Status of the RF-box for the VELO Upgrade Frans Mul, Mike de Jong, Johan Kos, Herman Boer Rookhuizen, Eddy Jans, Tjeerd Ketel Slides are for 95% from Tjeerd Status on 26 November 2010 Leak rate test on 15 January 2011 Ongoing work Plans Meeting on the RF Foil for Upgrade

Meeting on the RF Foil for Upgrade2 Procedure for milling an RF-box + flange from one block of material buy the appropriate, i.e. homogeneous, material mill the inside apply a thin layer of resin at the inside fill the inside with Sikadur let it harden mill the outside till a thickness of  1 mm is reached perform thickness measurements mill to final thickness, i.e. 0.3 mm heat setup such that resin melts and the Sikadur filling falls out clean pray it is leak tight

Status on 26 November 2010 Cake-shaped foil on a 3-axes milling machine – Single block of Al Mg4.5 Mn0.7 – Thin layer resin of 1 mm – SIKADUR 31CF filler Inductive measurement – In situ with filler 3D measurement – When filler removed Meeting on the RF Foil for Upgrade3

Filler and cake-shaped foil Meeting on the RF Foil for Upgrade4

Foil thickness measurements [mm] 0.36 mm 0.38 mm L probe (coil)) 3D probe (touch) T.J. Ketel (See backup slides for more information)

Leak rate determination Meeting on the RF Foil for Upgrade6 Leak rate: <10 −9 mbar l/s

Ongoing work Try to produce a short RF-box for a VELOpixed vertex detector of LHCb.

L-shape foil with a 5-axes milling machine Programming of the machine at the VU Actual milling will start soon, i.e. in May Meeting on the RF Foil for Upgrade8 L = 370 mm W= 270 mm H = 155 mm Pitch = 30 mm Depth = 6 mm Step = 16 mm Radius > 6mm

Meeting on the RF Foil for Upgrade9 stl-file describing the foil initial block of material 5-axes milling machine

Plan for 2011 and beyond Milling of a short (in z) L-shaped box Leak rate measurement Redesign for final shape and for 4-axes milling Second short L-shaped box – At VU or at new milling machine of Nikhef Final nominal RF-box – At Nikhef (120 cm for 4-axes, 105 cm for 5-axes) Meeting on the RF Foil for Upgrade10

Backup slides More on thickness measurements Meeting on the RF Foil for Upgrade11

Discrepancies between thickness measurements of the cake foil 3D machine measures mm for top foil. Micrometer screw gauge measures 0.26 mm. Induction probe gives 0.29, 0.30 and 0.30 mm for top foil. Maybe the calibration step piece does not have the same electrical properties as the milled foil Meeting on the RF Foil for Upgrade12

Inductive thickness probe Use a standard LCR meter (HP 4267A) with the NF probe of the kit (CM-8822) T.J. Ketel

Self inductance calibration T.J. Ketel 10 kHz 20 kHz

Inductive thickness measurement Principle: Reduction of the self inductance L of a coil by the induced opposite magnetic field B EC, due to Eddy currents in a nearby conductor. At high frequency (600 MHz) the Eddy currents are only in a thin layer of order micrometers (skin effect). The change in L can be used to measure insulator thickness (example: paint) on metal with the CM-8822 kit. At medium frequency (10 kHz) the conductor thickness d and the skin depth (1 mm) are of the same order and d can be measured with LCR meter T.J. Ketel