RD S. Aune CEA/IRFU Micromegas Bulk for CLAS12 vertex tracker

RD S. Aune CEA/IRFU Micromegas for CLAS12 Micromegas (MM) as central tracker for the CLAS12 experience at Jlab in 2014 CAD Study and remote electronic Curved Bulk prototyping and tests – Saclay bulk test 2007 – CERN Prototyping and tests in Saclay 2008 MGPD in 5T field –Lorentz angle study and test First curved: Saclay 2005

RD S. Aune CEA/IRFU Vertex tracker why Gaseous, compared to Si ? Less material (~.0015 L R ) Larger ΔR → same intrinsic momentum and angle resolution for less channels smaller dead zones Cheaper Resistant: “immortal while breathing”

RD S. Aune CEA/IRFU Mixed solution: Silicium + Micromegas bulk Central detector –2 planes of Silicium (X,Y) –3 cylindrical bulks (XY): 3m 2, pitch 0.6 mm,10k channels. Forward detector –4 plane bulks (XY): 1 m 2, 3k channels. 600 mm for  500 mm FVT Silicium target Cylindrical bulks beam Bulk tracker Project for CLAS12 at Jlab

RD S. Aune CEA/IRFU Mechanical & electronic implantation ? Conclusion: Mechanical implantation possible Curved detector for “Y strip” Electronic needs to be remote “As Far As Possible” (compass: 300 mm) –Test done on long kapton braid Study of a ad hoc ASIC for tracker to be decide A CAD study was done with curved detectors. 3 double, X and Y strips at 90°, cylinders around the target with a 3 double end cap.

RD S. Aune CEA/IRFU 3D remote-elec. model Good solution to be validated with long (> 800 mm) electronics braids

RD S. Aune CEA/IRFU Saclay Bulk Lab (2007) PCB used: FR4 from 60 to 200 micron Kapton 25 to 100 micron mesh used: Woven wire 19 micron The thin PCB is transformed in bulk flat and then curved. The Detector are made in a bulk lab using PCB machines design for university. The ability to realize the bulk allowed fast R&D with several configuration

RD S. Aune CEA/IRFU PCB: 100 µm FR4 with 5 µm thick Cu strip 100 µm amplification gap Woven Mesh Gantois non stretched bulk with an array of 400 µm pillar every 2 mm Dimension: 180 mm x 60 mm First curved bulk ( ) Picture: bulk curved, 100 mm radius

RD S. Aune CEA/IRFU First prototype test 15 proto realize, 14 tested  E/E ~ 40% vs 25% on thick bulk 1 er Fe 55 pick on a curved bulk Study for drift pillar

RD S. Aune CEA/IRFU Thin bulk micromegas Prototype made at CERN (2008) Thin bulk (15 x 10-4 LR), long (600 mm) detector with a remote (800 mm) ASIC (AFTER)

RD S. Aune CEA/IRFU PLV1 curved tests One prototype was curved on a Y structure. We obtained a good gain homogeneity and E resolution degrade to 40%. Before drift integration Under test Drift integration

RD S. Aune CEA/IRFU Curved bulk integration

RD S. Aune CEA/IRFU Curved bulk integration Issue to be solved –Temperature curing during bulk fabrication process: differential thermal dilatation on thin PCB –Tension on the mesh vs. curvature Sealed drift –A 100 µm aluminize mylar is silicon glued with a 2 mm thick silicon join on the PCB. Gaz capillary tube glued either on drift or on PCB

RD S. Aune CEA/IRFU Gain on curved bulk First test under way, similar gain behavior with small increases depending of curvature.

RD S. Aune CEA/IRFU Before curvature energy calibration Energy resolution

RD S. Aune CEA/IRFU Energy resolution degraded due to in-homogeneity in the amplification gap % FWHM versus 20% flat Possible solution: Nylon/metal mesh Curved process pcb mesh Curved bulk energy resolution

RD S. Aune CEA/IRFU Flexible cable measurement Different flex PCB cable were realise at CIRE/SPCI:  Strip cables (40cm, 80cm et 80cm U-shaped)  Wire cables (40 cm, 80cm et 80 cm U-shaped) Noise and crosstalk measurement test were conclusive for 800 mm. Flex PCB cable, 80 cm U-shaped Acquisition made with T2K Labview DAQ Software

RD S. Aune CEA/IRFU AFTER signal on the strips Signal Time (x 50 ns) ADC 55 Fe shaped signal Signal - noise Noise Channel time samples

RD S. Aune CEA/IRFU Noise study: preliminary results Pedestal for channel 71

RD S. Aune CEA/IRFU Magnetic environment to deal with : 5 T orthogonal to the detector ! e-e- tanθ = v x B / E Standard conditions : E= 1 kV/cm, v= 8 cm/μsec θ = 75 ° Adapted conditions: E= 10 kV/cm, v= 5 cm/μsec θ = 14° Gaseous detector in 5T field ?

RD S. Aune CEA/IRFU Lorentz angle behaviour with the magnetic field Lorentz angle mesured from the deviation of the B=0T peak Drift distance: 2.25mm The signal spreads out with the Lorentz deviation → increase the resolution B = 0T B = 1.5T Labview DAQ

RD S. Aune CEA/IRFU Lorentz angle behaviour with the drift HV

RD S. Aune CEA/IRFU Out In 400 mm Test at 5T Test done at Jlab on the DVCS magnet. The prototype is fixed on a mobile cart (telescopic slide rail) itself fixed on the magnet. The handcart allows full test in and out without dismounting the detector. Will be used for future 5T with DVCS magnet.

RD S. Aune CEA/IRFU Y cylinder X tile Y connector Y HT cable Y joint Interface attachment to handcart Length: 600 mm Diameter: 180 / 220 mm 1728 Channels Magnet interface (3 Teflon pads) Cylindrical prototype Curved bulk demonstrator