The top mounting plate can be positioned whenever the techs come to do it. The machining and materials from UVA have arrived and are ready. This includes the bottom target tri-winged frame and the new aluminum feet holders. The threaded feet are also finished from FNAL. The dowel pins should be done soon. After this the lifter frame should go in and then the magnet can in principle go into position. In order for us to be ready for that we want new PTFE seals which are more radiation resistant. We need to clean and prep the magnet and can, and to do the dock survey.
(See below for survey info)
| Do Immediately | Additional Information |
|---|---|
Fridge sensors | 1KOhm Ruthenium Oxide |
| Determine and measure true path for all cables coming from target cave and order all cable needed | Front Penetration → Racks on Cryo platform → Counting House Side Penetration → Racks on Cryo platform → Counting House |
| Liquid Helium Level Probe mounting clips | Being made at UVa - 7/17/19 |
| Replace Black BUNA-N O-rings | Measure existing O-rings and find PTFE (Teflon) equivalents
|
Make and test indium seal on shell/nose also setup safety walk through for testing stand vacuum vessel | Setup Operational Readiness Clearance (through Rick) |
| After replacing seals setup safety walk through with | Setup Operational Readiness Clearance (through Rick) |
| Buy a flaring tool for copper tubing | |
| Assemble and test microwave system | Needs to be shipped from UVa - 7/17/19 Borrow gore cable from UVa Need waveguide too |
| Get Liverpool NMR Q-meter (and ancillary equipment) from LANL | |
| Once EIO arrives, connect EIP and test air core cable | |
| Setup sensors on stick | Check with lakeshore |
| Stink test in the target loading area | with "special" spray |
| Setup and test manometer | |
| Setup external magnet sensors with data going into slow controls data stream | |
| Shim Microwave actuator bushings for hard stop and top target. Microwave table and magnet should be in place and use the information from initial survey to measure |
| Things to do when not working on the immediate things | Additional Information |
|---|---|
| Setup Target Rack | Stepper motor drives and power supplies ADC for position readbacks Microwave EIP Lakeshore 218 x2 Level Probe Readout Turbo readout and Controller IV gauge readout Teledyne Hastings readout 4He & 3He manometers Possibly Microwave Power Supply Target Insert Lakeshore Fridge Lakeshore External Magnet Lakeshore
|
| Get hoses for microwave (EIO) | Either hard plastic or rubber |
| Target Controls Computer | Josh will find it |
| All cabling from target to racks and counting house | need lengths and to order cables |
| setup target operator station | |
| setup target loading station | |
| Finalize NMR | testing still needed |
| Target handler and alarm system | |
| Setup NMR VI | |
| Annealing controls | |
| Setup and test Main Gate Valve | |
| Test Air-core cable with EIP/microwave | |
| Setup Insert and leak check and electronics check, sensors, coils, SMA | |
| Setup Nuc and oscilloscope and PDP | |
| Setup Roots stack controller and power | |
| Get some plastic tubs and foam dewars |
For SpinQuest it will be difficult to get the positioning of the target perfectly aligned with the beam. This is because all fiducials that we can get while the system is warm and open will change once we are running with liquid helium. We have X, Y positioning measured from averaged vertex reconstruction but this takes at least 1 month of data to produce, and this will only give the mean with a very large variance. This means we need to get the information we need from the survey and the final set of surveys will need to contain some cold target information. The precision in the target cell to beamline positioning needs to be good to mitigate large absolute errors while running. This is estimated to be on the sub-millimeter level (based on simulations being confirmed). There are several factors that can lead to false asymmetries relating to this precision. There can be a bias produced in the detector if there the beam is off center. There can be less polarized scattering if the beam is not aligned and missing part of the target (beam profile dependent, also being checked). There can be greater scattering off the aluminum ladder on one side as compared to the other. Most of these manifest from X being off but if Y is off over 1 mm then the same issues start to manifest with the ladder as well but this may not result in false asymmetry and only result in additional heat load to the coils. During our discussions with the survey crew it was suggested to install transparent windows so we could do an optical survey on the magnet and target cells while cold. This would be great to do but I do not think this is possible at FNAL. I don't believe we would ever pass a safety review to do that. The next best option is to do surveys using liquid nitrogen. We could calculate the level of contraction for both LN2 and LHe. We can then measure the contraction during an open system survey with LN2 in the magnet and in a nose with a window on it. The set of survey would go like this:
1.) Survey on dock with fully open system (no nose, no nitrogen shield, no beam windows). Survey the magnet aperture, the target insert along X only, and the outside fiducials (can and top flange). The primary goal of this survey is to generate fiducials on the can and top flange to help align when going into position in the cave. This part of the survey should be able to be measured with error at less than 0.5 mm. The fiducial on the can is meant to use to align the top and bottom to our best precision. The tolerance of the drawings is 0.5 mm. Use the leveling pads to level the magnet on the dock before survey. This survey can be use to check the variation when leveled and re-leveled or if the magnet is plumb not the top flange is slightly off level. Working on the dock for this survey will have the advantage of space unlike in the cave. We can also flip the insert and check target cell up stream and down stream differences.
2.) Survey in cave using LN2 in nose and magnet. This would be a partly open survey with a special nose put on with transparent windows on either side for optical survey. The nitrogen shield and beam widows on the vacuum are left off for this. This survey in the cave will be of the magnet aperture, the target insert along X, Y, Z, and the outside fiducials (can and top flange and reference locations in the cave). Crosshairs will be use in the front and back of the target cell to help determine degree of twisting in the cell. Cross hairs in the can windows can also be use to set the rotational alignment of the can. The target insert carbon fiber is not expected to contract very much but the aluminum ladder can. The primary goal of this survey is to compare to calculations of contraction and measure positioning of target cell with respects to magnet aperture and also with respect to the beamline. There should be a hard stop setup on the actuator that positions the top target exactly in the beam line (to test repeatability of the string potentiometer and gears). We also need to take the stick out and few times and test the scale of deviation in reproducibility in target cell shifts and bends. This will take two surveys to do since we will need to machine the piece for this hard stop after this first cold survey measurement. In order to do this the actuator and motor should be installed so we can move up and down with reasonable repeatability. This repeatability can also be tested during this survey. The drawings indicate a change of 4.5 mm up when cold.
3.) Put in hard stops and re-survey. This will be adding a shim to the hard stop that already exists. Here we can have the goal of .25 mm target centering in X,Y and measure a set of cells using cross hairs in Z.
4.) An X-ray survey while cold would be the next step if possible. We may not needed it if we achieve good results from the first 3. It may also be possible to use phosphine graph paper to check beam position on a special target insert without depending on the magnet or nose having LHe in them. Or use something that discolors or burns in the beam so we can make an insert that will be use over the experiment to check position.