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

MEG DC

1. Foils

2. Wires

3. Frames + tools

4. Preamplifier

5. Gas pressure control

6. final

7/5/05,MEG DC,je

MEG cathode foil

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MEG cathode foil

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1. Foils june 2005 2004

7/5/05,MEG DC,je

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

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

CuBe-Drähte 50

100.0

105.0

110.0

115.0

120.0

125.0

130.0

135.0

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Nachher

Vorher2

Vorher1

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Reihe1

Reihe2

Reihe3

Reihe4

Reihe5

Reihe6

Reihe7

Reihe8

Reihe9

Reihe10

Reihe11

Reihe12

Reihe13

Reihe14

Reihe15

Reihe16

Reihe17

Reihe18

Reihe19

edge

bolts

. 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

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12.25 Kg

C fiber

C fiber + weight foil

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12.25 Kg

C fiber

C fiber + foil

Vertical displacement

Horizontal displacement

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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

209.68

209.7

209.72

209.74

209.76

209.78

209.8

209.82

209.84

209.86

209.88

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C_Fzuk

C_Fzukcor

C

F

line CF

53.24

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53.42

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point line

point+gravity

C+F

point+grav_cor

pli+grav_cor

Profile P1 in vertical position corrected by the profile in horizontal position P2

C F

C FProfile 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% C2H6

He

100 mbar

PDC

PHe

4-5 mbarPHe-PDC < 10bar

.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

.............................

9.2 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

2002 2003 2004 2005

Test MilestoneAssemblyDesign Manufacturing

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

ORLarge R

ORsmall 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

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Series1

Series2

Series3

Series4

Series5

Series6

Series7