Dedicated MD 2025-07-09

Objectives

Flatten momentum ramp on SFTPRO & correct feed-forward eddy current.

Preparation

Measure SFTPRO1 at first turn with at least 0, 1, 2, 3 ZERO steps [completion:: 2025-07-10]
Prepare notebooks for retrieving first turn data [completion:: 2025-07-10]
Mask out BPMs and BPCE in YASP [completion:: 2025-07-10]
Remember to move PS cycles along PS BCD when adding ZEROs [completion:: 2025-07-10]
Add flattening feature in GUI [completion:: 2025-07-10]

As backup, we look at LHC-type cycle

MD

Eddy current data taking.

Normal MD1

SFTPRO1 - MD1 - SFTPRO1 - MD1 - SFTPRO1 - MD1 + ZEROS

query_ssc0 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:05:00.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:11:00.000+02:00"),
)
 
query_ssc1 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:14:50.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:20:45.000+02:00"),
)
 
query_ssc2 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:20:45.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:26:00.000+02:00"),
)
 
query_ssc3 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:26:00.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:31:30.000+02:00"),
)
 
query_ssc4 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:31:30.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:36:00.000+02:00"),
)
 
query_ssc5 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:36:20.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:41:22.000+02:00"),
)
 
query_ssc6 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 12:41:22.000+02:00"),
    dateutil.parser.parse("2025-07-09 12:46:00.000+02:00"),
)
 
query_ssc7 = nxcals.query_for_time(
    dateutil.parser.parse("2025-07-09 15:05:00.000+02:00"),
    dateutil.parser.parse("2025-07-09 15:20:00.000+02:00"),
)

Flattened MD1

SFTPRO1 - MD1 - SFTPRO1 - MD1 - SFTPRO1 - MD4 (flat MD1) + ZEROS

query_ssc0 = nxcals.query_for_time(
    "2025-07-09 14:12:30.000",
    "2025-07-09 14:21:20.000",
)
 
query_ssc1 = nxcals.query_for_time(
    "2025-07-09 14:04:30.000",
    "2025-07-09 14:12:10.000",
)
 
query_ssc2 = nxcals.query_for_time(
    "2025-07-09 13:56:10.000",
    "2025-07-09 14:04:00.000",
)
 
query_ssc3 = nxcals.query_for_time(
    "2025-07-09 13:47:30.000",
    "2025-07-09 13:54:40.000",
)
 
query_ssc4 = nxcals.query_for_time(
    "2025-07-09 13:34:40.000",
    "2025-07-09 13:45:10.000",
)
 
query_ssc5 = nxcals.query_for_time(
    "2025-07-09 13:25:30.000",
    "2025-07-09 13:34:40.000",
)
 
query_ssc6 = nxcals.query_for_time(
    "2025-07-09 13:14:40.000",
    "2025-07-09 13:25:10.000",
)

Flatten SFT at 16:09

Flatten SFT IREF (not momentum and RF) https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338131

Flatten SFT momentum https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338138

8e-5 T moves first turn by 3.1 mm (4.6 mm to 1.5 mm) https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338138

Field difference caused by trim https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338146

Fix dB trim runaway when using eddy current correction only [priority:: high] [due:: 2025-07-11] [completion:: 2025-08-01]

Increase previous exponential decay by 0.45e-4 T to move the first turn from 1.5 mm to ideal orbit, but we lose the beam anyways https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338176

Shift injection field by 1.3e-4 T to not do a decaying field, we lose beam anyways after a few turns https://logbook.cern.ch/elogbook-server/GET/showEventInLogbook/4338178

16:49:38 change back to constant 1.3e-4 T offset 16:51:10 revert

Action

Investigate effects on $b_{3}$ (sextupole component) caused by eddy current decay. Do sextupole decays with the same time constants as the dipoles? https://cds.cern.ch/record/1014025/files/ab-note-2007-009.pdf

Next experiment

BBQ saves data to /user/slops/data/SPS_DATA/OP_DATA/QMETER

17:42:00 Start

SFTx2 + ZERO

The first SFTPRO we look at injection

Move BHYS by +0.6e-4 to move orbit from 2.2 mm to move orbit at 17:45:27 The first turn on the first SFT is set to 0, the second one shifts by -2mm. We see the tune changes on the first one to be almost nominal. ??Why? 17:49:43 change trim back to 0.

We manage to move te first turn by 0.8 G, leaving 0.45 G to idea orbit.

Hysteresis Compensation

Explorer