Names are broken down into the standard parts, DeviceType : Area : Position : Attribute
| Name | Description |
|---|---|
| ACCL | Used for everything in the RF system that is part of the general physics and operations interface at the cavity level |
| GUN | Used for everything in the gun |
See https://slacspace.slac.stanford.edu/sites/lcls/lcls-2/wd/dsg/Forms/AllItems.aspx, Naming Convention section 6.1.2.2
| Area | Physical Location |
|---|---|
| GUNB | LCLS-II Gun |
| L0B | LCLS-II L0 Accelerator Region |
| L1B | LCLS-II L1 Accelerator Region |
| BC1B | LCLS-II Bunch Compressor 1 |
| L2B | LCLS-II L2 Accelerator Region |
| BC2B | LCLS-II Bunch Compressor 2 |
| L3B | LCLS-II L3 Accelerator Region |
| SYS2 | Full LCLS-II Accelerator scope, e.g. global phase offset |
See https://slacspace.slac.stanford.edu/sites/lcls/lcls-2/wd/dsg/Forms/AllItems.aspx, Naming Convention section 6.1.2.3.2
The position of the gun is 100. The position of the buncher is 455.
The position of a superconducting cavity is 4 numbers where the first two indicate the cryomodule and the second two the cavity. For example, 0430 is cryomodule 4, cavity 3.
Cryo Module # | Description |
01-35 | CM01-CM35, 1.3GHz cavity |
H1 | 3.9GHz Cryomodule 1, located in L1B and follows CM03 |
H2 | 3.9GHz Cryomodule 2, located in L1B and follows H1 |
Numbering of cavities within a cryomodule:
| R/W | Name | Description | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| R | GACT | Measured gradient from cavity probe (MV/m) | |||||||||||||||
| R | GMAX | Maximum allowable gradient (MV/m) - readback only | |||||||||||||||
| R/W | ADES | Operation amplitude setpoint (MV) | |||||||||||||||
| R | AACT | Measured amplitude from cavity probe (MV) | |||||||||||||||
| R/W | AMAX | Maximum allowable amplitude (MV) | |||||||||||||||
| R/W | PDES | Operation phase setpoint (degrees, where 0 is on-crest) | |||||||||||||||
| R | PACT | Measured phase from cavity probe (degrees) | |||||||||||||||
| R/W | SEL_POFF | SEL phase offset setpoint (not used in SELA mode) | |||||||||||||||
| R/W | PREF | a.k.a.gold, phase offset used by LLRF to convert measured phase to one relative to on-crest operation, adjusted by beam phasing (degrees) | |||||||||||||||
| ? | DFDES | Cavity detuning setpoint (Hz) - is this needed? | |||||||||||||||
| R | DFACT | Detune seen by the resonance system (Hz) | |||||||||||||||
| R/W | RFMODECTRL | RF mode control (SEL, SELA, SELAP) | |||||||||||||||
| R | RFMODE | Readback of current RF mode | |||||||||||||||
| R/W | RFCTRL | Cavity on/off control. Off = LLRF drive set to 0. (SSA control will be different.) | |||||||||||||||
| R | RFSTATE | Readback of cavity RF on/off state | |||||||||||||||
| R | AWF | Waveform of cavity probe amplitude, which is used to calculate AACT (MV) | |||||||||||||||
| R | PWF | Waveform of cavity probe phase, which is used to calculate PACT (degrees) | |||||||||||||||
| R | FWD | Forward signal from SSA to cavity - amplitude | |||||||||||||||
| R | FWDPWR | Forward signal from SSA to cavity - power | |||||||||||||||
| R | REV | Reverse signal from cavity - amplitude | |||||||||||||||
| R | REVPWR | Reverse signal from cavity - power | |||||||||||||||
| R/W | ALEM | LEM computed integrated RF amplitude (MV) per cavity and per cryomodule | |||||||||||||||
| R/W | PLEM | LEM computed phase (deg) | |||||||||||||||
| R/W | EGLEM | LEM computed energy gain (MeV) | |||||||||||||||
| R/W | CHLEM | LEM computed chirp (MeV) | |||||||||||||||
| R | FUDG | Beam-based scale factor applied to cavity probe amplitude readback. Nominal value of 1. | |||||||||||||||
| R | L | Cavity length | |||||||||||||||
| R | FREQ | Cavity frequency | |||||||||||||||
| R | IMPED | Shunt impedance | |||||||||||||||
| In Progress/Tentative | |||||||||||||||||
| RFREADY | Status of RF controls, (Ready, Not Ready) set to ready when control loops are closed and RF is continuous. Or will we ever run with pulsed RF? | ||||||||||||||||
STAT | Status bits in software (define the bits) | ||||||||||||||||
| HSTA | Hardware status | ||||||||||||||||
| DFDES | Cavity detuning setpoint (Hz) | ||||||||||||||||
| ERRWF | Error waveforms corresponding to waveforms above, captured and put in a separate buffer when a fault is detected (degrees or MV) | ||||||||||||||||
| PZWF | Waveforms from tuner piezo motors, useful for finding microphonics. Units TBD. | ||||||||||||||||
| Latching SRF Interlocks - In Progress/Tentative | |||||||||||||||||
| R | QUENCH_FLT |
Cavity quench fault, from interlock chassis. Current status, latched status, and reset command | |||||||||||||||
| R | QUENCH_LTCH | ||||||||||||||||
| W | QUENCH_RESET | ||||||||||||||||
| R | CPLRVAC_FLT |
Coupler vacuum fault, from interlock chassis. Current status, latched status, and reset command | |||||||||||||||
| R | CPLRVAC_LTCH | ||||||||||||||||
| W | CPLRVAC_RESET | ||||||||||||||||
| R | BMLNVAC_FLT |
Beamline vacuum fault, from interlock chassis. Current status, latched status, and reset command | |||||||||||||||
| R | BMLNVAC_LTCH | ||||||||||||||||
| W | BMLNVAC_RESET | ||||||||||||||||
| R | STEPTEMP_FLT |
Stepper temperature fault, from interlock chassis. Current status, latched status, and reset command | |||||||||||||||
| R | STEPTEMP_LTCH | ||||||||||||||||
| W | STEPTEMP_RESET | ||||||||||||||||
| R | CPLRTEMP_FLT |
Coupler temperature fault, from interlock chassis. Current status, latched status, and reset command | |||||||||||||||
| R | CPLRTEMP_LTCH | ||||||||||||||||
| W | CPLRTEMP_RESET | ||||||||||||||||
| W | INTLK_RESET_ALL | Reset all latched faults from interlock chassis | |||||||||||||||
| Non-Latching SRF Interlocks (These are per-cryomodule, not per-cavity) - In Progress/Tentative | |||||||||||||||||
| R | HEPRES_FLT | Helium pressure fault, from cryo system PLC | |||||||||||||||
| R | HELEVEL_FLT | Helium level fault, from cryo system PLC | |||||||||||||||
| R | RFHEARTBEAT_FLT | Cryo receives RF heartbeat, from cryo system PLC | |||||||||||||||
| R | CRYOHEARTBEAT_FLT | Cryo PLC heartbeat fault. Generated by RF software when cryo data stops updating or updates too slowly | |||||||||||||||
| Interlock Thresholds - In Progress/Tentative | |||||||||||||||||
| R/W | CPLRVAC_THRES_L | ||||||||||||||||
| R/W | CPLRVAC_THRES_H | ||||||||||||||||
| R/W | BMLNVAC_THRES_L | ||||||||||||||||
| R/W | BMLNVAC_THRES_H | ||||||||||||||||
| R/W | STEPTEMP_THRES_L | ||||||||||||||||
| R/W | STEPTEMP_THRES_H | ||||||||||||||||
| R/W | CPLRTEMP_THRES_L | ||||||||||||||||
| R/W | CPLRTEMP_THRES_H | ||||||||||||||||
| Cavity Ramp-Up and Calibration Output | |||||||||||||||||
| R | QLOADED | Loaded Q | |||||||||||||||
| R | CAV_CONST | Cavity calibration constant (later will be merged with CAV:CAL_SCALE) | |||||||||||||||
| R | LDCOEF | Lorentz detuning | |||||||||||||||
| R | BCOEFM | State space B coefficient magnitude | |||||||||||||||
| R | BCOEFP | State space B coefficient phase | |||||||||||||||
| R | SSA:SLOPE | SSA slope | |||||||||||||||
| R | SSA:PED | SSA pedestal | |||||||||||||||
| R | SSA:MINX | SSA min X | |||||||||||||||
| Waveform Signals | |||||||||||||||||
The PVs below will be provided for each waveform signal. Each cavity has the following waveform signals:
| |||||||||||||||||
| Waveform | R | <SIG>:AWF | Signal amplitude waveform | ||||||||||||||
Statistics | R | <SIG>:AMEAN | Mean of <SIG>:AF | ||||||||||||||
| R | <SIG>:ASTD | Standard deviation of <SIG>:AWF | |||||||||||||||
| R | <SIG>:AMIN | Minimum of <SIG>:AF | |||||||||||||||
| R | <SIG>:AMAX | Maximum of <SIG>:AWF | |||||||||||||||
| Waveform | R | <SIG>:PWF | Signal phase waveform | ||||||||||||||
| Statistics | R | <SIG>:PMEAN | Mean of <SIG>:PWF | ||||||||||||||
| R | <SIG>:PSTD | Standard deviation of <SIG>:PWF | |||||||||||||||
| R | <SIG>:PMIN | Minimum of <SIG>:PWF | |||||||||||||||
| R | <SIG>:PMAX | Maximum of <SIG>:PWF | |||||||||||||||
| Waveform | R | <SIG>:PWRWF | Signal power waveform | ||||||||||||||
| Statistics | R | <SIG>:PWRMEAN | Mean of <SIG>:PWRTRACE | ||||||||||||||
| R | <SIG>:PWRSTD | Standard deviation of <SIG>:PWRWF | |||||||||||||||
| R | <SIG>:PWRMIN | Minimum of <SIG>:PWRWF | |||||||||||||||
| R | <SIG>:PWRMAX | Maximum of <SIG>:PWRWF | |||||||||||||||
| Waveform | R | <SIG>:ITWF | Signal I waveform | ||||||||||||||
| Waveform | R | <SIG>:QTWF | Signal Q waveform | ||||||||||||||
By default, these should be write-protected during operation
| Name | Description | |
|---|---|---|
| (from Chris Adolfsen. Garth wonders should this be a calibration attribute rather than physics interface?) Slow tuner start-up position prior to rf turn on - with the piezo voltages zeroed, the cavity would be tuned close to 1.3 GHz after the operating gradient is established - thus the initial detuning with rf off relative to 1.3 GHz is K*(operating gradient)^2 | ||
| (from Chris Adolfsen. Garth wonders should this be a calibration attribute rather than physics interface?) Slow tuner park position - this is the position the tuner would be set if one wants to detune the cavity so it does not interact with the beam. | ||
| Q0 | Q0 measurement from partner labs, delivered with the cryomodule | |
| Qext | Qext measured in-situ (last measurement – used to calibrate cavity probe signal based on discharge power) | |
| LFD | Lorentz Force Detuning K factor(Hz/(MV/m)^2) measured in-situ | |
| Calibration of the slow tuner (Hz/step) measured in-situ | ||
| Calibration of the piezo tuners (Hz/volt) measured in-situ | ||
| Signal calibration. The PVs below will be provided for FWD, REV, DRV signals. | ||
| Measured values | ||
| <SIG>:CAL_ADC_10DBM | R/W | ADC counts at 10 dBm. EPICS software uses this to calculate RF power at full scale. |
| <SIG>:CAL_LOSS_CABLE | R/W | Measured cable losses used in signal calibration. Positive value in dB. |
| <SIG>:CAL_LOSS_CPLR | R/W | Measured coupler loss used in signal calibration. Positive value in dB. |
| <SIG>:CAL_LOSS_ATTEN | R/W | Fixed attenuator used in signal calibration. Positive value in dB. |
| <SIG>:CAL_LOSS_OTHER | R/W | Unattributed measured loss used in signal calibration. Positive value in dB. |
| EPICS-calculated values | ||
| <SIG>:CAL_REF_PWR | R | RF power at ADC full scale. In dBm. Analogous PVs exist for reverse and drive (aka loopback) signals. |
| <SIG>:CAL_LOSS_TOTAL | R | Total (of cable, coupler, atten, other) loss used in signal calibration. Positive value in dB. |
| <SIG>:SCALE | R | Calibration scale factor to convert raw ADC counts to amplitude in sqrt(Watts). Calculated internally by RF software, based on system losses and ADC power at full scale. |
| Signal calibration for Cavity Probe (CAV) | ||
| CAV:CAL_SCALE | R/W | Calibration scale factor to convert cavity probe raw ADC counts to amplitude in MV. Calculated by LLRF calibration sequence. See CAV:SCALE for more info. |
| CAV:SCALE | R | Calibration scale factor to convert cavity probe raw ADC counts to amplitude in MV. Is equal to product of CAV:CAL_SCALE and beam-based FUDG scale factor. |
| Chassis and ADC scale factor, or polynomial coefficients. From lab measurements of chassis to convert ADC units to physics units | ||
| PI(no D) loop parameters for amplitude and phase loops. Maybe PKp, PKi, GKp, GKi | ||
| Open loop amplitude and phase DAC settings | ||
| Control loop status (open, closed) | ||
| Name | Description |
|---|---|
| V | Chassis power supply voltage |
| T | Chassis board temperature |
| DC | SSA enable/disable internal DC power |
SSA RF enable, how to distinguish from global RF enable? | |
| PzVout | Output voltage to the piezo tuning motor |
| PzHz | Expected tuning change from PzVout |
| Name | Description |
|---|---|
| Firmware MD5 | |
BMB7 board serial # | |
| Digitizer board serial # | |
| Chassis serial # and/or Depot number |
