bencivenni et al., “ The micro-RWELL”, 2017_JINST_12_C Proceeding of the International Conference on Instrumentation for Colliding Beam Physics, Budker Institute of Nuclear Physics,Novosibirsk, Russia 27 February – 3 March 2017.
G. Morello et al., "Advances on micro-RWELL gaseous detector", submitted to PoS (Proceeding of Science), Proceeding of the 55th International Winter Meeting on Nuclear Physics, Jan 2017.
M. Poli Lener et al.,” The micro-RWELL detector”, submitted to JINST, Proceeding of the 5th International Confernece on Micro-Pattern Gas Detectors (MPGD 2017), Temple University, Philadelphia,USA, May 22-26, 2017.