1. Concept for LOKI detector system

2. Rear Detector 2 Spider Cob (central detector) Octant (Out detector) Maybe subdivided in two parts

3. 3 Rear Detector To cover the required area: N.2 Spider Cob N.8 Octants Detectors tilt angle: 3°

4. The Spider Cob 4 The Grid: (Al 3 mm thick) 23 cm 11 cm The Spacer frame (FR4 1mm thick) The 4 sectors GEM. (Frame thickness to be studied)

5. Spider Cob: The ReadOut PADs 5 512 channels read by 16 GEMINI cards (2 GEMINI chips per card) 2 FPGAs

6. Spider Cob: Assembly 6 Stack of 24 Grids and 24 FR4 Spacer Frames3 GEM foils Readout with 16 GEMINI cards orthogonal to the Readout plane

7. The Octant: Grids set 7 10 cm 19 cm 10 cm 15 cm 10 cm 23 cm 10 cm 15 cm X 2 X 1

8. The Octant: Spacer Frame and GEM 8 Ideal 10 Sectors GEM Foil This solution can be followed if we can keep the frame width less then 5mm. In order to understand this we will perform some tests on stretched kapton. Spacer Frame And possible solution for GEM frame FR4 Frame use to separate and to assembly the grids. This can be a possible solution for the GEM frame if the tests on the ideal GEM foil failed. With this GEM frame, the GEM sectors will be different (not already designed).

9. The Octant: ReadOut PADs 9 Designed with different ϕ sector number in order to reduce the dimensions of the bigger pads 1024 channels read by 32 GEMINI cards (2 GEMINI chips per card) 4 FPGAs

10. The Octant: Assembly 10 Stack of 24 Grids Assembly (24x6 grids) and 24 FR4 Spacer Frame 3 GEM Frames Readout with 32 GEMINI cards orthogonal to the Readout plane

11. Rear Detector: (very) Preliminary design of the detector box 11 Detector Box (Neutrons come from the front) Rear Detector Box lid with electronics interfaces

12. 12 Rear Detector: (very) Preliminary design of the detector box Requirements: reduced amount of material in the neutrons path BANDGEM detectors volume filled with Ar/CO 2 mixture (1 atm) FPGAs in air for cooling Integrated alignment system for the detectors in the detector box Groove for Viton o-ring Middle rib: Designed with a tilt angle equal to the tilt angle of the detectors. This rib helps to reduce the thickness of the front side of the box. Stress analysis is required in order to understand how many ribs we need to keep the thickness within the limits. Which is the limit??

13. 13 Rear Detector: (very) Preliminary design of the detector box lid CF DN100 Flange. Connected to a flexible pipe in Air. Flaxible pipe can contain: the Ethernet cables coming out from the 36 FPGAs, the Gas pipe of Ar/CO2, the HV cable. FPGAs container. This can be filled with air. Both side of this container are at room pressure. No vacuum barrier needed

14. Solution with GEMINI in air 14 Advantages Electronics in air Disadvantages Longest path from readout PAD to the GEMINI chip The mechanical integration of this interface with the detector box can be an issue Maintenance issues GEMINI power consumption=160 mW

15. Charge Extraction measurments with BANDGEM 1.0 15 The full Lamella System. A total of 48 lamellas have been mounted mounted. Their distance is 2 mm Assembly with Triple GEM detector 128 Pads of area 6x12 mm 2 have been used as anode

16. Charge Extraction measurements 16 X-rays from side: Study charge extraction at different depth

17. Integrated over threshold counts VS Z coordinate (Near Cathode=0mm, Near GEM=32mm)

18. Recorded spetrum (4000V Applied on the lamellas) at different Z coordinates Copper Peak