1. Protection layer test device Fred Hartjes NIKHEF Protection layer meeting Nikhef Dec 4, 2015

2. Fred Hartjes 2 Protection layer meeting. Dec 4, 2015 Based on dedicated Micromegas board uDesigned by Harry uMounted on glass fibre epoxy frame l25 x 25 mm uPitch 80 µm, gap 50 µm uFabricated at CERN (Rui De Oliveira)

3. Fred Hartjes 3 Protection layer meeting. Dec 4, 2015 Laid down on (dummy) chip Micromegas Dummy chip Joop’s double sticky tape uPressed down by silicon rubber wires uElectrical spring contact made by W-Au wires l200 um (Micromegas) l30 um (dummy chip) uMicromegas voltage by MiniHV uField voltage by Wenzel uAll controlled by LabVIEW

4. Fred Hartjes 4 Protection layer meeting. Dec 4, 2015 Protection layer test device u4 channels uPCB sandwiched by insulating gas envelope and aluminium connector frame uMicromegas signal read out by Honeycomb strip amp Coppered kapton cathode Plastic blocks to guide the Micromegas Silicon rubber wire

5. Fred Hartjes 5 Protection layer meeting. Dec 4, 2015

6. Fred Hartjes 6 Protection layer meeting. Dec 4, 2015 LabVIEW DAQ uMicromegas current registered by LabVIEW lnA resolution l0.5 s sample rate uNormal grid current low (few nA) uSpark discharge easily detected (few µA spike) uGrid current sampled every 0.5 s lAll 4 channels individually

7. Fred Hartjes 7 Protection layer meeting. Dec 4, 2015 Properties and prospects uNew samples can be rapidly installed lGas frame easily removed (only gas connections with quick couplings) lSpring contacts (W-Au wire) on sample and Micromegas lNo gluing, wire bonding or soldering required uRather small gas volume (~85 ml) uIrradiation with sources ( 90 Sr and 55 Fe) well possible uAnalog RO of grid signal possible lGain measurements using 55 Fe uIn production lParts (mechanics + PCB) expected mid January 2016