Talk:GTS meeting 1 12 16

• Phil gave an update on the item list for the multi-alkali chamber:
  • He has marked the position of the gun table
  • Instead of deisgning a support for the puck fork and making new pucks with grooves, we will go with standard pucks and use the standrad "puck holder" attached to the rotary
  • We asked John to design/build a motor stage for the bottom manipulator
  • We discussed with Marcy about the RGA sensitivity since its factory designed length nipple needs to be shortened to allow the cage being inside the deposition chamber. The issue is that the nipple welded to the depo chamber is longer than that in the depo chamber that Mamun uses. See below:
  • Hi Phil and Matt - we should be ok with the RGA. Gerardo (now at MKS) worked at SRS on the RGA. We may lose some very high mass reading, but Cs is likely fine.
  • Marcy: One other thing: would a quad mass spec, such as perhaps an SRS RGA, work if we need to put the grid in the chamber and doing so leaves the conflat joint in the middle of the rods? We don't care much about relative calibration or such, but want a device that we can make sure that high AMU elements (like Cs) are being deposited at reproducible rates. Would a joint completely disable the utility, or just make it less sensitive or calibrated?
  • Gerardo: This one is easy to answer. If you use a half length nipple all you will compromise is the upper operating mass range of the device. In other words, if you use a 200 amyu unit you might get a message that says you can only run up to 190 amu instead of 200. This is because changing the envelope around the rods changes its capacitance, and that affects the resonance between the rods and the high Q oscillator circuit used to pump RF into the rods. If the rod capacitance to the walls changes too much, the resonator is unable to pump enogh RF at the highest mass values. Good news: the software will tell you how high you ca trust the unit in mass, and until that mass everything is fine..i.e.you will not notice a difference.

• Magnetized beam:
  • The power supply for the big solenoid will be placed where the FEL THz chicane PS is, where there is power and water. The output will be wired up from the FEL vault to the GTS.
  • Riad mentions that the PS will likely be one of the ARC6-ARC9 power supplies (320 Amps, 830 Volts).
  • Riad to schedule a meeting with Vashek and source group to follow up on radiation shielding calculations.

• Yan presented the electrostatic design for the shed to be used with a black (partially conductive) R30 insulator in the ITF gun. The optimization of the shed is based on John's original design which demonstrated 375 kV with a white R30 insulator, and the one that is currently installed in the GTS gun with a ball cathode & puck. Yan's design lowers the maximum field from 12 to about 10 MV/m at 350kV, and has negligible field at the triple point junction.
  • John H. will be doing the mechanical design for this optimized shed.

• Beamline
  • we discussed action items and started to lay down the tasks on a schedule.
  • Carlos will the input from the meeting and generate a schedule and also an ATList to request support from EES and I&C
  • The two solenoids have been measured at magnet test by Mike Beck and Yan brought them over to the GTS.
  • Phil mentioned that he will use sections of the 80/20 frame already in the GTS to extend the exisiting 80/20 VA beamline girder for the dump
  • Counting from upstream to downstream, and after the last solenoid, we need: 1- DP can, cross with viewer, and beam dump.
  • Carlos to contact Joe Gubeli and ask for DP can.
  • The viewer cross in in the GTS mezzanine on the wooden bench.

• Drive Laser transport
  • Shukui gave a summary of the layout for the optical transport and cost estimate for components needed to upgrade the optical transport.
  • Earlier in the morning, Phil, Shukui and Carlos discussed the position of two new mirror boxes to be anchored to the ceiling for updating the drive laser transport.