M Church 4/06/01

Dipole bus: Maximum ramp rate is 16 GeV/sec (as in operations). With main bus not ramping run C49 activate (file #1) and load DFG's from C50 (file #16), if not already done. Use C49 file #19 to change Tecar flattop energy to 900 GeV (see Instruct in Decelerate aggregate in Studies sequencer.) Turn Tevatron on to ramping state to 900 GeV (Recovery aggregate in Collider Sequencer). (L.B's will still be off, so make sure HE lead flows for L.B. quads are off.) Studies Sequencer has appropriate aggregates for training Tevatron up to 1010 GeV. Ramp dipole bus to 900, 950, 980, 1000, 1010. Stay at 900, 950,980,1000 for ~5 minutes each time; stay at 1010 for 2 hours. Watch lead voltages via T33. (Verify that T33 scaling is correct.) Also monitor lead temperatures (F14 <33>, <34>). Adjust lead flows in frig buildings if required. Make small adjustments to V and R limits from T33 only if necessary. (Save to Col1 file from T32.) Remember that only A4 has HTS leads and does not have adjustable lead flows. If quench occurs above 950 GeV, start over with a 950 GeV ramp.

Previous training quenches in warmed houses are at B13L(950 GeV), E26U(990 GeV), F48L(1005 GeV), F46U(1010 GeV), F42L(1010 GeV), B22L(1015 GeV), and B15L(1020 GeV). Magnet swapping and recoolers have been installed in some of these houses, so training performance may be different than in the past.

(Note: E4 was not retrained after the beamvalve replacement.)

Set to abort so that beam is kicked out after a few seconds of circulation. Look at C0 abort diagnostics (T69) to verify abort is clean. Test that diagnostics are working correctly by purposely mis-steering beam. Beam position should change, and losses should increase as beam is mis-steered. Attached is a drawing showing diagnostic setup at C0. Also use I41 to look at the two SWIC's in the beamline. Document T69 and I41 pictures in the Elog. M. Martens has determined that B49 is a vertical aperture restriction for beam on the proton helix. (See Tev Elog entry #51.) Measure abort efficiency and losses as a size of the B49 bump (currently at 3mm in the "desired orbit" file) in increments of 1/2 mm down to 0mm. With a bump of –2.7mm vertically (from the current orbit). measure the abort efficiency and losses as a function of C0 abort voltage (currently set at "6.6" on C49 and reads back between 6.0 and 6.5 KV on a parameter page). Repeat this last measurement with horizontal bumps of +-2mm at B49.

Addendum 3/23/01:

Check that beam on central orbit at 150 GeV aborts cleanly with the horizontal and vertical position bumps found on the 3/22/01 evening shift. Desired positions are HPB48=-2.7, HPB49=-3.3, VPB48=0, VPB49=0. Reinject beam and open proton helix and check that no beam loss is observed when helix is opened, and abort is efficient. (We expect it to be ok since the proton injection helix is x=.7, y=3.9 at the u.s. C0 Lambertson.) Repeat with beam on the the pbar helix to verify that there is no beam loss when helix is opened. Here, the abort may not be very clean, but hopefully it won't quench the Tevatron. If things look reasonable, edit the C50 "desired orbit" files and copy these bumps up the ramp.

Make another attempt to get T69 loss monitors to trigger correctly. T:LMABTR should be set to $47/$4B +0.0, T:LMABTH should be set to $47/$4B+.02 for T69 to display losses correctly. T:C0LMS should be $47/$4B +.005. Don't bother with the I41 SWIC's until RF&I and Controls group provides more documentation.

Addendum: (3/21/01)

Apparent local coupling at B0 should be investigated. To investigate apparent coupling, 1st set SQA4 and SQB1 to 0 and readjust tunes and coupling. In recent studies, the out-of-plane motion in the VPA49 3-bump was mostly corrected by a –5A change in SQA4 @ 150 GeV.

1) Document local coupling effect better: record out-of-plane oscillations for C50 5mm 3-bumps VPA47,VPA49, VPB11,VPB12, HPA46,HPA49,HPB11,HPB13 @ 150 GeV.

2) Corrector cabling has been checked in the tunnel. This needs to be checked in the service buildings: T:HA46, C:HA48, T:HA48, T:HA49, T:HB11, C:HB12, T:HB13, T:VA47, C:VA48, T:VA49, T:VB11, T:VB12, T:VB14. (JA, DS)

3) Local coupling is apparent with C50 bumps. Repeat at least one of these bumps from a parameter page mult to see if the result is consistent.

4) Is there a hysteresis effect? Ramp to 980 Gev and low beta twice and repeat the VPA49 3-bump.

5) The Q5's have very corroded stands. Make an inspection in the tunnel (bring a level). Request a formal survey if there appears to be significant roll.

6) Is there something in CDF that would have an effect? Repeat some of the measurements @ 980 GeV. For a rolled quad, we would expect the out-of-plane motion to be about the same.

7) Set abort to 1st turn and document the out-of-plane orbit oscillations from 1-bumps (horizontal and vertical) in F sector. This data can be used to calculate magnitude of a suspected roll, and narrow down the location.

Global: Do not start careful orbit corrections until BPM's have been fully verified.

B0/D0: Scan position and angle bumps to verify aperture is good

F0: See attached instructions, next page.

A0:

Do aperture scans with the A0 horizontal and vertical position and angle bumps at A0 (see T73 INJECT <14-15>. Do aperture scans with C50 3 bumps HF49, HA11, VF49, VA11. Do these at 150 GeV, central orbit, uncoalesced beam. Repeat some of the horizontal bumps with coalesced beam. See attached plots for some guidance.

M Church 3/16/01

1) Use 30 bunches, 2 turns; reduce injection oscillations to a "reasonable" level; store beam @ 150 GeV, LBSEQ=0.

3) Vertical: Center the circulating beam vertically in the Lambertson notch by doing an aperture scan with the vertical position bump. (You may have to first put in a horizontal position bump to move closer into the notch.) Align the circulating beam parallel to the notch by doing an aperture scan with the vertical angle bump. Then put a +3mm vertical position bump in.

4) Horizontal angle: For these adjustments, remove the +3mm vertical position bump from above. First get the angle correct. Very slowly move the beam into the notch with a horizontal position bump until losses just appear. Then very slowly change the horizontal angle bump, finding the direction which reduces losses. Increase this angle until losses are again seen. Split the difference between the initial angle and final angle. Scrape beam with the upstream E0 collimator (horizontally and vertically) and scan the horizontal angle bump to verify beam is parallel to the Lambertson. This may require some iteration to convince yourself you got it right.

5) Horizontal position: For these adjustments, also remove the +3mm vertical position bump from above. Scrape beam down to teeny-tiny, both horizontally and vertically, with the upstream E0 collimator. Then move the beam horizontally into the Lambertson notch with the horizontal position bump until losses appear. Keep going until beam just disappears, or Tevatron aborts. Then move the bump back (inward) by 4.5+10.0 = 14.5 mm. This should be a pretty good starting point if the beam was small transversally. Put the +3mm vertical bump back in. Reinject and close. This may require significant P1 line changes if the C.O. has changed significantly at F0. Now iterate on the following procedure to see if the horizontal position is optimized: Change the horizontal position at F0 by -1mm. Reinject and close. Abort on first turn and note F0 injection losses. Repeat in –1mm steps until injection losses become significant at F0. This marks the point where P1 beam is scraping the Lambertson. Now go in the other direction, letting the beam circulate and noting F0 losses from circulating beam. Find the point where the circulating beam is scraping the Lambertson. The correct horizontal position is halfway between the two beam loss points.

Addendum: 3/22/01

Helix has been opened to about 120% on pbar polarity before seeing beamloss and lifetime degradation. Helix has been opened to 90% on proton polarity before seeing beamloss and lifetime degradation. Aperture restriction has been located at B49 vertical. This may require an energy-dependent vertical bump at B49.

Addendum: 4/02/01

B49 orbit is optimized for clean abort. No energy dependent bump is required.

Previous A0 kicker timing studies can be found in old Tev logbook entry #260. At the end of the engineering run T:CPATRG was set to .377 Trev.

Fix communication with A0 proton kicker scope (Still, Briegel)

Measure kicker risetime at 150 GeV setting (9.44KV) and 980 GeV setting (38.KV) and note difference.

Accelerate to 980 GeV and test. Change delay by ±7 RF buckets (or more) to find optimum.

Retest at 150 GeV and 980 GeV on the proton helix.

These studies will need to be repeated if we modify the desired orbit at A0.

Use Timeline module 128 (MIà Tevà MI), Use a $2B/$4D module followed by a $2A/$5D about 40 seconds later, and Collider sequencer aggregate "reverse injection tuneup". This aggregate is set up to open and close helix, in pbar polarity, automatically on injection and extraction events. Extraction will be done on the pbar helix. First, test mechanics of the aggregate. Second, test A150 PS's and load switches. Extraction bumps should be local. Extraction bumps should be adjusted so that vertical positions at F0u and F0d are the same as on the injection bumps. (Injection bump displays are taken at $4D+2.71 sec; extraction bump displays are taken at $5D +6.69 sec.) Assuming the F17 kicker has a kick of .320 mrad, this gives a beam separation at the Lambertson of 20.5mm (and about .01 mrad angle). Assuming the E48 kicker has a kick of .390 mrad, this gives a beam separation of 29.0 mm at the Lambertson and an angle of .48 mrad. (The Lambertson's are 15m long.) Assuming that the A150 line has been laid out to account for this angle, start by setting the horizontal extraction bump to put the circulating beam –2 mm wrt the injection bump at F0u and F0d. Bump should be local. This position will need to be scanned (along with horizontal extraction angle, possibly) in order to optimize the extraction orbit and minimize losses.

Kicker times should be; T:KE48D1=54.76Mrev; I:K6AKD1=54.03911Mrev, I:K6BKD1=54.09864Mrev.

Extraction beam synch is $D8_MIBS which occurs at $5D+6.7 sec. Reflected TCLK event is $55. $D8_MIBS enabling event is I:TMIPX.

Start with 2 turns 30 bunches, uncoalesced beam. Tune up MIà Tev transfer to 100%+. Check to see if any beam is left over in the MI by delaying the abort timer (I:ACUP2B) to as late as possible before MI rampdown ($2B+2.75) and seeing if any beam is left in MI after transfer to Tevatron. Save FTP's and SNP's of Tev DCCT, MI DCCT, TOR702, and TOR714 on a scale that will allow calibration to a few %. Change timers on toroids (I:T714T3) +- to see if we are near the edge of good S/H time. Check Tev DCCT calibration locally (RF&I) to determine which of MI or Tev DCCT calibration needs changing, if any. Recheck calibration with 4 turns, 30 bunches.

Check calibration with 4 turns, 5 bunches, uncoalesced. In this case, the central bunch should be at the MI $AA marker on TV channel MI #16, and should land in Tev bucket #1. Now check Tevatron FBI calibration. (C:FBISUB should be 1, C:FBIPWW should be 9, C:FBISQL should be 2E9 to start.) Measure FBIBWG and FBIPWG[1] as a function of FBIPWW. Does it behave as expected, and does it converge to FBIPNG when FBIPWWà 1? When FBIPWW is ≥5, FBIPWG should equal T:IBEAM. How do the sum signals vary with FBISQL?

Cog pbars wrt to protons so that the protons are in the pbar gates. Use this signal to calibrate the pbar FBI's.

Set up for reverse protons (see above). Close in MI with uncoalesced beam and then try reverse injection with with low intensity uncoalesced beam, noting transfer efficiency and F0 losses.

If efficiency wasn't so bad for low intensity, repeat the measurements for higher higher intensity: 5 turns, 7 bunches.