status report meg dc 13/2/2006
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1
Status report MEG DC 13/2/2006
1. Foil, cathode, hood, anode
2. DC1tests and measurements
3. Preamplifiers
4. Cables, connectors, cable panels, splitter + sum
5. Cable duct, DC support, minibag
6. Tests and Schedule
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( ¦measured¦ - ¦planed¦ )/ ¦planed¦
-0.0025
-0.002
-0.0015
-0.001
-0.0005
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0 10 20 30 40 50 60 70
-170
170
-23.4
-104.3
18.9
99.8
length scale
All Foils delivered : resistance tested by REPIC : geometry checked
New polyimide: UPILEX stronger, less sensitive to humidity
3
Cathode : delivered after some discussion about planarity
Hood: first 2 delivered for check, OK given for the 16 others
Anode: delivered
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DC1 ASSEMBLED
.1 mm precision to frame reference points reached for anode, cathode and hood
5
DC1 ASSEMBLED
1. Production and mounting stopped to check HV-print-C edge stability
(go to DC2)
foil measurement epoxided C-fiber mount cathode test Hood first delivery + mount
Simple HV test, HV-preamp test, set start value of parameters ( potential wire Voltage, ..)
(go to DC2)
Read out(go to DC2)
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a) For sudden change (door, ..)
no change in pV (flow in = flow out) 2 mbar in He bag .2% in pressure compensated by .2% in Volume = .1 mm
= 1. Pa in (He bag-DC)
b) For change over 2 mbar at the rate of storm for 20 l ~ 2.6 cc/sec flow controller (DAC) 1 Hz correction per second < 1 Pa = .2 cc/secMKS 1179B at 200 sccm precise to .7% = .025 cc/sec
c) Diff. Pressure to be controlled < 1 Pawith range of 1 mbar, MKS 120AD .25% .25 Pa
More direct measurement to determine necessary pressure stability :
• Gas outlet of DC in simple bag with same tubes as to manifold
• source at a fix point in the middle of the surface
• Vary flux through the chamber (0 to 50 sccm) 0 to 3 Pa and measure amplification variation with the current in the chamber
CONFIRM DIRECT MEASUREMENT OF CHAMBER „EXPANSION“
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50% He + 50% C2H6
He
>1.8 bar
PDCPHe
< 500 Pa
To Air
PHe-PDC < 1Pa
.2 Cc, 14 Cc
1400 l
DC 16 x 1l
Flush in ~2 h ~ 150 sccm
Storm ~ 500 Pa in/10 min = 8 Cc/min
5. Gas pressure control
pump.0 to .2 bar
Dif. Pressure sensor
Flow controller
Flow controller
8
Preamplifier cooling (Malte)
Some like it not hot and water cooled !!
Preamplifiers :
With 6 V supply and 5 V regulator on the preamp chip
input protection diode for 2.2 kV break down
~ 100, with old dimensions
~ 150, ~1.5 mm shorter and inclined connectors (5 different types)
production continues
Last prints and elements partly here, connectors offered with cables
Tests with DRS and DC1 + DC_Al + small DC factor 2 ?
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Cables, connectors, cable panels, splitter + sum
1750 between ~250 cm and ~400 cm + 1750 ~750 cm long
Precimation coaxial as in magnet , offered
Suhner coaxial soldered on 16 channel print, attenuation + ~6 db
Erni 34x2 pins (SMD?) connectors for 16 channels
Splitter (1 k) + ampli
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Background in LXe from central part of cable duct (Hajime,..)
Distance to current position [cm]
number of background event (low threshold)
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Measurement by survey group of exact edge shape at COBRA’s smaller radius ( being analyzed)
Later measure welding circle at transition [edge – inner Cylinder] ( fix shape of DC Al fixing parts)
To larger radius
Small level arm (near TC)
12
minibag
1. Non negligible effect on DC precision because of additional multiple scattering
2. Effect smaller near the target or near the DC both technically dangerous
3. Minibag is designed and will be constructed as test bag for:
• tests with a few DC
• Study of foil mechanical resistance
13
DC tests
a) HV test with assembled DC : [anode prints, parameters for pressure behavior]
b) HV test with preamps and DRS with Sr90 and cosmics:[ preamps, DRS,..]
c) 6-11 April : test in 1 with minimal ionizing (>150 MeV/c) or e 50 MeV/c) 1 DC + Al-DC
[preamp, DRS, DC calibration, resolution,…]
d) 11-16(24) May : test in Cobra, Field on + e+beam with < 3 DC’s[DC behavior in Cobra background , 511 keV]
e) Eventually second test in pE1 with more DC [ better DC calibration]
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15
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Person jan.-mar. 2006 apr.-jun. 2006
Johny 100% 100% Malte 90% 80% Andi 100% 100% Dieter 100% 100% Florian 100% 100% Matthias 40% 40% Hajime 60% 60% Zdenek 40% 40% Ueli 30% 30% ------ ------ 6.6 6.5
Manpower
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