The n-³He Experiment at SNS : Ion Chamber

Work package manager: Michael Gericke

Related Pages:

Approved Lifting Plan 11/3/2014: Ion Chamber 103014-ORNL-544-092013-Ordinary Lift Plan.pdf

Pin Map for Chamber (pdf)

Chamber Installed:

On 11/06/2014 the target was lifted into place on the 4 point stand:

See the Installation page for more details of the lift process.

n3He chamber CAD Model Showing Feed Throughs	Image of n3HeChamber Housing:
Frame Stack Bottom side with Teflon Shielding Over Traces	Top Side - no teflon shielding

Chamber Details:

• 2 HV Feed Thrus
• 4 Signal Feed Thrus (Shown above with 2 x 25 pin flanges Lesker Part number IFDGG251056X
• 2 Gas feed Thrus with a 90 degree elbow

Wire Planes:

• 33 wire planes
• Macor Ceramic Material
• Metallization used to apply conductive solderable traces
• 16 signal planes with 9 wires
  • 
    
• 17 HV planes with 8 wires
  • Traces in HV frame are joined left to right for voltage distribution
  • 6 guard rings are around each of the three possible three point mount positions to drain leakage current to ground before reaching signal plane
• 1.9 cm wire spacing between like wire planes (signal to signal or HV to HV)
  • 0.95 cm between nearest planes (signal to HV)
• 1.9 cm spacing of wires in the planes

Signal Frame Drawing	HV Frame Drawing

Signal and HV Frame Image

Left hand frame is a Signal frame. The right hand frame is a HV frame.

Fill Gas

• He-3 to approximately 1 atmosphere
• Possible addition of nitrogen

Signal Readout

• 144 signal wires
• 4 feed throughs
  • 36 signal wires per feed through
• 2 plugs per feed thru
  • 18 signal wires per plug
• each plug has two cables on the back
  • 10 and 15 wires on the cables
  • 9 wires per cable to be used

Vacuum Side 25 pin Plug. PEEK with capton insulated wires. (Lesker Part No FTAK2512P))

Vacuum Side 25 pin Plug. PEEK with capton insulated wires. (Lesker Part No FTAK2512P))

eLog Entries:

During the testing construction and assembly of the target chamber a number entries were made in the n3He electronic log book.
The following entries in the eLog are related to the target chamber:

• 6: Wire Frame Stringing
• 7: Wire frame Stringing Progression
• 13: Leak Checking Target Chamber
• 14: Leak Checking after Weekend Bake
• 15: Leak Checking after Welding
• 16: Frame Stack Assembly pt. 1
• 17: Frame Stack Assembly pt. 2
• 18: Soldering First PCB to Frame Stack
• 19: Soldering Second Ground and First Signal PCB
• 20: Soldering PCBs
• 21: Soldering Ribbon Cable
• 22: Soldering Ribbon Cable
• 25: Survey and Alignment Frame Stack Measurements
• 26: Soldering HV PCBs
• 27: Adding Shielding to PCBs
• 28 Lifting Frame Stack into Housing
• 29: Initial HV Test
• 30: Signal Wire Verification and Layout
• 31: Sealing Flanges

Teleconference Results:

9/25/13 Teleconf

Mark:
- pieces coming out from machine shop
- chamber assembly at the end of year
- alignment under consideration
- Mark provides data for Josh to be added to the 3-D model
- Agreed an alignment meeting during DNP
- for winding Chris C. provides an optical table, winding can start after DNP

10/2/2013 Teleconf

Mark:
- working on supports to lift the wire fame assembly into the vacuum housing safely one it is assembled
- will come to ORNL Oct 27th -- Kabir will transport optical table before then

11/6/2013 Teleconf

- Chamber shipment arriving at any dat
- Mark is working towards getting ready for wiring the frames, he needs some formal procedures
he will produced some 30-40 gallons of dirty alcohol that needs to be properly disposed
- Seppo is looking at option - if it comes to that - that during run we need to replace 3He gas. How can be it done;
possibility at lab, outside but at US, or we need to ship chamber back to Canada.
- Seppo is also looking at the gas manifold requirement and do we have it

12/04/2013 Teleconf

- mark wired 27 frames out of 37, 10 to go
- also ultra sonic cleaning in process - after learning to do it properly
- PCB boards arriving in mid Jan
- after having PCB board mark can start stacking
- prio mid Jan chamber will be closed, leak checked and pumped with slight heat and then filled with pure he-4
- Tritium issue is brought up with SNS rad safety people
-

2014/08/13 Meting Presenation:

n3He-NewWireFrame r2.pdf
2014/09/12 - Magnetif Field Measurements
magData-TargetChamber - 2014_09_12.xlsx

Probing The Hadronic Weak Interaction