1. Update on ALICE-LHC interfaces & BCM
Technical Forum, 25/03/10
Antonello Di Mauro
Status of data exchange
Cogging with BPTX and BPIM FW upgrade
BCM response and thresholds studies
Outlook

2. Status of data exchange
List of parameters to be published via DIP to LHC fully reviewed (EDMS LHC-OP-ES-0018), some data are also displayed in the LHC_Config and LHC_Operation Vistar pages
DIP directory name
Description
Source
dip/ALICE/LHC/ExptStatus
State of experiment (STANDBY, PHYSICS, ...)
DCS
dip/ALICE/LHC/BKGD
Background monitoring
BCM, SPD, V0
dip/ALICE/LHC/IntensitiesPerBunch
Arrays of bunch intensities
BPTX/BPIM
dip/ALICE/LHC/Luminosity
Total instantaneous lumi. [cm-2s-1] + coll. rate
V0-AND
dip/ALICE/LHC/LumiPerBunch
Instantaneous b-by-b lumi. [cm-2s-1]
dip/ALICE/LHC/LumiScan
Coll. rate, errors, integration time
SPD, V0-AND, ZDC
dip/ALICE/LHC/FillLumi
Total delivered and recorded lumi / Fill [cm-2]
dip/ALICE/LHC/LuminousRegion
H, V and centroid, tilt angles
HLT, SPD
dip/ALICE/LHC/AbortGap
No. of protons in the abort gap in each beam
dip/ALICE/LHC/Handshake
Injection, Adjust and Beam-Dump HS states
dip/ALICE/LHC/Timing/BPTX1 or 2
Phase, wrongBucket-flag and wrongBucket-array
dip/ALICE/LHC/Timing/BPTX
DeltaT of colliding bunches (shift from IP=0)
25/03/10
ALICE-LHC Interfaces

3. Status of data exchange
All selected data from LHC subsystems and instrumentation published over DIP (machine configuration parameters and status, BLM, BPM, BCT, collimators, vacuum gauges) retrieved, treated and transferred by DCS to OCDB
Treatment (smoothing) of data necessary to reduce memory load but also to fulfill other requirements (correlations between ALICE and LHC data,…)
New project for online data analysis tool (G. De Cataldo)
25/03/10
ALICE-LHC Interfaces

4. Status of data exchange
PVSS
Distrib. Sys.
OFFLINE
HLT
LOCAL
archive
OCDB
FXS
DIM
LHC-ALI_DCS
LHC
ECS
DIP
DIM
BPTX V0 T0
ZDC
SPD
PIT
BCM PM
…….
PVSS
Distrib. Sys.
V0_DCS
V0_DCS
DIM
V0_DCS
ACR-DISPLAY
CTP
From G. De Cataldo
25/03/10
ALICE-LHC Interfaces

5. Cogging with BPTX and BPIM FW upgrade
Using scope and BPIM boards (from LHCb) to readout BPTX signal
BPIM FW developed by E. Scapparone, only for triggering in 2009, phase measurements (BPTX1-BC1, BPTX2-BC1, …) done with scope
BPTX arrival time difference used to calculate collision coordinate, LHC RF adjusted to set Z~0
BPTX-1 – IP2 = mm
BPTX-2 – IP2 = mm
(DTOF = ns)
BPTX-1 cable delay = ns
BPTX-2 cable delay = ns
Estimated offset
DT(B1-B2)= ± ns
BPTX-C
(on beam-2)
BPTX-A
(on beam-1)
25/03/10
ALICE-LHC Interfaces

6. Cogging with BPTX and BPIM FW upgrade
23 Nov 2009
Beam-1 bucket 1
Beam-2 bucket 8911
Without cable+ beam TOF
estimated delay correction ns
-> Measured Vertex Z = -1.3 cm
25/03/10
ALICE-LHC Interfaces

7. Cogging with BPTX and BPIM FW upgrade
ATLAS
CMS
Measured vertex Z used to x-check/calibrate DT offset, corrected value: ns
25/03/10
ALICE-LHC Interfaces

8. Cogging with BPTX and BPIM FW upgrade
New FW (from LHCb, adapted by E.Scapparone) installed in BPIM readout boards, producing:
bunch-by-bunch intensity
filling scheme check (ghost bunches, wrong bucket)
abort gap
phase shift (B1-BC1, B2-BC2)
DT(B1-B2) (z coordinate of IP)
Commissioning in progress (in collaboration with LHCb), triggering working as usual, publication of bunch-by-bunch to be optimized
25/03/10
ALICE-LHC Interfaces

9. BCM response and thresholds studies
MKI injection failures can produce TDI grazing resulting in large splashes reaching ALICE
TDI grazing events produced by TDI setting up (jaws scan) or MKI delay scan have been used to check BCM response and estimate fluxes in ALICE
68,6 m
78,1 m
25/03/10
ALICE-LHC Interfaces

10. BCM response and thresholds studies
BCM-A
8 sensors
z = + 6 m, r = 10 cm
BLM-MWBMD
BCM C
7 sensors
z = m, r=10 cm

11. BCM response and thresholds studies
Beam dump logic:
Fast abort on RS1 (integration over 40 ms) or RS2 (integration over 80 ms) coincidences:
dump the beam if 3 adjacent diamond sensors out of 4 show a current > thrRS1 or thrRS2 , respectively
Slow abort on RS32-Sum (1.28 ms):
Sorting out the two highest and the lowest of 8 sensors, dump the beam if RS32-Sum > thrRS32
Doses from misinjected beam were presented in ALI-INT , updated by B. Pastircak in 2008 providing fluences in subdetectors. For BCM-A grazing on pilot bunch, fluence ~ /cm2
25/03/10
ALICE-LHC Interfaces

12. BCM response and thresholds studies
MKI
delay
scan
BCM threshold 4000 nA
Beam dump
in 3 turns
200 nA
25/03/10
ALICE-LHC Interfaces

13. BCM response and thresholds studies
BCM response: 100 part/cm2 ~ RS2: 1 nA
Fluence from FLUKA simulation: 2 x 10-5 /p
1 pilot bunch (5x109 p)-> 105 part/cm2 ~ 1000 nA, as observed during the MKI delay scan, consistent with BLM response RS1 ~ 0.5 Gy/s (using conversion factors: 5.4x10-6 C/Gy , 2x10-15 C/part, 60 cm2 area)
4x72 bunches of 2x1011 -> 109 part/cm2 ~ 10 mA
Proposed thresholds:
RS1: 1500 nA, RS2: 750 nA -> ~ 5-7 x 105 part/cm2
RS32: 200 nA -> background ~ 500 part/cm2
25/03/10
ALICE-LHC Interfaces 13

14. Outlook
BCM system instability on Post-Mortem events thoroughly checked, fixed with patches in PVSS and new simple procedure for shifter; further improvements to be discussed
Implementation of BLM dedicated panel for shifter
HW emergency buttons (ALICE-> SAFE, Beam-Abort)
Implementation of Safe-Machine Flags from GMT (HW signals, not via DIP) to control transitions SAFE <-> NOT-SAFE
Background monitoring (online and offline) dedicated effort
25/03/10
ALICE-LHC Interfaces