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

2

( ¦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

4

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“

7

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 ?

9

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

10

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)

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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

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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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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