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MEG DC

MEG DC. Foils Wires Frames + tools Preamplifier Gas pressure control final. Foils june 2005 2004. 2. Wires Anodes Goodfellow, Nickel/Chromium wire (Ni80/Cr20), NI055110 0.025mm, temper hard 50 g (~8 mm) Potentials

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MEG DC

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  1. MEG DC • Foils • Wires • Frames + tools • Preamplifier • Gas pressure control • final

  2. Foils june 2005 2004

  3. 2. Wires • Anodes • Goodfellow, Nickel/Chromium wire (Ni80/Cr20), NI055110 0.025mm, temper hard • 50 g (~8 mm) • Potentials • Leoni Temco, Beryllium Copper wire (Cu98/Be2), BSEN12166x2 0.050mm, temper hard •  110 g (~5.5 mm) •  Good to prepare, solder and position

  4. 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

  5. Anode Wire points (precision) Frame edge points (DC stability) Print reference point . 1 mm Reproducibility of wire tension

  6. Vertical displacement Cathode frame Horizontal displacement

  7. Vertical position of peaks along cathode strips on both sides u1 u2 d1d2 .1 mm Reference bolts

  8. C F C F Profile P1 in vertical position Profile P1 in vertical position corrected by the profile in horizontal position P2 Line C-F Fit of P1-P2 adjusted to line C-F,with foil reference points Coordinate system of the central plate

  9. 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

  10. 5. Gas pressure control He PHe 1400 l 16 x 1l 50% He + 50% C2H6 PDC Flush in 3 h ~ 100 cc/min Storm ~ 5 mbar/10 min = 8 cc/min 100 mbar 4-5 mbar PHe-PDC < 10mbar  .2 cc, 14 cc

  11. Dr. Arnd Gusovius Bronkhorst (Schweiz) AG Wait until new hood frame and measure new pressure sensitivity of geometry Precision planar drift chambers and cradle forthe 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 ............................. 9.2 Pressure control A significant challenge for the gas system design was to maintain the externalcathode foils as .at as possible and with a positional stability of ±50 µmor 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 stabilityof ±4.3 mTorr to maintain foil position stability of ±50 µm.

  12. Robustness of method • Timing information practically insensitive to „small“ changes (f.e. Domino calibration) • z (s=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)

  13. 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)

  14. Drift Chamber 2002 2003 2004 2005 Charge division & Cosmics Medium Prototype Full Size Prototype outside Full Prototype inside Full Detector (18 DC) Inside COBRA Medium Prototype Charge division & Cosmics COBRA Full Size Prototype inside outside Full Prototype Full Detector (18 DC) Inside COBRA Design Manufacturing Assembly Test Milestone

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

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