This was Fall of 1994.
This was Fall of 1994.
The frame holds the detector and protects the box assembly from and force or stress.
The connection to the fixture is along the CG for ease of rotation and safe operation.
The down stream side or small side was where the stringing platform was installed.
Here you can see pretensioners for an area to be strung on the endplate. Springs and turnbuckles
simulated wire tension in areas which were not strung with wires.
After sector ZERO was strung, the stringers began working on the real detectors.
This is sector ZERO again showing the tensioner cable for the area not strung with wires.
Extension springs were used along with turnbuckles to simulate the tesion of the missing wires.
Each spring simulates the tension of 56 wires or ~12 lbs.
Pretensioner devices are used to adjust endplate deflection and wire tensions constant.
Helmholtz coils, magnets, were made in a curved shape to fit close to the wires.
A counterweighted engine hoist was used on the downstream side or the stringer side.
The other coil was attached with rollers onto the stringing platform.
A team of 4 stringers work at the same time in very close proximity.
Two stringing machine operators on the platform and 2 stringers on the floor
to catch and tension the wires.
I designed very ridged articulating booms for stable support of the stringing machines.
I will add descriptions later when time is available
The stringing machines had to be a low profile design and then mounted at the ceiling level in order
to string certain part of the detector due to the low ceiling height.
The stringing platform was adjustable in height. This was raised or lowered
to the required height using the chain hoists and then pinned in place and locked down for stability.
The Helmholtz coils were water cooled. Mylar sheet, 0.01 inches thick was used to protect
the wires during stringing.
After the detectors were strung and tested, the gas bag, thin windows, were installed.
The small angle wires required the max platform height. The stringer catcher tensioner had to use a
mobile work platform to position themselves for stringing.
The pulley must be adjusted such that the wire is perpindicular to the endplate
in order to properly tension the wire.
Clean room garb is standard so the temps must be kept cool to keep the workers cool.
Stringing machines are operated shoulder to shoulder. Wires are strung, pins are
threaded and crimped in close quarters.
Window installation was a huge challenge. With only an inch between
the wires and aluminum posts, it was slow going working the window.
Just one slip and disaster, damaged wires. The R2 windows were one of the most time intensive aspects of these detectors.
A mechanical bracket with soft rubber was used to support the window.
Not much space was left for a tape seal.
The last minute keep out zone for R1 required severe angles in the gas bag ends and corners.
This produced many many wrinkles making a gas tight seal impossible.
and sealing problems.
Here you can see just how close the wires are to the window
The design staff limited us to 3/8 inch distance from the endplate for the exh connections.
The stecilite material eliminated the need for an insulated standoff. The metal trumpets were
placed in the endplate holes along with a centering sleave. The wires are clearly visible.
This is a nice illustration of the wire/window gap.
The lighting angle must be just right to see the wires. The reflections of the flash are clearly visable.
Compound angles were hard to seal.
All the window components had to be pre fit, pre cut, and numbered by hand before the window could be installed.
Flamible gas detectors were used to locate leaks.
Sealing the gas bags required several iterations. Final sealing was done after removal from the stringing
fixture to maximize stringing time. The bag had to be good enough to fix without breaking the seal.
Copper tape was used to electrically connect the windows with the ground plane.
The seal at the nose, large angle side was an easy one.
The window was installed from the back plate to the nose. It had to be thread between the wires
and the posts the entire way. No wires were broken during this process.
The tighter you try and make the bag, the more pronounced the wrinkles become.
Because of the keep out zone, six 1/4" lines exited the detector on each side. These 6 lines
entered another adaper mto become two 1/2 ich lines. The four 1.2 inch lines then came together
into a single line. This line size was increased to 1 inch when it was installed into the torus.
the upstream face of the bag was much more complicated than the other. The wires on this side were
much closer to the bag due to the angle.
Once the window is stretched out between the wires and posts, it is clamped starting
in the middle and moving out toward both ends.
The tape seams were used to keep the window aligned as much as possible.
Both sides of the window must be worked on and in both directions iteratively.
The sharp edges and corners of the post mounting bloks had to be covered in tape to prevent
damage to the window. Copper tape busses were run along the edge of the endplate to ground
the aluminum side of the window to
The posts and diagonal struts made window work very difficult and time consuming.
Window installation ate up way too much stringing time. Window sealing also diverted too many resources.
R2 windows likely ate up at least a man year during the stringing effort.
The R2 upstream window was much more problematic than the downstream one.
The aluminized side of the window had to be grounded to prevent static charge buldup.
Great care had to be taken as not to isolate and part of the window by cutting and repair.
The windows ended up loose and wrinkled until they are inflated.
Another ground connection.
More window work.
Once the window is on, then it must be sealed with tape
Cuts had to be made to remove excell material in the upstream window back plate corners.
Once inflated, the bags puffed out way more than expected.
Here you can see the sharp edges and corners on the post block.
Extra support had to be added to permit R1 insertion into the magnet bore.
plastic and foam had to be taped on the post blocks and post components to protect
the window from shart corners and edges.
Certain locations added to the difficulty of sealing the bag. The post blocks,
torus mounting holes, and corners are examples of there problematic locations.
Eventually each sector gets it own gas bottle and pressure protection bubbler.
R2 was also strung in the EEL clean room at JLAB.
R2 started late but had to be done first. This required an additional effort.
Wheels were installed and the detector was rolled out of the stringing clean room
and into the instrumentation area.
We had to make special low profile adapters to connect the gas lines withing the keep out area.
The gas supply flowed into the detector next to the nose plate.
The field and guard wire layers are wire wrapped into HV segments.
Each sense wire has an individual connection on each STB and HV board.
The negative high voltafe field wire layers are wire wrapped away from the sense wires.
You can see the old stype paper survey targets on the endplate.
The sector strung at JLAB were also instrumented at JLAB.
All the sectors from ODU were left at ODU until it was time to install them.
Mounting hardware for the PC boards was glued on. The boards had to be aligned
and held on with tape until the epoxy cured.
Sector
Here you can see a completed R2, R3, and a R2 on the stringing fixture.
The EEL contained all 6 R3 detectors as well as 2 R2 sectors.
Sectors were stored in the clean room one strung.
Mounting hardware for the PC boards was glued on. The boards had to be aligned
and held on with tape until the epoxy cured.
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