Thin and high-pitch laser- etched mesh manufacturing and bulking "

1. RD51 Common Projects WG 1 – New techniques Thin and high-pitch laser-etchedmeshmanufacturing and bulking" (INFN Bari, CEA Saclay, CERN) V. Berardi, P. Colas, Rui de Oliveira With help from D. Attié, M. Kebbiri, O. Pizzirusso, W. Wang, and A.Ancona, T. Sibillano, F. Di Niso (CNR)

2. Project startedFeb. 15, 2012 for an initial duration of one year. • Sharing of the tasks: • Bari : improve laser punching technique • CEA Saclay : test of meshes, gain, ion back-flow • CERN: bulkingwithvariousmeshes • Funding: 19 000 CHF (8 000 Bari, 5000 Saclay, 6000 CERN) • Motivation : extend the bulkprocess (so far usingonlywovenmeshes) to thinner and higher-pitch meshes, to optimize ion back-flow, electron collection, and resolution. Favor non-magneticmaterials • Twopaths : laser punching and bulking of new electroformedmeshes Thin high-pitch meshes

3. Progress in laser-etchedmeshes First attempt in Februaryusing double-layer of copper -> no signal. The holeswere not open. Verydifficult to ‘peal’ the mesh. Second attempt (10x10 mm² meshesreceived in Saclay afterStony Brook) : transparency OK. To betested in gas. With the present laser: 10 holes/s. A factor of 5 couldbegained. Thin high-pitch meshes

4. Cost for 8 6’’ x 6’’ coppermeshes : 2529 euro wotax. Payedhalf-half by Saclay and RD51. Wovenmeshes are typically 380-450 lpi Thin high-pitch meshes

5. Thin high-pitch meshes

6. First thin-meshbulk Thin high-pitch meshes

7. Performances testedat Saclay Thin high-pitch meshes

8. Financial report In total, only 4 kCHFwerespent out of 19. Bari benefitedfrom a hugeinvestment (500 K€ from EU) in the CNR laser lab. Thin high-pitch meshes

9. Conclusions • Recently the commonproject on meshes made good progress: First thin-meshbulk made at CERN. • New laser-etchedmeshesready to betested • Main goals willbeattainedwithin initial schedule (beforeFebruary 15, 2013) Thin high-pitch meshes