S. AUNE 15/09/08 Micromegas Bulk for CLAS12 tracker

S. AUNE 15/09/08 What is a MicroMégas ? ~100  m thin gap Fast ions collection

S. AUNE 15/09/08 What is a bulk Micromegas ? The basic idea is to build the whole detector in one process: the anode plane with the copper strips, a photo resistive film having the right thickness, and the cloth mesh are laminated together at high temperature, forming a single object. By photolithographic method then the photo resistive material is etched producing the pillars. 12 to 24 mm Photoresist border PCB with strip Drift spacer:  1 to 2 mm drift spacerDrift window 3 mm Photoresist amplification spacer + drift spacer base 5 mm

S. AUNE 15/09/08 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 MM tracker Project

S. AUNE 15/09/08 Resolutions comparison (Sébastien Procureur) 4 x 2MM4 x 2SI2 x 2SI + 3 x 2MM Specs.  pT /p T (%)   (mrad)   (mrad)  z (μm) tbd. (for 0.6 GeV/c,  = 90°)  The mixed solution benefits of advantages from both SI and MM!  The « Si only » solution is never the best…

S. AUNE 15/09/08 Planning clas12: bulk tracker FeasibilityDefinitionDevelopmentproductionPhysic ABCDE project Phase JalonPDRPRRFDR Faisabilité: résolution spatiale sous B + bulk mince (X 0 = LR) Collaboration Decision : central tracker: Si and/or bulk Forward Vertex Tracker: bulk? Pure Si 300 µm = 32 x 10-4 LR

S. AUNE 15/09/08 Phase A: Feasibility 1.Mechanical & electronic implantation ? –Mechanical implantation –Remote read out electronic ? 2.Thin bulk micromegas ? –Existing flat detector –Prototypes: PLV1, PLV2 3.Gaseous detector in 5T field ? –1.5 T and 5T tests vs simulation

S. AUNE 15/09/08 Mechanical & electronic implantation ? The study was done with curved detector. 4 double, X and Y strips at 90°, cylinders around the target with a 3 double end cap. Electronic needs to be close ? –(compass: 300 mm) 2 studies where done: close and remote.

S. AUNE 15/09/08 3D close-elec. model Drawings to show difficulties and help to find solutions Front electronic very hard to install

S. AUNE 15/09/08 3D remote-elec. model Good solution to be validated with long (> 800 mm) electronics braids

S. AUNE 15/09/08 Thin bulk micromegas ? PLV1 test (protoype long version 1) Goal: test thin (15 x 10-4 LR), long (600 mm) detector with a remote (800 mm) ASIC (AFTER chips, T2K)

S. AUNE 15/09/08 Noise measurement Flex PCB cable tests :  Strip cables (40cm, 80cm et 80cm U-shaped)  Wire cables (40 cm, 80cm et 80 cm U-shaped) 55 Fe source tests Flex PCB cable, 80 cm U-shaped Acquisition made with T2K Labview DAQ Software

S. AUNE 15/09/08 Long Prototype study with 55 Fe Energy resolution Homogeneity of the detector

S. AUNE 15/09/08 AFTER signal on the strips Signal Time (x 50 ns) ADC 55 Fe shaped signal Signal - noise Noise Channel time samples

S. AUNE 15/09/08 Noise study: preliminary results Pedestal for channel 71

S. AUNE 15/09/08 Summary (preliminary) 0- Electro. Only 1- FEC + Det 2- Flex PCB cable 40 with Strips 3- Flex PCB cable 40 with wires 4- Flex PCB cable 80U with Strips 5- Flex PCB cable 80U with Wires 6- Flex PCB cable 40 x 2 7- Flex PCB cable 2 m Probably not real Without noise optimization: noise with 80cm flex cable ~6 for MIP signal expected ~50. => Flex PCB cables up to 80cm are definitely useable !

S. AUNE 15/09/08 Thin bulk micromegas ? PLV2 test (protoype long version 2) Goal: –Realize curved detector (X and Y): One bulk PCB to be curved in its length (Y) or in its width (X) –Test detector in DVCS magnet at 5 T –Assembly of a demonstrator for beam tests using T2K electronics (1728 channels)

S. AUNE 15/09/08 PLV1 curved tests One prototype was curved on a Y structure. We obtained a good gain homogeneity and E resolution degrade to 40%.

S. AUNE 15/09/08 Y cylinder X tile Y connector Y HT cable Y joint Interface attachment to handcart Length: 600 mm Diameter: 180 / 220 mm Magnet interface (3 Teflon pads) Cylindrical prototype Curved bulk demonstrator

S. AUNE 15/09/08 Curved bulk integration

S. AUNE 15/09/08 Cylindrical prototypes tests 1 st Fe 55 observed on a curved bulk (  E/E ~ 28% for flat bulk ) 38.3% FWHM

S. AUNE 15/09/08 Cylindrical prototypes tests X curved Energy resolution degraded due to in-homogeneity in the amplification gap. The gain are similar but shifted in tension (gap smaller)

S. AUNE 15/09/08 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 ?

S. AUNE 15/09/08 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

S. AUNE 15/09/08 Lorentz angle behaviour with the magnetic field (2)

S. AUNE 15/09/08 Lorentz angle behaviour with the drift HV

S. AUNE 15/09/08 « Spatial resolution » Sigma of the average position calculated event by event σ² exp =(σ 2 laser+ σ² det )/N When the magnetic field increases → the resolution increases Test the detector homogeneity B = 0T B = 1.5T

S. AUNE 15/09/08 Out In 400 mm Test at 5T Test to be done in the coming month 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.

S. AUNE 15/09/08 Electronics for CLAS12 tracker Development of an ad hoc ASIC possible. –On time hit strip chip. –3 year development program –R&D to be started when approval by the collaboration of a gaseous tracker.

S. AUNE 15/09/08 Phase A: Feasibility: 80% done 1.Mechanical & electronic implantation ? –Yes we can design a detector with a remote electronic 2.Thin bulk micromegas ? –Yes flat and thin detector validated. –Curved still to be studied for energy resolution and fabrication process improvement. 3.Gaseous detector in 5T field ? –Yes for 1.5 T; test ok with simulation Lorentz angle: 15° high drift field. –5 T test to come for confirmation. Phase B; Definition to started in 2009 ?