January 7th, USTC, Hefei 1 A CGEM Prototype for BESIII Inner Drift Chamber Upgrade R. Baldini Ferroli, (INFN-LNF) for a China-Italy Collaboration Project Co-financed by the Italian Ministry for Foreign Affairs (MAE)

January 7th, USTC, Hefei 2 Outline  BESIII requirements for a CGEM Inner Tracker  Prototype targets  LNF CGEM miniworkshop  Assembling a KLOE2 CGEM  GASTONE32 analog readout  Possible improvements

January 7th, USTC, Hefei 3 QUN OUYAN at the CGEM workshop

January 7th, USTC, Hefei 4 GEM: principle of operation By applying V between the two copper sides, an electric field as high as ~100 kV/cm is produced into the holes which act as multiplication channels for electrons produced in the gas by a ionizing particle. Gains up to 1000 can be easily reached with a single GEM foil. Higher gains (and/or safer working conditions) are usually obtained by cascading two or three GEM foils. A Triple-GEM detector is built by inserting three GEM foils between two planar electrodes, which act as the cathode and the anode. LHCb geom The GEM (Gas Electron Multiplier) [F.Sauli, NIM A386 (1997) 531] is a thin (50 μm) metal coated by a kapton foil perforated by a high density of holes (70 μm diameter, pitch of 140 μm)  standard photo-lithographic technology.

January 7th, USTC, Hefei GEM detector features  flexible geometry  arbitrary shape: rectangular, cylindrical …  ultra-light structure  very low material budget: <0.5% X0/chamber  gas multiplication separated from readout stage  arbitrary readout pattern: pad, strips (XY, UV), mixed …  high rate capability: >50 MHz/cm2  high safe gains: > 10 4  high reliability: low discharge, P d < per incoming particle  rad hard: up to 2.2 C/cm 2 integrated over the whole active area without permanent damages (corresponding to 10 years of operation at LHCb1)  high spatial resolution: down to 60µm ( COMPASS with analog readout Nucl.Phys.Proc.Suppl. 125 (2003) )  good time resolution: down to 3 ns (with CF 4 ) 5

January 7th, USTC, Hefei 6 6 m 7m7m Lead/scintillating fiber 98% coverage of solid angle 88 modules (barrel + end-caps) 4880 PMTs (two side read-out) Lead/scintillating fiber 98% coverage of solid angle 88 modules (barrel + end-caps) 4880 PMTs (two side read-out) 4 m diameter × 3.3 m length 90% helium, 10% isobutane 12582/52140 sense/tot wires All-stereo geometry 4 m diameter × 3.3 m length 90% helium, 10% isobutane 12582/52140 sense/tot wires All-stereo geometry Electromagnetic Calorimeter Drift Chamber  r  = 150  m  z = 2 mm  V = 3 mm  p /p = 0.4 %  r  = 150  m  z = 2 mm  V = 3 mm  p /p = 0.4 %  E /E =5.4%/  t = 54 ps/  E /E =5.4%/  t = 54 ps/ 100 ps(calib)  100 ps(calib) B = 0.52 T KS = 0.6 cm KL = 340 cm K = 95 cm

January 7th, USTC, Hefei 7 To improve vertex reconstruction of K s, η and η’ and K s - K L interference measurements: 1.  rφ  200 µm and  z  350µm 2. low material budget: < 2% X 0 K S →     vertex resolution will improve of about a factor 3 from present 6mm  4 CGEM layers :from IP to DC Inner wall  700 mm active length  XV strips-pads readout (~40 o stereo angle)  <2%X 0 total radiation length in the active region 3 mm 2 mm Cathode GEM 1 GEM 2 GEM 3 Anode Read-out Cylindrical Triple GEM Cylindrical GEM detector is the adopted solution KLOE2 Inner Tracker

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9 BESIII CGEM expected spatial resolution  Digital readout KLOE2 (650 µm pitch)  x =190 µm  z ~ 350  m Magnetic field effect : charge spread over the readout plane 190 µm  330 µm  Analog readout high spatial resolution: down to 50µm ( COMPASS,400 µm pitch) Hopefully no magnetic Field effect, since analog readout measures the centroid of the induced charge  x ~ 650/ ~ 80  m  z ~ /190 ~ 150  m BESIII B :  x = 330 mm

January 7th, USTC, Hefei 10 % of X 0 CATHODECopper: 2*3 *1 Kapton: 2*50*1 Honeycomb: 1*3000* Total= GEM foilsCopper: 6*3 *0.8 Kapton: 3*50 * Total= ANODECopper: Kapton: 1*225 *1 Gold : 2*0.1 *1 Epoxy: 2*10 * Total=0.147 CF ShieldCF: 2*90 *1 Honeycomb: 1*5000* Total= Layer: Layers:1.92 KLOE2 % of X 0 CATHODECopper: 2*2 *1 Kapton: 2*50*1 Honeycomb: 1*3000* Total= GEM foilsCopper: 6*2 *0.8 Kapton: 3*50 * Total= ANODECopper: Kapton: 1*225 *1 Gold : 2*0.1 *1 Epoxy: 2*10 * Total= CF ShieldKapton: 2*50 *1 Honeycomb: 1*3000* Total= Layer: Layer:1.56 BESIII Material Budget

January 7th, USTC, Hefei Z resolution Liangliang talk Guilin Coll. Meet.

January 7th, USTC, Hefei Momentum resolution Liangliang talk Guilin Coll. Meet.

January 7th, USTC, Hefei 13 Prototype construction goals  Design,construction and test of a CGEM prototype, in case first layer of a new CGEM Inner Tracking  Design,construction and test of an analog readout system to achieve < 100 µ m xy and < 200 µ m z resolutions  Budget (euros) requested to Foreign Affairs Ministry, following the Agreement of scientific cooperation for a Joint laboratory “INFN-IHEP ” :

January 7th, USTC, Hefei 14 LNF CGEM miniworkshop  October 2012 : 2 days Cylindrical GEM workshop at LNF with Chinese collaborators,KLOE2,BARI,CMD3 and CERN (Rui de Oliveira)  G. Bencivenni (LNF) and collaborators presented the status of KLOE2 Inner Tracking CGEM detector  A. Ranieri (Bari University) presented the analog version of KLOE2 GASTONE digital readout  The second day was dedicated to visit the CGEM laboratory, where a practical assembly procedures demonstration was given  The following slides are a summary of D. Dominici and A. Ranieri talks on CGEM construction, assembling and analog readout

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January 7th, USTC, Hefei 18 GEM Foils GEM FoilThickness (µm) Radiation Length Copper 3 2.1E- 04 Polyimide E- 04 Copper 3 2.1E E-04  GEM foils by CERN TE-MPE-EM with a single-mask chemical etching tuned to produce large size GEM  Present size 1.2m x 0.5m (active area) Future max size 2m x 0.5m  The hole shape is double conical ( ) with a slight asymmetry

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January 7th, USTC, Hefei 28 Detector sealing

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January 7th, USTC, Hefei 31 Detector assembled

January 7th, USTC, Hefei 32 tracking provided by external 10x10 cm 2 Triple-GEM Test with final HV cables, distributors, FEE and DAQ system top/bottom scintillators for trigger Cosmic rays test

January 7th, USTC, Hefei November 2012,BESIII Winter Collaboration Meeting,Guilin 33 KLOE-2 IT Construction Status

January 7th, USTC, Hefei 34  GASTONE32, a 32 channels board with analog readout, already available. It produces an amplified and shaped output of the detector input. (See workshop A. Ranieri presentation )  Funding request to INFN for a small planar (10  10)cm 2 3-GEM (Bari group board in next slide) GASTONE32 with analog readout

January 7th, USTC, Hefei November 2012,BESIII Winter Collaboration Meeting,Guilin 35

January 7th, USTC, Hefei 36  Ar/CO2=70/30  G ~ 10 4  10 primary clusters/3 mm  Clsize ~ 2.3 el/primary Charge/mip ~ 36 fC Charge/mip/strip ~ 9 fC GASTONE32: some test results

January 7th, USTC, Hefei  Cost (kRMB) Toolings available Molds 100 GEM/Anode 250 Readout 450  Time ~ 2 years  MAE Budget: ~ 120 keuro LayerInternal diameter (mm) Length (mm) GEM foils Preliminary estimate layer 1 prototype construction

January 7th, USTC, Hefei  CERN facilities can manifacture foils up to 1µm thick Cu  CF shield can be replaced by kapton  Molds mechanical tolerances could be more permissive  Experts are investigating a new assembling procedure using only 1 mold per layer instead of 5  A biCGEM Further Possible Improvements

January 7th, USTC, Hefei  Material budget down to ~ 1.3 % X 0  Opposite B distortion  Streching -> no molds, no glue A new proposal (Rui de Oliveira and G. Bencivenni)

January 7th, USTC, Hefei Summary  CGEM could be a solution for a new Inner Tracker  A relevant gain is achieved in the longitudinal view  Transverse momentum resolution worsening (?) at low momenta only  A prototype with analog readout in two years, if:  more people join this project

January 7th, USTC, Hefei 41 Thank you for 谢谢 your attention