Minutes of meeting held on 02 Jul 2020
==========================

slides are at:
https://beamdocs.fnal.gov/AD-public/DocDB/ShowDocument?docid=8539

(1)  Dave C. gave a talk about the preparation for the 20 Hz test:
     (i) Boot new code into real TLG for the regular test.
     (ii) For the test system: UCD-t system, it only exists in the Mac
     Room.
     (iii) Try to test in middle of Sept.
     (iv) People should be careful to turn off PS to not run at 20 Hz.
     (iv) People will be warned and should ID systems that will be
     affected.
     (v) During the test, we just ahead to use the timelines in 20Hz.
     (vi) Bill is there a timeline for NOVA alone? Dave says 1.2s is
     the fastest. There's not enough money for RF and main bus. PIPII
     RF upgrade only  gives more power for beam loading. Not enough to
     go faster ramp because there's not enough RF volts. That's why we
     are stuck at 1.2 s. More volts => more RF cavities.

(2) Chandra gave a talk on the longitudinal dynamics at injection from
data that he had collected:
     (i) There are 3 areas of loss. Injection, transition and
     extraction.
     (ii) 4.3e12 efficiency is 95%.
     (iii) Mitigate losses. Understand where the loss comes from.
     (iv) 0.1% at transition. Look at power loss.
     (v) Goal is to have losses < 500W in 700 kW, 900 kW and 1.2 MW
     era.
	(a) requires 94% efficiency for PIP
	(b) 96% for 900 kW
	(c) 98% in PIPII. Very close to momentum acceptance of
     Booster. 
    (vi) Very important to mitigate emittance dilution and beam loss for
     the entire cycle. Especially at the early part of the cycle.
     (vii) Chandra showed the intensity and bunch length for first 10
     ms.  B:IRMCHG (CHG0)says that there is 5-6% beam loss. But wall
     current monitor  indicates < 2% beam loss. Is there an instrumentation error.
        (a) Bill says that we cannot use chg0 (toroid) to that level
	of accuracy.
	(b) To calibrate chg0 Bill suggests using the laser notcher to
        kick out a bunch to check out the calibration of CHG0.
        (c) We may use TLMs but they are only sensitive to vertical
	losses.
	(d) PIPII DCCT will be coming > 2022.
    (viii) The neck is presently used for optimizing capture. Work on
    understanding the neck gave the following: 
        (a) ID'd large phase advance errors in the RF cavities that we
	have corrected
	(b) led to digital paraphase system that will be fully
	commissioned  when beam comes back.
   (ix) Chandra noted that prior to 2018 shutdown, 6.3e12 can be
   adiabatically captured with no neck and 94% efficiency
    (x) After 2018 shutdown: beam adiabatic capture was not as efficient
      as with neck.
      	 (a) As soon as the LLRF feedback turned on, about 250
      us. There seems to be a phase dip in the RF. Suspicion is that
      there is a LLRF problem that happened in 2018.
         (b) Craig says that in 2018the old RPOS phase shifter was replaced. Started
      running the RPOS with the DDS card in the LLRF controller. There maybe
      electronic offsets, even if the gain is zero, when the feedback
      is turned on, it may yank the beam.
         (c) Bill suggests that Brian set up a test measurement, to
	 slowly turn  it on and off rather than to suddenly turn on to
	 see whether Brian can see a phase jump.

Action items:
========
    (1) Calibrate chg0 with laser notching of the beam.
    (2) Check whether turning on RPOS/or phase feedback creates a
    phase jump and thus kicking the beam when it is turned on with the
    test system.
    (3) Chandra will talk about transition crossing in the next meeting.