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

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

3. 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

4. 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

5. S. AUNE 15/09/08 Resolutions comparison (Sébastien Procureur) 4 x 2MM4 x 2SI2 x 2SI + 3 x 2MM Specs.  pT /p T (%) 2.92.11.65   (mrad) 1.315.11.410   (mrad) 10.92.92.65  z (μm) 2121522267tbd. (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…

6. S. AUNE 15/09/08 Planning clas12: bulk tracker 2007 0809101112132014 FeasibilityDefinitionDevelopmentproductionPhysic ABCDE project Phase JalonPDRPRRFDR Faisabilité: résolution spatiale sous B + bulk mince (X 0 = 11 10-4 LR) Collaboration Decision : central tracker: Si and/or bulk Forward Vertex Tracker: bulk? Pure Si 300 µm = 32 x 10-4 LR

7. 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

8. 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.

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

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

11. 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)

12. 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

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

14. S. AUNE 15/09/08 AFTER signal on the strips Signal Time (x 50 ns) ADC 55 Fe shaped signal Signal - noise Noise Channel 71 512 time samples

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

16. 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 !

17. 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)

18. 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%.

19. 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

20. S. AUNE 15/09/08 Curved bulk integration

21. 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

22. 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)

23. 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 ?

24. 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

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

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

27. 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

28. 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 test @ 5T with DVCS magnet.

29. 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.

30. 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 ?