Central Tracker review

1. Central Tracker review Micromegas central & forward tracker • R&D and prototypes • CAD implantation study • Interfaces

2. Clas12 R&D on detectors • CLAS12 R&D and prototype in 2009 • Bulk in high magnetic field at Jlab • Spark rate with alpha source • Spark rate with muon and hadron beam at CERN • Resistive kapton film prototype • Development on curved drift with X tile prototype • Cosmic bench for future prototypes MIP’s characterization • CLAS12 R&D and prototype in 2010 • Spark rate with alpha source at 1.5 Tesla • Forward prototype (thin flat, segmented mesh) • Y tile prototype • Beam at CERN (forward, gas studies,…) • Beam test at Jlab ?

3. Micromegas tracker:CAD study

4. CLAS12 Micromegas tracker CAD Study • The CAD study for MM implantation was done in 2007 for feasibility • The The study was based on successful technical solutions validated by experiments before 2007 • This study was done on a mixed solution for the central tracker • two double silicon tracker layers at low radius and three double Micromegas layers at higher radius. • The forward tracker was based on Micromegas solution with three double layers.

5. Central tracker mixed solution: Si +µM • Symbiosis between Si and µM: to be studied: • Mechanics • Common tracker structure • Common alignment system • Localization in space for minimum dead zone and maximum spatial resolution • Common connectors and/or flex cables • Electronics • Common ASIC • Common Concentrator • Common DAQ • Collaboration on various topics mentioned above during the development phase.

6. Central Tracker CAD study Magnet Forward tracker Central front end electronics Forward front end electronics Micromegas central tracker

7. Tracker dimension • Each layer of detection is composed of two MM detectors with X and Y strips at 90°. The usability of a single X-Y detection PCB board will be studied in 2009 • The bulk maximum size is 600 mm x 800 mm. • The cylinders where divided in three sectors to match dead zone

8. Demonstrator tile: detector structure • Each bulk PCB is mechanically fixed to a light structure which sets its curvature. The shape and material will be studied for low material budget. The mylar drift window is glued on the bulk active area. Detector structure Detector structure with bulk Demonstrator picture

9. CAD study: tile and dead zone • In this first study we have a rather large dead zone of 30 mm between adjacent tile active area. Further studies will be done to reduce the dead zone and match Si (tbc). • The no dead zone configuration imply overlap of tiles (complex structure) Flex connection Active area

10. CAD study: central structure • The central structure will hold the bulk tiles on several radii for the barrel and at several positions for the forward disk. • Each tile will be extractable from the structure independently from the others. • The whole structure with its detectors and electronics will be extractable from the magnet through a slide rail system. Location for disk bulk (forward) Location for electronic Si tracker HT cable and gas (volume representation) Location for curved bulk

11. CAD study: central structure with µm tiles • The electronics box will be hooked to the central strucrure allowing: • Box dismounting • Single flex disconnection • FE and concentrator card access. Flex for forward tracker Electronic FE and concentrator Forward tracker (magenta) Central tracker (blue)

12. CAD study: central structure- cut view • The cylinder layers are divided in three sectors in the 2007 study. Barrel tracker (blue) Gas pipe distribution (violet) Dead zone between sectors

13. CAD study: Forward Micromegas Tracker • The forward tracker consisted in three layers of flat disks. Each disk is two faced with U strips on one side and V strips at 60° on the other side. Each disk side is divided into 3 sectors (6 in the most recent simulation). • The disks are located just after the cylindrical tracker every 15 mm. The sectors of each twin disk are not aligned to avoid dead zones (tbc). Central tracker FMT : 6 disks piled up

14. CAD study: FMT, dimension • To obtain a thin flat Micromegas, the PCB has to be set on a support. We first considered to use the COMPASS technique using a 3 mm thick Nomex honeycomb panel on which the 100 µm thick PCB is glued and the detector stays flat. • The exact cutting of the disk is not yet definied

15. CAD study: flex for FE readout • In order to located the front end electronic at the rear of the tracker we will use 800 mm long flex. • The flex will be going between the CTOF and the last central tracker layer. FMT flex 5° cone from target Central Si detector Forward µm detectors Central µm detector

16. CAD study: FMT mesh segmentation • In order to reduce dead time due to discharges when there is high occupancy at low radii, the mesh will be divided in several (2 in this study) independents areas. While sparking in inner region, the detector will still be operating in the outer region. An R&D on mesh segmentation will be done in 2009-2010 to study the minimization of the dead area between the two mesh surfaces and to validate the concept on a prototype in beam ( dead zone < 1mm) . Active area Mesh segmentation

17. CLAS12 CT internal interfaces • We need the space allocation for each sub system to go further in CAD studies • Can be done when final choice are made (i.e. MM for barrel) and constrains of each sub system studied together. • We need a Coordinator for the CT: • Interface can be worked with neighbor and proposed to CTC • Common 3D CAD model updated every 6 month • Assembly plan • Budget: weight, heat load, power consumption,… • CT meeting every year for a Preliminary Design Review in 2011

18. CT a Russian doll integration Limited space budget: crowded inside !! • Interfaces • Mechanical • Electrical • Thermal • Accessibility • detectors • Electronics • Servitude • Gas • HT • Signal,…/… Magnet HTTC Neutron detector Ctof MM barrel MM Forward Si barrel Cryotarget

19. MM electronic location • The maximum distance between MM detectors and the front end electronics is around 1 meter. two options: • In the tube: we fit in the fixation tube (around SVT elec. ?) • Uneasy fixation and access, cooling needed, open tube ? • Outside the tube: we fit around the fixation tube • Longer distance to detector, easy fixation and access, hole in tube, interface with light guide lines. In tube barrel elc. Forward elc. Outside barrel elc. Forward elc.