MEG DC

1
MEG DC

1. Foils
2. Wires
3. Frames tools
4. Preamplifier
5. Gas pressure control
6. final

2

1. 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)
• ? ? framesbehavior 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 preci
  se 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
.1 mm
Reference bolts
8
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 lt 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 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.
12

• Robustness of method
• Timing information practically insensitive to
  small changes
• (f.e. Domino calibration)
• z (s10 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
Test
Milestone
Assembly
Design
Manufacturing
15
DC electronic system
At interface He bag outside Cobra
inverting
anode
Preamplifier 16 x (2 x 9) x 6 1728 channels
cathode
Non inverting
16
(No Transcript)