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Configurations for Special Runs / VdM in 2022

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Contents

 

VDM scan 2022

Low-µ run for LHCf

90m run

 

 

 

 

AGK after TS1

It remains to be determined if a different AGK setting will be needed for the vdM and LHCf run (likely not).

VdM programme 2022

The following is largely based on 2018 procedures and expected to evolve in future discussions.

The VdM programme is scheduled to start after the 3b validation fill and vdM cycle validation after TS1 and will be interleaved with the LHCf low-µ run. This will probably fall on the weekend of the 17/9/2022 with . The programme consists of the following steps (no turn-around times taken into account here).

Maximum separation allowed by MPP: 2.5 nominal σ for each beam in one plane at a time. Separation in both planes at the same time are not allowed. The limits are given in terms of nominal emittance : εn=3.5µm. This means that the de-facto separation is larger since we in fact run with lower emittance (~2.3µm - to be updated). 

Step Duration Experiments activities Remarks
3b validation fill - low ß* optics 30min  
ATLAS CMS MPP
head-on head-on
4min : emittance scan
Go to Stable beams; RP insertion? (AFP or ALFA in IP1? PPS?); No ß* leveling

 

30min Stable Beams for MPP
Need 3b fill with vdM optics as well for MPP?

 

Non-linearity measurement fill (3b - vdM optics) 2h  
ATLAS CMS
1h   : scan of beam 1 No movement ("head-on")
1h   : scan of beam 2

 
Filling Scheme:
  1-3 non-colliding nominals in each beam. No long-range anywhere
Could potentially be done during final vdM cycle validation
TBD if CMS would like to do the same type of scan
Calibration transfer fill (140b - low ß* optics) 4.5h  
ATLAS CMS MPP
2h   : immediate beam separation to µ=0.5 after optimisation head-on CMS 1h head-on
RP insertion
0.5h: maximal beam separation
1h   : µ-scan
1h   : head-on 45min : µ-scan ATLAS 1h head-on

 
Filling Scheme:
Multi_525ns_140b_140_75_16_8bpi_19inj.csv
Scheme optimised for few AGK changes (might change for 2022)
No ß* levelling (stay at 60cm)
LHCf run (vdM optics) 2-4 days
 
  See details below
 
Filling Scheme:
Multi_525ns_152_150_0_0_8bpi_19inj.csv
LHCf removal 8 hours
 
  Access to tunnel to extract LHCf detectors
 
Scans IP2/8

8h45min
(plus overhead)

 
LHCb ATLAS ALICE
1h : LHCb part 1    
  2h : ATLAS Length scale calibration  
2h15min : LHCb part 2     
    3h30min : ALICE scan

 

Filling Scheme:
Multi_70b_58_20_22_4bpi_19inj.csv

Scans IP1/5

15h45min
(plus overhead)

 
ATLAS CMS
1h : ATLAS part 1  
  3h30min : CMS part 1
3h : ATLAS part 2 (non-factorization)  
  1h30min : CMS part 2
2h : ATLAS part 3  
  3h30min : CMS part 3
1h ATLAS part 4  
  15min : CMS emittance scan & super separation
(6 sigma total in x/y)

 

Filling Scheme:
525ns_140b_124_32_23_16bpi_11inj.csv

ATLAS 1 2 and 3 4 need to be in same fill

CMS: 1 and 2 need to be in same fill
if beam is lost in cms part three, we need to refill

600b - ramp up fill 5h
 
 
ATLAS CMS MPP
head on emittance scan 1h head-on each IP
RP insertion
ß* leveling to all ß* settings
> 2h total

 
Filling Scheme:
25ns_603b_590_524_542_48bpi_17inj
More special runs here?
Normal physics fill optimal  
 
Filling Scheme:
Default 2022 full ring - TBA
To be seen if additional intermediate fill needed as part of ramp-up

Beam parameters for Calibration Transfer fill

Items Remarks
Filling Scheme Multi_525ns_140b_140_75_16_8bpi_19inj.csv
Bunch Spacing 525 ns (minimal)
Injections up to 2 batches of 4 bunches
Emittance in Stable Beams tolerable variations: 2µm to 3µm
Intensity in Stable Beams 1.2x1011 ppb  --  tolerable variations: 1.1x1011 ppb to 1.25x1011 ppb; 
Brightness (bunch intensity / emittance) < 0.5 x 1011 ppb / µm

 

Beam parameters for Scans in IP2 and IP8

Items Remarks
Filling Scheme Multi_70b_58_20_22_4bpi_19inj.csv
Bunch Spacing 1000 ns (minimal)
Injections up to 4 batches of 1 bunch ("traditional" VdM schemes)
Emittance in Stable Beams 3µm for LHCb;  >3µm for ALICE (second in scan programme)
Intensity in Stable Beams 0.7x1011  - 0.9x1011 ppb in LHCb
0.4x1011  - 0.9x1011 ppb in ALICE (Alice is second in the scan programme)
Profiles Preparation for VdM : Gaussian profiles which factorise the beam wrt H and V planes
IP 8 Dipole polarity + / +
IP 8 external half crossing angle  145 µrad; internal half crossing angle : -75 µrad --> effective half crossing angle at IP: 70 µrad which is ok for using the ZDC.
Injection Optics With crossing angle to not have problems with LR interactions when beams are large at injection
IP2 polarities + / + (Dipole and L3 magnet)
IP2 internal crossing angle -75µrad
IP2 external crossing angle 145 µrad
IP2 effective crossing angle +70µrad
IP2 y - vertex shift -1 mm

 

Beam parameters for scans in IP1 and IP5

Items Remarks
Filling Scheme 525ns_140b_124_32_23_16bpi_11inj.csv
Bunch Spacing 525 ns (minimal)
Injections up to 4 batches of 4 bunches
Emittance in Stable Beams 3µm -- tolerable variations: 2µm to 4µm; some spread O(20%-30%) is welcome
Intensity in Stable Beams 0.85x1011 ppb  --  tolerable variations: 0.70x1011 ppb to 0.95x1011 ppb;  some spread O(20%-30%) is welcome
Profiles Preparation for VdM : Gaussian profiles which factorise the beam wrt H and V planes
IP 8 Dipole polarity + / +
IP 8 external half crossing angle  145 µrad; internal half crossing angle : -75 µrad --> effective half crossing angle at IP: 70 µrad which is ok for using the ZDC.
Injection Optics With crossing angle to not have problems with LR interactions when beams are large at injection
BGV measurements Requested by CMS (to be followed up by LPC)

 

Low-µ run for LHCf

The LHCf run is scheduled to start shortly after the first luminosity calibration related fills after TS1 This will probably start around of the 20/9/2022 with up to four days of data taking foreseen.

LHCf will take data with their detector in two different positions. AFP or ALFA roman pots to be inserted as well. The luminosity request is for about 40/nb per detector position. This will take about 26 hours of stable beam per position with 150 colliding bunches.

Beam parameters for LHCf run

Items Remarks
Filling Scheme Multi_525ns_152_150_0_0_8bpi_19inj.csv
Bunch Spacing 525 ns (LHCf could go to 200ns, but would require a different filling schemes)
Injections up to 4 batches of 4 bunches
Emittance in Stable Beams 3µm
Intensity in Stable Beams 0.85x1011 ppb
Beam crossing in IP1 Vertical, downward
Luminosity leveling in IP1 Offset leveled to µ=0.02
Beam crossing in IP5 CMS requested to run with zero crossing - might do some luminosity-related scans

 

90m run for TOTEM

The 90m run is scheduled for taking place after TS2 when the new T2 detector is installed, nominally around 10/11/2022.

The squeeze for this fill will be very long (40m - TBC) and might go to 120m to achieve the optimal pile-up level.

The TOTEM roman pots will be inserted close to the beam, so there will be no stable beam and beam should stay below "SETUP BEAM" limits (3x1011 protons.

Beam parameters for TOTEM run

Items Remarks
Filling Scheme 4 colliding bunches in IP1/5, all well separated
Emittance in Stable Beams Ideally 3µm as otherwise need lower intensity or larger ß*
Intensity in Stable Beams 0.6-0.7x1011 ppb
Target pile-up level in IP6 µ=0.04-0.1
No offset leveling allowed
Beam crossing in IP5 Zero crossing
Target luminosity About 1/nb - should take around 6 hours

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