MiniBooNE Trigger Notes

Version 4.0

Applicable for running period from 3/35/2004 ->present

Rex Tayloe, Andrew Green 4/1/2004

Introduction

Find in this document the status of the trigger during the period March 25, 2004 to the present.  See the references listed below for background information. References to particular pieces of C-code are given by name. Find these at the MiniBooNE CVS repository (Reference 5). 

Summary of trigger work done during the March 2004 10-day shutdown:

  1. Addition of zerobias follower event types.  The need to look at events with lower Nhit that DET1 allows motivate the need for these new event types.  The NIM hardware making the E-bits was modified slightly to add another E2 input to take the place of DET1, and to minimize the impact to triggerloop.c.
  2. Solution to trigger latency problem.  I say solution (even though a little latency exists) because latency is no longer the limitation to the trigger software that it once was.  This allows very low rates of latency for follower triggers which come after beam/strobe events very close in time.  Before the fix, latency rates for follower events were in the tens of percent, now they are <1/10000 (over 3 orders of magnitude improvement).

Trigger Hardware Settings:

Detector comparator settings:

Detector (DET) Trigger bit

Setting 

VETO Trigger bit 

Setting

DET1

# tank hits >= 10

VETO1

# veto hits >= 6

DET2

# tank hits >= 24

VETO2

# veto hits >= 4

DET3

# tank hits >= 200


DET4

# tank hits >= 100



DET5

# tank hits >= 60


Notes:


Definition of External Inputs to the trigger

The External inputs, or "E bits," are formed using discriminator and logic modules in a NIM crate above the trigger (VME) crate. The NIM logic pulses were set to be >=150ns and routed to the 4 BNC inputs of the trigger memory card.

External Trigger Input
Explanation

E1

Beam on target. IRM signal is $ID & $1F

E2 2.01 Hz Strobe (pulser), Debuncher, and Follower event.  The table "Strobe & Debuncher" below explains how this bit is shared.
E3 calibration: used for CALIB_LASER, CALIB_CUBE, CALIB_TRACKER, and  CALIB_BEAM event types.  The table below explains how this bit is shared by the calibration event types.
E4 NIM Hardware OR of E1-E3.   Causes a stack load on the trigger FIFO.

Notes:


Calibration activity types (using the E3 input to trigger):

Calibration Activity

Width of E3 pulse

Times E3 asserted to trig FIFO

Explanation

CALIB_CUBE

150ns

1 or 2

Prescaled cube trigger

CALIB_LASER

450ns

4 or 5

Simple laser event.  The laser is veto'd around beam & strobe events 5 u-sec before, and 30 ms after the event.

CALIB_TRACKER

650ns

6 or 7

Prescaled cube + 4-plane tracker coincidence OR just tracker

CALIB_BEAM

850ns

8 or 9

Laser in time with non-M'BooNE Booster shot

Notes:



Shared Inputs to E2:

Activity

Width of E2 pulse

Times E2 asserted to trig FIFO

Explanation

FOLLOWER
150ns
1 or 2
Single pulse is delayed 20u-sec from a beam or a strobe pulse.  This is meant to force a stack load so that triggerloop.c will produce the zerobias follower events explained below.

STROBE

350ns

3 or 4

Strobe event from the 2.01 Hz Pulser

DEBUNCHER

550ns

5 or 6

Debuncher event from IRM: $81 event (injection to target at anti-proton source.)

Notes:

Trigger Software

Trigger History & Activity timers:

  1. Added trigger history data to the trigger's component of the data going into the data-stream.  The trigger history data consists of three components:
    1. The past 90 entries into the trigger stack (FIFO).  This is a running record of all inputs into the trigger, and their associated times.
    2. The past 4 trigger "events."  These have the same form as the FIFO entries, except the various inputs are ORed  within a contiguous group of activity in time. 
    3. 24 Activity timers.  These use information from the trigger inputs as well.  Timers such as "when was the last beam trigger?" or "when was the last cosmic?"
    4. The anti-proton debuncher event (IRM signal "81") causes one of the activity timers, ACT_DT_DEBUNCHER (see TriggerActivityChunk), to be reset.  This timer measures the time since the last anti-proton debuncher event fired.  There currently is no actual debuncher event, but the activity timers are available in all event types.  Neutrinos emanating from the debucher would be fairly energetic, and would be expected to land in a "Big Nu" event.
  2. Trigger, timing & history data made available via AnalysisFramework chunks in the CalibrateHits package, DAQbitFieldsChunk, and TriggerActivityChunk.

The Trigger Loop:

Using the above bits and appropriate logic within the trigger code, these "windows" and "holdoffs" are created in the trigger software

Trigger Windows/Holdoffs:

Window name

Abbrev.

Definition (logical). T(*) indicates time since this activity in the trigger in microseconds.

Explanation

"beam holdoff"

BH

T(E1) <= 20

Holdoff of all other triggers during beam event.

"Michel window"

MW

3 <= T(DET4 .and. VETO1) <= 15

A cosmic ray candiate has occured in a window. Look for Michel electrons.

"Laser holdoff"

LH

T(CALIB_LASER) <= 2

No laser event 200 ns prior.

"SuperNova holdoff"

SNH

T(DET4 .or. VETO1) <= 15 .or. LH

A cosmic ray or calibration laser event has occured in recent past. Holdoff SN triggers.

"Gamma/beta holdoff"

GBH

T(DET2 .and. VETO2) <= 15

A cosmic ray has occured in recent past. Holdoff Gamma and Beta triggers.

"Beam nu candidate"

BNuC

3.6 <= T(DET2) <= 8.6 within Beam event with respect to the event origin.

A nu candidate in beam on window. Use for beta/gamma windows.

"Strobe nu candidate"

SNuC

3.6 <= T(DET2) <= 8.6 within Strobe event with respect to the event origin.

A nu candidate in  simulated "beam" window. Use for beta/gamma windows for accidentals.

"beam gamma window"

BGW

54 < T(BNuC) <= 1000 ( note: the left limit is applied only when we are taking zerobias evens)

A gamma after a beam nu candidate.

"beam gamma zerobias window"
BZBW
T(BNuC) <= 54
Activates zerobias follower events to follow immeidate after the beam event with activity in the beam timing window, BNuC.

"strobe gamma window"

SGW

54 <= T(SNuC) <= 1000 ( note: the left limit is applied only when we are taking zerobias evens)

A gamma after a strobe nu candidate.

"strobe gamma zerobias window" SZBW
T(SNuC) <= 54 Activates zerobias follower events to follow immeidate after the strobe event with activity in the simulated "beam" timing window, SNuC.

"beam beta window"

BBW

1000 <= T(BNuC) <= 30000

A beta after a beam nu candidate.

"strobe beta window"

SBW

1000 <= T(SNuC) <= 30000

A beta after a strobe nu candidate.

"calibration cube window"

CalCuW

0.4 <= T(CALIB_CUBE) <= 0.8

Account for time delay between cube trigger (real time) and associated DET/VETO activity (sum PMT system takes ~6 cycles to compute detector sum).

Notes:


Event Types:

Trigger event type

Trigger name

Condition (! = .not.)

Base TSA offset

# of TSAs broadcast

Explanation

1

beam

!BH .and. E1

0

192

Neutrino beam on target signal. This signal comes 5&mu;s before beam is on target so no addtional offset is needed.

2

strobe

!BH .and. STROBE (see "Shared Inputs to E2" table)

0

192

Pulser signal. Everything else just like beam triggers.

4

Michel

!BH .and. MW .and. !VETO1 .and. DET2

-160

192

Muon decay Michel electrons. The TSA window is large enough to contain the parent (cosmic-ray) muon.

5

SuperNova

!BH .and. !SNH .and. !VETO1 .and. DET5

0

32

SuperNova candidate.

6

Tank

!BH .and. DET1

-96

192

Minimum bias tank tube trigger.

7

Veto

!BH .and. VETO1

-96

192

Minimum bias veto tube trigger.

8

calibration: laser

!BH .and. CALIB_LASER

6

96

laser event

9

calibration: beam

!BH .and. CALIB_BEAM

0

96

Laser in time with non-MiniBooNE Booster shot.

10

calibration: cube

!BH .and. CalCuW .and. DET4

-5

128

Cube in time with DET4 tank hits.

11

calibration: tracker

!BH .and. CALIB_TRACKER

-4

128

muon tracker 4-plane coincidence, plus cube (this varies)

12

beam gamma

!GBH .and. BGW .and. DET1 .and. !DET4 .and. !VETO2

0

32

gamma candidate following a beam nu candidate

13

beam beta

!GBH .and. BBW .and. DET2 .and. !VETO2

0

32

beta candidate following a beam nu candidate

14

strobe gamma

!GBH .and. SGW .and. DET1 .and. !DET4 .and. !VETO2

0

32

gamma candidate following a strobe nu candidate

15

strobe beta

!GBH .and. SBW .and. DET2 .and. !VETO2

0

32

beta candidate following a strobe nu candidate

16

big nu

!LH.and.DET3.and.!VETO1

0

192

tank hits > 200, no veto, no laser, no beam. Used for debuncher events, high-energy neutrinos from the environment, veto efficiency.

17
beam gamma zerobias

BZBW.and.FOLLOWER  (see "Shared Inputs to E2" table)
0
192
Immediately follows the beam event in time.  A configurable number of these events will be produced for every beam event containing activity within the neutrino candidate window.
18
strobe gamma zerobias
SZBW.and.FOLLOWER  (see "Shared Inputs to E2" table) 0
192
Same configuration as the beam version, but follows strobe events instead.  This is means as a background-measuring event.

Notes:

References

  1. LSND NIM paper: NIM A388, 149, '97.

  2. miniBooNE TDR

  3. "Data Acquistion Electronics and Programmer's Model, BooNE TN-038, Vern Sanberg, 2001.

  4. Slides from MiniBooNE analysis meeting, Rex Tayloe, 2/13/02, "http://www-boone.fnal.gov/software_and_analysis/meetings/02-13-02/minutes_02-13-02.html .

  5. MiniBooNE CVS Repository, Trigger Source Code, http://cdcvs0.fnal.gov/cgi-bin/public-cvs/cvsweb-public.cgi/miniboone/DAQ/target/trigger/src/" , and http://cdcvs0.fnal.gov/cgi-bin/public-cvs/cvsweb-public.cgi/miniboone/DAQ/share/src/"


Rex Tayloe, Andrew Green

Last modified: Feb 13 2004