Quality test of GEM foils Jlab 12 Meeting
Quality test of GEM foils Jlab 12 Meeting Roma – 09/06/2011 Jlab 12 – Group GEM Jlab 12 Meeting 09/06/2011 Roma Quality test of GEM foils Keithley 6517 B Programmation Valérie De Smet Francesco Librizzi Michele Mangiameli V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 1/9
Quality test of GEM foils Overview 1 Quality control of GEM foils 2 Procedure for the HV test of a GEM foil 3 Labview program for 1 sequence 4 Next steps V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 2/9
Quality test of GEM foils 1 Quality control of GEM foils • Quality control of GEM foils : - visual inspection with microscope - HV test • Possible defects, that change the amplification properties of the GEM foil : - etching defects of GEM holes e. g. enlarged holes, cracks in kapton, missing/overhanging cupper - dust/impurities - missing holes • HV test principle : - Place GEM foil inside a Plexiglas box flushed with N 2. - Apply voltage between the 2 Cu-coated sides of the GEM foil (up to 2 x Voper of GEM foil) and measure leakage current (should be smaller than e. g. 1 n. A in our case). - Discharges can occur which could damage the GEM foil => the applied voltage should be increased progressively, in « steps » . • HV test on one GEM foil should be performed : - before gluing - after gluing the GEM foil to its frame - after gluing the framed GEM foil to the GEM module under construction V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 3/9
Quality test of GEM foils 2 Procedure for the HV test of a GEM foil V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 4/9
Quality test of GEM foils 3 Labview program for 1 sequence - Checking the value of the stabilized current in a landing is not incorporated yet. - Output file (time, voltage, current) can be generated on request. V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 5/9
Quality test of GEM foils 3 Labview program for 1 sequence START Generalized « flow chart » CONFIGURATION SERIAL PORT NO INSERTED PARAMETERS COHERENT? YES SETTINGS KEITHLEY APPLY VOLTAGE(V) DISPLAY ERROR MESSAGES MEASURE CURRENT WRITE CURRENT AND VOLTAGE IN TXT FILES NO V=VFinal ? YES CLOSE SESSION SERIAL PORT END V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 6/9
Quality test of GEM foils 3 Labview program for 1 sequence V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 7/9
Quality test of GEM foils 3 Labview program for 1 sequence V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 8/9
Quality test of GEM foils 4 Next steps Improving the existing program : - Allow the several sequences (with parameters for time) - Include a control of the current value - In case the current in a « landing » is larger than 1 n. A : include a sequence to decrease the voltage until a « safe » value, at which the voltage will remain constant for as long as the operator decides. Thank you very much … Grazie tanto … Merci beaucoup ! V. De Smet – F. Librizzi - M. Mangiameli Jlab 12 Group GEM Catania Meeting Roma 09/06/2011 9/9
- Slides: 9