Distribution of machine parameters over GMT in the PS, SPS and future machines J. Serrano, AB-CO-HT TC 6 December 2006

GPS One pulse per Second GPS Smart clock PLL One pulse per Second Phase locked 10MHz Basic Period 1200/900/600 ms Advanced (100us) One pulse per Second Synchronized 1KHz (slow timing clock) Phase locked 10MHz Phase looked 40 MHz Event encoding clock 40MHz PLL CTSYNC RS485 Timing CTGU The new generation low jitter <1ns VME based MTG module UTC time (NTP) Event tables External events General Machine Timing (GMT) Hardware Architecture CERN UTC Time Set once on startup & on Leap Seconds RS485 Timing CTRP 40 MHz 10 MHz 1 KHz 1PPS Delay Control System CERN UTC Time 25ns steps Timing receiver

Four reasons: 1) Initial SLP project would lead to a 3rd “Timing Network”. 2) Failure Scenarios (Ruediger’s paper) have demonstrated that SIL3 is not required. 3) Bandwidth requirements on LHC- CTG are not very stringent. 4) Timing team was interested in improving the overall safety level of GMT. Why Safe Beam Parameters distributed via the Timing system? => Decision taken by MI & HT and approved by MPWG in the end of 2005: The Safe Beam Parameters will be transmitted and received using Timing solutions. A cross check will be performed by a dedicated system. The latter could possibly dump the beam in case of error.

Beam Parameters  Non-safe (i.e. not hardware-checked):  Mostly contained in the telegram, broadcast every basic period. Example: the PS telegram contains Particle Type, Harmonic Number, Primary Destination for the beam, etc.  In the LHC, the mode will be broadcast using this mechanism, or something similar.  Safe (i.e. hardware checked):  Strategy: make an unsafe system become safe through addition of external hardware checks.  In the LHC, these parameters include (so far) Beam Energy, Beam Intensity, Safe Beam Flag and Beam Presence Flag, Stable Beam Flags.  Upcoming meeting (18 Dec.) on distribution of stable and unstable beam flags for experiments.  Concept proven in the SPS this year, through the Safe Beam Flag.

B.P. & R.S EI_th, Imin_th E_physics, E_injection deltaE, Emax, CSG Safe Machine Parameter Generator Energy 1 I_beam1 & 2 CTRV SBF1, SBF2 Energy Mode SqF Mode & Energy 2 SBF1 & 2 Layout for Safe Machine Parameters distribution via the timing (idea from 7/8/2006) + Revision 17/11/2006 BEM SPS Extraction BIS (TI8 / TI2) BCT BEM Operator / LSA Management Critical Settings Squeeze Currents BPF1 & 2 (1 kHz) Timing Network Events, UTC, & Telegrams ( including Safe Machine Parameters) CTRV LHC BIS Beam_Permit1 & 2 (CTRV) CTRV Injection kickers BLM Aperture Kickers Experiments Collimators LBDS Beam Dump syst. User_Permits CTG Master Timing Generator CTRV BEM interface PM Even t Suppression PM Event Trigger

User Access to GMT- Distributed Beam Parameters  Users can access Beam Parameters in hardware (front panel of CTR cards) or software (reading the memory of any CTR).  Timing receiver cards are available in three formats: PCI (CTRI), PMC (CTRP) and VME (CTRV).  The CTRV also contains special P2 connector signals to suit BLM and kicker needs.  Flags available in the front panel use the retriggerable variable width feature of CTR outputs, for fail-safe operation.

Future plans  Q1 2007: validate LHC MTG concept and install a first version of it in the CCR.  Q2 2007:  Initiate transmission of dummy LHC beam parameters.  Integrate real data providers as they become available: first Beam Energy, then Beam Intensity.  Q3 2007: integrate solution to protect front end settings in timing receiver cards.  Q3 2007: add full hardware check (MI section) to the system to close the loop.