2/9/2004 DC status - BVR 1

1. Mechanics

2. Foil

3. Frame and Print

• Anode

• Inner cathode

• Hood

4. Pressure control + He bag + target

5. Electronic

6. Schedule

Status report on DC

2/9/2004 DC status - BVR 2

1. Mechanics

2/9/2004 DC status - BVR 3

2/9/2004 DC status - BVR 4

2. FoilOrder: a) first foil to check, 250 nm

b) send 59 others

up to now 3 iterations of a)

Geometry OK

~ +.1% vertically, ~-.1% horizontally

Third foil

larger width of the non aluminized separations between the strips

smaller size of the aluminized reference crosses

It looks like if the etching was done in 2 sequences with a shift perpendicular to the strip by roughly a fifth of the separation.

2/9/2004 DC status - BVR 5

0

2000

4000

6000

8000

10000

12000

14000

16000

0 20 40 60 80 100

Series1

Series2

0

100

200

300

400

500

600

700

800

900

0 20 40 60 80 100

length of the strip

tota

l re

sis

tan

ce o

f th

e s

trip

side 1

side 2

0

50

100

150

200

250

300

350

400

450

500

0 20 40 60 80 100

Series1

Series2

  the resistance of foil bands (~30 cm long and ~2 cm wide)

before etching [Ohm*cm] after etching [Ohm*cm]

foil2 2 .0 1.9 foil 3 1.5 > 18.0

standard aluminized Mylar foil 1.1

2 concentric electrodes (r =~1mm and 17 mm).

foil2 1.1 to 1.6 1.1 to 1.6 foil 3 .74 to 2.2 3.3 to 20 standard aluminized Mylar foil .71

1. interruptions, too thin

2. Ok ! Too thin

3. Many problems,Thicker

Resistivity

2/9/2004 DC status - BVR 6

a couloscope in nm at different positions of a sample)foil1 120, 120, 117

foil2 after: 112, 96, 70foil3 before: 188, 139, 131, 171foil3 after 255, 197, 201

Thickness

transparency

2/9/2004 DC status - BVR 7

3. Frame and Print

A) Anode1. First simultaneous use of carbon frame and print-> successful check of information

from the telegraph equation and units simulation (see later)

2. Experience about details of the procedure to built and equip anode frames

3. First iteration simulation of how the frame should be ordered to realize with mechanical tension what we finally want to have second order

4. Built in a always working Al prototype with cathode foil

5. Wires problem of other PSI groups solved

2/9/2004 DC status - BVR 8

3. Frame and Print

B) Inner cathode

c

Stretched carbon fibers(1000x d=6mm) and deformed ROHACELL

Carbon brings a factor 5-7

basis

wings

Carbon fibers

2/9/2004 DC status - BVR 9

Procedure under control

Actually at PSI last production turn to document precisely the size of deformations

PRODUCTION

Same iteration as anode

1. Good to 10-15 %

2. „linear“ matching with tension on carbon fiber wire

3. < 200 g/cm but as much as possible

Reihe1

Reihe3

-4.000

-2.000

0.000

2.000

4.000

6.000

8.000

10.000

12.000

Reihe4

Reihe5

2/9/2004 DC status - BVR 10

3. Frame and Print

C) Hood

2/9/2004 DC status - BVR 11

To do better: Stretch „vertically“ and fix the width

a) Modify the shape of the hood to have a larger flat surface to glue

b) Machine a foam structure in ROHACELL 30

c) Adapt the cathode foil procedureOnly minor modifications to the previously designed tools

Mounting of Hood foil

Largest height

Not disturbing the cell

DC report june_04,J.E.

Long design time

Long delivery time

2/9/2004 DC status - BVR 12

On the carbone fiber and foam structure

On the foil

Carbone fiber

Steel wires

On the frame

2/9/2004 DC status - BVR 13

pb

p Pa

bubbler

F0

Fi

Fo

Fo = a (p-pa) V = V0 + c (p-pb)

Fi - Fo = d(kVp)/dt =

k (dp/dt) (V0 + c (p-pb) + cp)

dp/dt ~ (Fi – a (p-pa) )/cp

a = 3 cc/(min*mbar) c = 588 cc/mbar

dp/dt = .2 mm / 10 bar

2/9/2004 DC status - BVR 14

-0.150

-0.100

-0.050

0.000

0.050

0.100

0.150

0.200

0.250

14:24 14:52 15:21 15:50 16:19 16:48 17:16 17:45

pi-pa [.1 mbar]

x left [mm]

y up [mm]

x right [mm]

gas in[cc/s]

~/20

~/2

2/9/2004 DC status - BVR 15

4. He bag + Pressure control

young positrons traverse 1 Foil

„Leaves“ space for TC

Cable duct is tight

More complicated than overall bag

2/9/2004 DC status - BVR 16

v

16x

He bag

WCHe

C2H6

He

Hermes, Belle (Openshaw,TRIUMF) + MKS

Too expensive, big size, magnetic

2/9/2004 DC status - BVR 17

v

15x

He bag

WCHe

C2H6

He

WC

1.3 g/bar on the chamber

1.7, [8.6,13.6] bar for 10 cm of He [He-ethane,Air] evt. 2 or 3 groups of chambers

~30 bar for 1m tube( radius= 2mm,1 cm**3/s of Air), 23 bar for He(50%),C2h6(50%)

Gas input in the chamber ~= 15 cm of tube with half diameter

Total gas impedance should not vary more than 20% to have healthy gas flow in all chambers

2/9/2004 DC status - BVR 18

Electronic

uncertainty on why no charge division effect seen on small prototype

-> bad matching of anode impedance on print impedance (correction out of range for print)

Program with telegraph equation and print unit simulation

Decoupling capacitor not optimized

Practically preamps survives HV breakdown of 2.1 KV ~ 3 pF

Tool ready to be used

Cables and preamps production sufficient to test correctly the Al prototype with anodes

2/9/2004 DC status - BVR 19

2.82 nF

.82 nF

Influence of decoupling capacitor

2/9/2004 DC status - BVR 20

Coming

• Test next foils …….• Test on old hood: to check principle and tools + scale of foil

deformation on pressure order Carbon Hood_0 (~7 weeks)• Last turn + Detailed measurement of elasticity and deformations of

inner cathode, final order (~ 5 weeks)• Sr-source run with DRS (not luxurious, 28 for 36 needed) of the Al-

prototype (C-anode frame + cathode foil 2) • -> confirm results of small DC for the 1:1 prototype• -> ev. Get a measured limit on the necessary cathode resistivity• 2 Russians (01/03/05 for 6 months)

2/9/2004 DC status - BVR 21

2002 2003 2004 2005

Test MilestoneAssemblyDesign Manufacturing

Full Prototype

Medium PrototypeCharge division & Cosmics

Full Detector (18 DC)

Drift Chamber

Full Prototype Beam test

Full Prototype

Charge division & Cosmics

Medium Prototype

Full Detector (18 DC)

outside insideCOBRA

Inside COBRA

Full Size Prototype

2/9/2004 DC status - BVR 22

2002 2003 2004 2005

Test MilestoneAssemblyDesign Manufacturing

Full Prototype

Medium PrototypeCharge division & Cosmics

Full Detector (18 DC)

Drift Chamber

Full Prototype Beam test

Full Prototype

Charge division & Cosmics

Medium Prototype

Full Detector (18 DC)

outside inside

COBRA

Inside COBRA

Full Size Prototype

2/9/2004 DC status - BVR 23

2005 2006

A.Hofer 1 1 1 1 1D.Fahrni 1 0.5 1 1 1L.Meier 0.5 0.5N.N.Meier 0.5 1 1 1Z.Hochmann 0.5 0.5 1Andrej K. 1 1Nicolas S. 1 1M.Schneebeli 1 1 1 1 1H.Nishiguchi 0.5 0.5 0.5 0.5 0.5M.Hildebrandt 0.5 0.5 0.5 0.5J.Egger 1 1 1 1 1

4.5 8 9 7 6