7/5/05,MEG DC,je MEG DC 1.Foils 2.Wires 3.Frames + tools 4.Preamplifier 5.Gas pressure control 6.final

7/5/05,MEG DC,je 1.Foils june

7/5/05,MEG DC,je 2.Wires Anodes Goodfellow, Nickel/Chromium wire (Ni80/Cr20), NI mm, temper hard 50 g (~8 mm) Potentials Leoni Temco, Beryllium Copper wire (Cu98/Be2), BSEN12166x mm, temper hard  110 g (~5.5 mm)  Good to prepare, solder and position

7/5/05,MEG DC,je 3. Frames and tools Iteration: first values for elasticity and behavior  calculate shape  order [done] Delivery of first prototypes : cathode and anodes, hood (in 2-3 weeks) Detail measurements of geometry during construction procedure to go to final values and to check tools   ( foils geometry is good, free frame precision)   frames:behavior with the different forces set during procedure  new values for elasticity and behavior  calculate shape  final order  anode : behavior of wires and with wires, prints and tools  cathode : small corrections to tool  final correction  order  hood : imprecision in tool and weight deformation precise measurement in PSI workshop of the tool  order to workshop to redrill foil reference holes   construction : training of procedure, document final procedure, organize construction route

7/5/05,MEG DC,je Anode. 1 mm Print reference point Wire points (precision) Frame edge points (DC stability) Reproducibility of wire tension

7/5/05,MEG DC,je Cathode frame Vertical displacement Horizontal displacement

7/5/05,MEG DC,je Vertical position of peaks along cathode strips on both sides.1 mm Reference bolts u1 u2 d1 d2

7/5/05,MEG DC,je Profile P1 in vertical position corrected by the profile in horizontal position P2 CF CF Profile P1 in vertical position Line C-F Coordinate system of the central plate Fit of P1-P2 adjusted to line C-F,with foil reference points

7/5/05,MEG DC,je 4. Preamplifier : modify input  survive DC HV breakdown 5V supply : supply 6 V and regulate to 5 V   less sensitive to „noice“ inducing oscillations check of possibility to play with electronic amplification factor   signal to ratio stays constant  domino range, gas amplification, preamp stability

7/5/05,MEG DC,je 50% He + 50% C 2 H 6 He 100 mbar P DC P He 4-5 mbar P He- P DC < 10  bar .2 cc, 14 cc 1400 l 16 x 1l Flush in 3 h ~ 100 cc/min Storm ~ 5 mbar/10 min = 8 cc/min 5. Gas pressure control

7/5/05,MEG DC,je Dr. Arnd Gusovius Bronkhorst (Schweiz) AG Wait until new hood frame and measure new pressure sensitivity of geometry Precision planar drift chambers and cradle for the TWIST muon decay spectrometer R.S. Henderson, Yu.I. Davydov, W. Faszer, D.D. Koetke, L.V. Miasoedovb, R. Openshaw, M.A. Quraan, J. Schaapman, V. Selivanov, G. Sheffer, T.D.S. Stanislaus, V. Torokhov Pressure control A significant challenge for the gas system design was to maintain the external cathode foils as.at as possible and with a positional stability of ±50 µm or less The DC operating total capacity of 16.5 cc/mTorr implies an average foil deflection rate of 11.6 µm/mTorr, which requires a differential pressure stability of ±4.3 mTorr to maintain foil position stability of ±50 µm.

7/5/05,MEG DC,je Robustness of method Timing information practically insensitive to „small“ changes (f.e. Domino calibration) z (  =10 mm, Charge division) and precise z (4 cathodes) Informations contained in ratio of signal integrals parameters mainly sensitive to changes modifiing the signal to noice ratio small for common shift in calibration preamp amplification ( measured for factor 2)

7/5/05,MEG DC,je gas pressure control with C-hood complete resolution test (64 channels) (Al-prototype if necessary) 300 Watt test, Al- or C-full-prototype, with beam (and magnetic field,511 KeV)

7/5/05,MEG DC,je Test Milestone AssemblyDesignManufacturing Drift Chamber Full Prototype Charge division & Cosmics Medium Prototype Full Detector (18 DC) outside inside COBRA Inside COBRA Full Size Prototype Full Prototype Charge division & Cosmics Medium Prototype Full Detector (18 DC) outside inside Inside COBRA Full Size Prototype

7/5/05,MEG DC,je anode cathode right left up + up - down + down - 16 ch. Cable To sampling Or from left OR Large R OR small R DC electronic system Preamplifier 16 x (2 x 9) x 6 = 1728 channels inverting Non inverting At interface He bag – outside Cobra

7/5/05,MEG DC,je