ProtoDUNE Trigger UpdateUniversity of Pennsylvania

N Barros, J Sensenig, D Rivera

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ProtoDUNE Trigger Update: Outline 12/09/2018 Penn

● Motivation for a trigger update

● Overview of triggering architecture

● Overview of data word format

● Overview of the inputs from the 3 main subsystems

● Overview of triggers

● Trigger details

○ Triggers already in place. . .

● Summary

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ProtoDUNE Trigger Update: Motivation, Triggers! 12/09/2018 Penn

● Starting to trigger on beam and readout the detector with the issued triggers!

● Triggered at ~30Hz (no prescale on CTB1)

● Spikes in fragment rate (red) correspond to spills.

1 CTB = Central Trigger Board

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ProtoDUNE Trigger Update: Brief Trigger Concept 12/09/2018 Penn

N. Barros ● Raw trigger inputs are delayed and reshaped as necessary.

● Low Level Triggers (LLTs) form triggers within a subsystem1.

● High Level Triggers (HLTs) composed of LLTs.

● All LLTs and HLTs are recorded and passed to to the board reader.

● Assertion of HLT results in a command being passed to the timing system specifying the type of trigger, e.g., beam on or cosmic. 1 Subsystems: Beam, Cosmic Ray Tagger (CRT), Photon Detection System (PDS)

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ProtoDUNE Trigger Update: CTB Data Structure 12/09/2018 Penn

N Barros

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ProtoDUNE Trigger Update: CTB Data Structure (cont.) 12/09/2018 Penn

● In addition to the words on the previous slide, there was a word added (above).

● Called Channel Status Word it is generated whenever a HLT trigger word is sent

and is essentially a snapshot of the inputs at the time of the HLT generation.

● Brings word types to 4:

○ High Level Trigger (HLT)○ Low Level Trigger (LLT)○ Channel Status (CS)○ Timestamp (TS)

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ProtoDUNE Trigger Update: Beam Instrumentation Inputs 12/09/2018 Penn

○ (x1) Beam On (Beam Extraction)

○ (x1) BI Trigger Sj & Sk

○ (x1) Si upstream at 687

○ (x2) Cherenkov C1 & C2

○ (x3) Beam Profile X&Y 1,4,5

○ (x1) Beam Profile 1,2,3 x-planes

only (the spectrometer)

- Paola

● NIM signals sent from CRT to trigger board.

● CRT inputs channels are mapped into pixels for more natural trigger formation.

● Example: through-going muon8

ProtoDUNE Trigger Update: CRT1 Trigger Inputs 12/09/2018 Penn

Pixelized!

Flavio

N Barros N Barros

1 Cosmic Ray Tagger

● 24 Trigger inputs from photon system.

● 4 trigger signals per APA● Trigger signal is the

discriminator output after acting on the digitized photon system SiPM signal.

● Generally referred to as the SiPM Signal Processors (SSPs)

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ProtoDUNE Trigger Update: PDS1 Trigger Inputs 12/09/2018 Penn

1 Photon Detection System

● Beam triggers priority due to limited beam time.

● Need flexibility in the trigger since we aren’t completely sure what to expect from

the beam, although can’t do anything/everything.○ Double-edged sword, flexibility makes it easier to lose track of the exact configuration for a given

run.

● Likely the beam particle rate will be higher than the target TPC trigger rate

(~20Hz). ○ Require more of the beam instrumentation to “see” the particle before issuing a trigger.

Compensates for small inefficiencies in beam detectors (e.g., ~5% / Sci-Fi trackers)

○ Might not be true for lower beam energies due to lower rates.

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ProtoDUNE Trigger Update: Beam Triggers Overview 12/09/2018 Penn

Beam ON (during spill)

1. “Less strict” trigger

2. Reconstructable track trigger

3. Medium beam energy pion trigger, cherenkov particle selection

4. Muon halo trigger, with photon system

5. Low beam energy electron trigger, cherenkov particle selection

6. Low beam energy hadron trigger, cherenkov particle selection

Beam OFF

7. Cosmic muon trigger: (high → low, CRT panels), (up → downstream, CRT) and (PDS

on Saleve-side) 11

ProtoDUNE Trigger Update: Triggers 12/09/2018 Penn

● Should give sample of any charged beam particle. (Also requires the beam spill to be On)

○ Doesn’t give information about what particle.● More relaxed trigger requirement 12

ProtoDUNE Trigger Update: (1) Beam Trigger 12/09/2018 Penn

● Should give sample of any charged beam particle (reconstructable track). (Also requires the beam spill to be On)

○ Doesn’t give any information as to what kind of particle.13

ProtoDUNE Trigger Update: (2) Beam Trigger 12/09/2018 Penn

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ProtoDUNE Trigger Update: (3) Beam Trigger 12/09/2018 Penn

● For 3-5 GeV/c beam, indicates a pion in the beamline. (Also requires the beam spill to be On)

○ Using Cherenkov detectors for particle Id 14

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ProtoDUNE Trigger Update: (4) Beam + CRT Trigger 12/09/2018 Penn

Beam On muon halo trigger. Required conditions are:

● Looks for a hit in any pixel enclosed by the red rectangle (x4 CRT pixels/rec.) in coincidence of the US and DS panels. If there are coincident hits between US && DS and . . .

● . . . n hits coincident with CRT on Saleve side SSPs, where n > 2 15

● ADD CRT TRIGGER HERE!

● For the low energy beam, 1-2 GeV/c. (Also requires the beam spill to be On)● Indicates presence of an electron in the beamline.● Likely be used as a veto for early running since we will have mostly electron beam

near the end of the beam schedule. 16

ProtoDUNE Trigger Update: (5) Beam Trigger 12/09/2018 Penn

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● For 1-2 GeV/c beam (Also requires the beam spill to be On)● Indicates a heavy particle in the beamline.

○ Doesn’t say which heavy particle, (p, K, π ?).17

ProtoDUNE Trigger Update: (6) Beam Trigger 12/09/2018 Penn

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ProtoDUNE Trigger Update: (7) CRT Trigger 12/09/2018 Penn

Beam Off cosmic trigger, required conditions are:

● Looks for a hit in any pixel enclosed by the red rectangle (x4 pixels) in both the US and DS panels. If there are coincident hits between US && DS and . . .

● . . .n hits coincident with CRT on Saleve side SSPs, where n > 2 18

● ADD CRT TRIGGER HERE!

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ProtoDUNE Trigger Update: Trigger bit definition 12/09/2018 Penn

● We are currently in commissioning○ These trigger definitions have not been tested exhaustively

○ Prescales, or even list of included channels might need to change

○ The fast pace of commissioning does not allow to implement new trigger blocks

(bits) every time we make any small change

○ Result: The same trigger bit can have a different meaning between 2 runs

● Mitigation strategies:○ Keep track of the CTB configuration (both input mask and trigger masks)

■ Perhaps makes sense to store it with the output?

○ Try to minimize the changes on this definition

■ And try to avoid changes at all once commissioning wraps up

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ProtoDUNE Trigger Update: Take home messages 12/09/2018 Penn

● The CTB has currently 7 triggers implemented○ 6 beam correlated, 1 off beam

● Only one (HLT_2) has been enabled○ Allows to run with reasonable rates to test to sync with different subsystems

(commissioning)

● Exact trigger definition can change, as commissioning progresses○ Unclear how to make the definition available offline

■ Run header metadata, user check on run configuration database, etc

● We will try to keep modifications and differences to a minimum○ Plan to move to an approach of adding new trigger bits once commissioning

stabilizes

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ProtoDUNE Trigger Update: Summary 12/09/2018 Penn

● Triggering the DAQ using SSP and beam inputs.○ Still need synchronization of SSPs and calibration of beam instrumentation.

● 2 CTB raw decoders○ dunetpc v07_05_00 → data product raw::ctb::pdspctb.h.

○ feature branch CTB_OM → histograms of trigger word numbers

● If there are any suggestions on triggers, whether to add or modify the

existing triggers, please let us know as soon as possible!○ Easy to change (i.e., configuration file): multiplicities, channels within a subsystem

○ More difficult change (i.e., firmware): adding LLTs, HLTs

The End

Thanks!

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ProtoDUNE Trigger Update: 12/09/2018 Penn

Backup Slides...

● Caveat, we need to be very cautious to make sure we’re not vetoing good events due to a noise bursts, etc. 23

ProtoDUNE Trigger Update: Beam Trigger “Option” 12/09/2018 Penn

● Select pixels around the beam pipe.● Veto a trigger if the number of CRT hits

near the beam pipe (shaded red region) is greater than n, where n is configurable at runtime.

● Any of the aforementioned beam particle triggers.

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ProtoDUNE Trigger Update: Flavio’s Proposed Triggers 12/09/2018 Penn

✓✓✓

✓

✓

✓ = Implemented Triggers

✓ = Under Development

✓

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ProtoDUNE Trigger Update: Jon Paley’s Proposed Triggers 12/09/2018 Penn

● The condensed version of possible beam triggers from Jon Paley’s suggestions, slides here.

● Some definitions are in the figure to the lower left. Slightly outdated diagram but incldues some definitions for the above triggers. 1 = Included, 0 = Excluded, X = Don’t Care

● Beam triggers priority due to limited beam time.

● Need flexibility since we aren’t completely sure what to expect from the beam,

although can’t do anything.

● Likely the beam particle rate will be higher than the target TPC trigger rate (20Hz?).

Allows more selectiveness with the triggering for beam events, as Flavio pointed

out.○ Might not be true for lower beam energies.

● Beam fiber detector inefficiencies ~5% (slides) and 4 fiber detector inputs to trigger.○ 1-(efficiency)^(no. det) = 1-(0.95)^4 = 18.5% total fiber detector inefficiency (rough estimate, also

some inefficiency in ToF and Cherenkov counters)

○ Requiring all beam detectors will increase the total inefficiency therefore cutting the trigger rate.

○ Requiring all detectors would ensure data from all the fiber detectors included in the trigger. 26

ProtoDUNE Trigger Update: Beam Triggers Overview Expanded 12/09/2018 Penn

● Beam backgrounds from Fluka beam line simulation, slides here.● (!) Veto a beam trigger if there are too many hits on the CRT near the beam plug, i.e.,

if the beam halo is too intense near the beam particle entrance to the TPC. 27

ProtoDUNE Trigger Update: CRT Triggers (!) Use Veto with Caution 12/09/2018 Penn

● Expected beam composition from the ProtoDUNE TDR

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ProtoDUNE Trigger Update: Beam Composition 12/09/2018 Penn