1. Safe mode transmission
The issue as discussed in the meeting with the machine held on October 10
Proposal from people present at the meeting
Call for comments
First reactions
To be done
LEADE, 27/11/06
D. Macina TS/LEA

2. Movable devices and Machine Modes
Devices: Roman pots and LHCb Velo
If devices are at the end switch (OUT position): for all LHC modes UserPermit=TRUE
If devices move away from end switch AND MODE≠StableBeams AND MODE≠UnstableBeams then UserPermit=FALSE (results in a beam dump)
If LHC enters into MODE=StableBeams: devices can move away from end switch and UserPermit=TRUE
If LHC enters into MODE=UnstableBeams: devices can still be away from end switch and UserPermit=TRUE
Devices should move OUT
Devices should not be moved IN during such mode
(slides from R. Schmidt)

3. The mode is transmitted via the GMT system
Machine Modes
The mode is transmitted via the GMT system
The interface to the experiments is via a level (TTL or equivalent), coax or other cable
The interlock systems of the experiments requires the modes StableBeams and UnstableBeams
Options:
There is only one flag that is TRUE if MODE=StableBeams or MODE=UnstableBeams, else FALSE
There are two flags:
Flag 1 = TRUE if MODE=StableBeams, else FALSE
Flag 2 = TRUE if MODE=UnstableBeams, else FALSE
(slides from R. Schmidt)

4. Layout for Safe Machine Parameters distribution via the timing (idea from 7/8/2006)
Beam Energy Tracker
Energy 1
Beam Energy Tracker
CTG
Master Timing Generator
Energy 2
Events, UTC, & Telegrams
( including Safe Machine Parameters)
Timing Network
Operator / LSA
SBF1, SBF2
Energy
Mode
SqF
Mode
Squeeze
Currents
CSG
Safe Machine Parameter Generator
Injection kickers
BLM
Aperture Kickers
Experiments
Collimators
User_Permit
EI_th
Imin_th
E_physics
E_injection
deltaE, Emax
SqueezeMap
Critical Settings
LHC
BIS
CTRV
CTRV
CTRV
CTRV
CTRV
CTRV
BCT
I_beam1/2
BCT
SPS Extraction
BIS (TI8 / TI2)
CTRV
BPF1/2
(1 kHz)
(slides from R. Schmidt)

5. Meeting 10 october 2006 on Stable and Unstable Beam Flags (machine proposal)
Participants: B.Puccio, D.Macina, D.Swoboda, J.Serrano, R.Schmidt, J.Wenninger
Proposals: see slides
We propose the distributions of two flags:
Flag 1 = TRUE if MODE=StableBeams, else FALSE
Flag 2 = TRUE if MODE=UnstableBeams, else FALSE
There might be a very short time (order of nanoseconds) during the transition from StableBeams to UnstableBeams that both flags are FALSE
During this time, the User Permit should remain TRUE
Delivery of the flags to the electronics of the experiments will use cables connected to a GMT receiver in a VME crate
Using TTL, for limited distance
Using a unit that transforms TTL into RS422, for longer distances
Javier pointed out the development of the GMT system is in his section, and the installation and operation in Marc Vanden Eyndens section.
(slides from R. Schmidt)

6. Actions following the meeting
Machine proposal sent to all experiments on 13/10/2006
Only one comment from LHCb (R. Jacobsson) so far:
no glitch in between the Stable Beam and the Unstable Beam mode, not even picoseconds. A lot of work has gone into making this system immune to all sorts of effects (EMI, etc) and make it simple. Therefore, the logic which adds up the status flags with the user permit will not and should not have to include some mechanisms which exclude glitches.
LHCb proposal:
Safe Stable Beam flag is kept as is, that is only during the Stable Beams. Its absence will be used to signal the movable detectors to move out, automatically or on confirmation from operator.
A second flag "Movable Devices Allowed" (please, feel free to propose a different name) is added which is present during Stable Beams AND Unstable Beams without interrupt. It is this signal which would be ANDed together with the user permit to make up the beam permit sent to the CIBU.
signal is not produced in the GMT receiver but that it is produced in the Master Timing Generator together with the SB flags and that it is transmitted as a telegram to the Timing Receivers

7. Next actions
Identify in all experiments the people in charge of the interface to the BIC / GMT systems to be able to discuss technical details
ALICE (?)
ATLAS (Siegried Wenig, Nicolas Massol)
CMS (R. Hall-Wilton?)
LHCb (R. Jacobsson)
LHCf (?)
TOTEM (W. Snoyes)
Call for a meeting in order to take a decision on the technical implementation of the safe “stable & unstable” flag transmission