2/9/2004DC status - BVR1 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

2/9/2004DC status - BVR2 1.Mechanics

2/9/2004DC status - BVR3

2/9/2004DC status - BVR4 2. Foil Order: 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.

2/9/2004DC status - BVR5  the resistance of foil bands (~30 cm long and ~2 cm wide) before etching [Ohm*cm] after etching [Ohm*cm] foil foil > 18.0 standard aluminized Mylar foil concentric electrodes (r =~1mm and 17 mm). foil2 1.1 to to 1.6 foil 3.74 to to 20 standard aluminized Mylar foil.71  1.interruptions, too thin 2.Ok ! Too thin 3.Many problems,Thicker Resistivity

2/9/2004DC status - BVR6 a couloscope in nm at different positions of a sample) foil1 120, 120, 117 foil2 after:112, 96, 70 foil3 before:188, 139, 131, 171 foil3 after255, 197, 201 Thickness transparency

2/9/2004DC status - BVR7 3. Frame and Print A) Anode 1.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

2/9/2004DC status - BVR8 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

2/9/2004DC status - BVR9 Procedure under control Actually at PSI last production turn to document precisely the size of deformations  PRODUCTION Same iteration as anode 1.Good to % 2.„linear“ matching with tension on carbon fiber wire 3.< 200 g/cm but as much as possible

2/9/2004DC status - BVR10 3. Frame and Print C) Hood

2/9/2004DC status - BVR11 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 procedure Only 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

2/9/2004DC status - BVR12 On the carbone fiber and foam structure On the foil Carbone fiber Steel wires On the frame

2/9/2004DC status - BVR13 pbpb pPaPa bubbler F0F0 FiFi FoFo F o = a (p-p a ) V = V 0 + c (p-p b ) F i - F o = d(kVp)/dt = k (dp/dt) (V 0 + c (p-p b ) + cp) dp/dt ~ (F i – a (p-p a ) )/cp a = 3 cc/(min*mbar) c = 588 cc/mbar dp/dt =.2 mm / 10  bar

2/9/2004DC status - BVR14 ~/20 ~/2

2/9/2004DC status - BVR15 4. He bag + Pressure control young positrons traverse 1 Foil „Leaves“ space for TC Cable duct is tight More complicated than overall bag

2/9/2004DC status - BVR16 v 16x He bag WC He C 2 H 6 He Hermes, Belle (Openshaw,TRIUMF) + MKS Too expensive, big size, magnetic

2/9/2004DC status - BVR17 v 15x He bag WC He C 2 H 6 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%),C 2 h 6 (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

2/9/2004DC status - BVR18 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

2/9/2004DC status - BVR nF.82 nF Influence of decoupling capacitor

2/9/2004DC status - BVR20 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)

2/9/2004DC status - BVR Test Milestone AssemblyDesignManufacturing 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

2/9/2004DC status - BVR Test Milestone AssemblyDesignManufacturing 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

2/9/2004DC status - BVR23