1. BANDGEM Demonstrator: conceptual design and state of the art

2. Comparison of the conversion efficiency for different geometries Actual geometryNew geometry

3. Electrons extraction B4C=3mm GAS=1mm 4mm Volumetric Simulation (1000 e-) Diffusion ON Good Electron 1000, Out Electron 544 Percentage 54.4 Volumetric Simulation (1000 e-) Diffusion OFF Good Electron 1000, Out Electron 670 Percentage 67 B4C=2mm GAS=2mm 2mm Volumetric Simulation (1000 e-) Diffusion ON Good Electron 1000, Out Electron 263 Percentage 26.3 Volumetric Simulation (1000 e-) Diffusion OFF Good Electron 1000, Out Electron 486 Percentage 48.6 Actual GeometryNew Geometry

4. New Charge Extraction simulations OLD SIMULATION Prototype NEW SIMULATION Demonstrator IDL&Garfield++ Simulation taking into account the real absorption point of the neutrons Using a threshold of 120 keV we obtain an extraction efficiency of 70%.

5. Prototype - AchievedDemonstrator - Projected Lamella Distance2 mm4 mm B 4 C/empty ratio on lamellas13 Full Lamella System lenght6 cm9 cm Lamella Thickeness250 µm20 µm Lamella MaterialAluminium OxideAluminium Optimal tilt angle7 degrees5 degrees Pulse Height Threshold70 keV120 keV Cathode geometry10x10 cm2 - SquareTrapezoidal Count Rate Capability10 MHz/cm 2 12 MHz/cm 2 Gamma Ray Sensitivity5*10 -5 10 -7 Measured Efficiency @ 1.5 Å18.5%// Expected Efficiency @ 1.8 Å21.2%33% Expected Efficiency @ 4 Å49%64% Front-end ASICCARIOCA – 8 channels/chipGEMINI – 16 channels/chip Performance: Prototype and Demonstrator

6. The BANDGEM umbrella for LOKI Total active area: 647 cm 2 337 mm 400 mm Cathode 8 Lamellae system 96 GEM 1 6 GEM 2 2 GEM 3 2 Readout anode 2

7. Detector Assembly – The cake Aluminate mylar cathode Lamellas system Triple GEM Readout anode

8. The aluminated mylar cathode Production method: The aluminate mylar foil is stretched using the TendiGEM device Its vetronite frame is than glued on it using the rad-hard certified glue

9. Lamellae system A total of 100 lamellae will be installed in the BandGEM demonstrator 22 mm 351 mm... Each lamella is composed by a front frame, 24 aluminum strips and two columns that protect the strips in the back side of the frame. 96 mm 3 1 Protection columns Front Frame Al strips

10. GlassAlumina Low neutron interaction Lower density (2.49 g/cm 3 ) Higher density (3.95 g/cm 3 ) Easy to workHard to work FragileStronger than glass CheapExpensive Possibility to reduce the actual dimensions The actual dimensions cannot be scaled Lamellae frames 6 107 Holes for align the front frame and the protections Weaker point (the horizontal parts will be removed after the installation). Front frame thickness: 1.9 mm SiO 2 : 71.5% Na 2 O: 13.9% K 2 O:0.2% CaO:8.3% MgO:4.4% Al 2 O 3 : 1.3% SO 3 : 0.3% Fe 2 O 3 :0.08% The frames will be made using a water cutting machine (high precision/low cost process) Materials

11. Lamellae system: production method The lamellae will be realized using the TendiGEM device. The aluminum foil (thickness=15 µm) will be stretched in the TendiGEM, and after the stretching the front frame will be glued on it using the “TermoGuss2000” rad-hard glue. The assembly frame+aluminum foil is then sent to the laser cutting service in order to cut the aluminum and produce in this way the strips and the contacts. The protective columns are than glued on the back side of the frame in order to protect the Al strips and to avoid the formation of conductive paths between the strips due to the B 4 C coating. The strips are ready to be coated with B 4 C.

12. Lamella system: production method When the coating process is finished, the lamellae are ready to be install inside the detector. The lamellae will be sandwiched between 2 trapezoidal alumina or fiberglass frame (one near the cathode, the other near the first GEM foil) which present a pair of pockets for each lamella. Pair of pockets for the first lamella When all the lamellae are sandwiched between the 2 trapezoidal frames, they will be glued inside the pockets. At this point all the frames are constrained to the trapezoidal frames, so we can break the horizontal parts of the glass frame and the strips will remain in position.

13. GEM Foil The GEM foils will be realized at CERN and they will be glued to their frames using the same technique used for the production of the cathode. Each GEM foil will be sectorized in 8 sectors, in order to reduce the possible damage caused by a spark. A total of 3 GEM (triple GEM) will be installed in the detector and the gap between each GEM (Transfer gaps) is equal to 2mm. All the GEM foils will be sandwiched and glued on the upper trapezoidal frame.

14. Padded Anode The anode will be composed by 1024 pads. The the size of the pads is between 7.7 and 137 mm 2. The maximum pad size is similar to the one of the nGEM for SPIDER, and we have already tested the low noise level. The PADs is divided into 10 ϕ sectors, while the dimension of the PADs is constant along the y- coordinate and equal to 4mm. At the moment only the PADs were designed, while the position of the read-out electronics is still under investigation. The design of the read- out electronic position will be decided after the test of the GEMINI Chip. The anode will be glued on the GEM3 frame, and the gap between the GEM3 and the PADs (induction gap) will be equal to 2mm. y ϕ

15. Small Area Prototype- for testing In order to test the technology processes that will be used for the construction of the demonstrator and to validate the numerical simulation as soon as possible, it was decide to made a small scale prototype (active area=10x10 cm 2 ). 115 mm 107 mm With this detector we can test the production method of the lamellae system (it is the same of the demonstrator) and we can validate the numerical simulations. It will be composed by 25 lamellae (all with the same dimensions) and the 10x10 triple GEM system with its cathode will be the same of the actual BandGEM (and of the other 10x10 GEM detectors such as the bGEM). This should allow the production and the test of the detector up to the end of this year.

16. Future improvements The design of the demonstrator can be further improved in the future. In fact, by using the glass as material for the lamellae frames and a 5-axis water cutting machine (the actual manufacture will buy it during the next year), is possible to obtain an optimized design, with a reduce amount of inert material inside the detector and than a reduce contribution of the scattered neutrons. 6 90° 3 112.5° 9 4

17. State of the art – Detector Components and Materials We should have all the materials before/immediately after summer holydays in order to start building the 10x10 prototype for testing ComponentMaterialProviderComment LamellaAl Alloys 1200, 1050° (Al>99%), 8079, 8011 (1% Fe) Korff AG (CH)All Alloys orderd in thickness of 15 and 30 μm Lamella FrameGlassAG Vertec (B)Suggested by F. Sauli, Orderd Frame/Lamella GlueThermoguss 2000Harold Patscheider GmbH Stands > 1000°C, Rad-Hard (CERN database). Tested up to 400° C GEM FoilsKapton+CopperCERNNeed to be designed GEM Frames & Lam. System Franes Fiberglass/GlassMeroni & Longoni (IT) Need to be resistant Padded AnodeFiberglass + CopperArtel (IT)Need to be designed Resistor chain + supporting columns FiberglassArtel (IT)Resistor chain to be decided

18. Cross Section Glass