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Configurations for Special Runs / VdM in 2022

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The data shown here is "work-in-progress"

 

The parameters on this page reflect the best current knowledge and will be regularly updated and changed accordingly. Please consider this when using these parameters for any estimate. In case of doubts do not hesitate to ask the LPC.

 

The special run program has been split in two, with the non-linearity scan, LHCf run at 19m and a calibration transfer done right TS1, while the regular vdM scans will be done after MD2

Contents

 

Low-µ run for LHCf

2022 VDM scan

 

AGK after TS1

AGK remains unchanged at bucket 31751.

Separation requirements for scans

Maximum separation to be requested in MPP: 3 nominal σ for each beam in both planes at the same time for the vdM cycle.. This might require a set dedicated loss map - TBC after discussion with MPP. For low-β optics 3 nominal σ for each beam in one plane at a time is sufficient (this might not actually be enough for the calibration transfer fill). 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 (~1.8µm - to be confirmed for Gaussian shaped beams). 

Special run programme post TS1

Step Duration Experiments activities Remarks
Machine recovery and setup of 19m cycle for LHCf run/vdM scans 2 days None  
Non-linearity measurement fill (3b - 19m optics) 2h  
ATLAS CMS
1h   : scan of beam 1 No movement ("head-on")
1h   : scan of beam 2

 
Filling Scheme:
Single_3b_0_2_2.csv
Stable Beam not required, but it needs zero-crossing angle.
It can also be scheduled after the LHCf fills.
LHCf run (19m optics) 3-4 days
 
  See details below
 

Filling Schemes:
50b ramp-up: 525ns_50b_48_8_13_8bpi_8inj_800ns_bs525ns.csv
146b main scheme: 525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv

End-of-fill test in one fill for ATLAS for crossing angle sensitivity, reducing crossing angle to zero (1 hour)
Not possible due to extra validation overhead

LHCf removal 8 hours
 
  Access to tunnel to extract LHCf detectors
 
Has to be done during working hours.
Revalidation of low beta* optics 2-3 days None  
Calibration transfer fill (140b - low ß* optics) 7h  
ATLAS CMS
2h   : immediate beam separation to µ=0.5 after optimisation. AFP insertion head-on
0.5h: maximal beam separation
1h   : µ-scan
5min: maximal beam separation
15min: ß* levelling to 30 cm for maximum pile-up
1h   : µ-scan
2h   : head-on 45min : µ-scan (TBC)

 
Filling Scheme:
Multi_525ns_140b_140_75_16_8bpi_19inj.csv
ß* levelling to 30 cm only after first µ scan
150b - Ramp-up fill with trains 2h
 
 
MPP
2h head on in IP1/5
RP insertion
ß* leveling to all ß* settings

 
Filling Scheme with 1x36b:
25ns_159b_146_128_134_36bpi_8inj_3INDIV.csv
600b - ramp up fill 2h
 
 
CMS MPP
emittance scan 2h head-on in IP1 and IP5
1h with VELO inserted
RP insertion
ß* leveling to all ß* settings
> 2h total

 
Filling Scheme:
25ns_591b_578_510_540_72bpi_12inj_3INDIV.csv
1200b - ramp-up fill 5h
 
 
CMS MPP
emittance scan 2-5h head-on each IP
RP insertion
ß* leveling to all ß* settings
> 5h total

 
Filling Scheme:
25ns_1167b_1154_1022_1088_144bpi_12inj_3INDIV.csv
Normal physics fill optimal Back to normal physics data taking  ATLAS toroid ramped up before in interfill
 
Filling Scheme:
5x36b train with INDIV for LHCb: 25ns_2461b_2448_1737_1733_180bpi_16inj_1INDIV.csv

Special run programme post MD2

Step Duration Experiments activities Remarks
3b validation fill - 19m optics 30min  
ATLAS CMS MPP
head-on head-on
4min : emittance scan
Go to Stable beams?

 

30min Stable Beams for MPP

 

Validate changing crossing angle in IP1 from 0 to 160urad

Scans IP2/8

10h45min
(plus overhead)

 
LHCb ATLAS ALICE
1h : LHCb part 1    
  4h : ATLAS Length scale calibration  
2h15min : LHCb part 2     
    3h30min : ALICE scan

 

Filling Scheme:
Multi_70b_58_20_22_4bpi_19inj.csv

Scans IP1/5

18h
(plus overhead)

 
ATLAS CMS
7h : ATLAS  
  7h : CMS
2h : ATLAS experimental 2D scan  
  2?h : CMS diagonal scan
  15min : CMS emittance scan & super separation
(6 sigma total in x/y)

 

Filling Scheme:
525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv

The ATLAS and CMS scans will likely be interleaved

1900b - mu variation fill 12h
 
 
ATLAS CMS
1h: µ-scan
Long decay of µ (remaining part of fill) emittance scan

 
Filling Scheme:
/25ns_1935b_1922_1758_1842_240bpi_12inj_800ns_bs200ns_3INDIVs
To be changed according to trains used at the time.
High luminosity fill with 3 INDIV bunches. No ß* leveling.
Normal physics fill optimal Back to normal physics data taking 
 
Filling Scheme:
Default 2022 full ring 25ns_2748b_2740_2250_2376_240bpi_13inj_800ns_bs200ns
To be changed according to trains used at the time.

van-der Meer scan in 2022

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 Down, +
IP 8 external half crossing angle  -300 µrad; internal half crossing angle : -140 µrad --> effective half crossing angle at IP: -440 µrad.
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 -72µrad
IP2 external crossing angle 145 µrad
IP2 effective crossing angle +73µrad which is ok for using the ZDC
IP2 y - vertex shift -1 mm

 

Beam parameters for scans in IP1 and IP5

Items Remarks
Filling Scheme 525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv
Bunch Spacing 525 ns (minimal)
Injections up to 2 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 2 Dipole polarity +
IP 2 external half crossing angle  145 µrad; internal half crossing angle : -72 µrad --> effective half crossing angle at IP: 73 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 after the setup of the 19m vdM/LHCf cycle after TS1. This will probably start around of the 22/9/2022 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 28 hours of stable beam per position with 140 colliding bunches.

Beam parameters for LHCf run

Items Remarks
Filling Scheme 525ns_146b_144_35_22_8bpi_20inj_nocloseLR.csv
Bunch Spacing 525 ns (LHCf could go to 200ns, but would require a different filling schemes)
Injections up to 2 batches of 4 bunches
Emittance in Stable Beams 2µm
Intensity in Stable Beams 1.1x1011 ppb
Beam crossing in IP1 Vertical, downward 290µrad total
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

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