# D0 RunIIb Commissioning {#d0-runiib-commissioning .unnumbered}

**August 8, 2003**

# Introduction

The D0 Run Iib upgrade consists of a trigger upgrade and a new silicon
detector. In this document, we go through the commissioning plans for
the upgrade to reach taking physics quality data. The starting point is
the installation and technical commissioning plans pre-beam. This
document also discusses post-beam commissioning with data.

# Overview of Upgrades

In this section we give a brief overview of the upgrades as they affect
commissioning plans. An in depth description of the upgrades is given in
\[footnote RunIIb TDR\].

## Silicon Detector upgrade

The silicon detector upgrade was designed to be more radiation hard than
the Run IIa silicon detector and to replace the Iia detector after an
integrated luminosity of approximately 2 fb-1. Subsequent studies of the
current detector have indicated that its performance will be seriously
compromised by 2006 even neglecting radiation damage \[footnote Breese's
note\]. In addition to being radiation hard, the new detector is
substantially better performant due to improved geometry and
electronics.

The D0 silicon microstrip tracker (SMT) provides the precision tracking
and secondary vertex tagging capability essential to the high pt physics
and search programs proposed for Run IIa, and the detector is designed
to accommodate the integrated luminosity the 2 fb-1 of that run.   It
has long been recognized that the physics potential of the Tevatron
collider program can be significantly enhanced as substantially larger
integrated luminosities are achieved (Run IIb).   However, the
performance of the current SMT is anticipated to be significantly
compromised as a result of radiation damage by the time it is exposed to
an integrated luminosity of 3.6+-1.8 fb-1. (It is currently estimated
that 100% of the channels on the inner layer of the current detector
will be dead by 4.9+-2.5 fb-1.)  So, to be in a position to take full
advantage of the large integrated luminosities expected from the
Tevatron prior to the LHC turn-on, the D0 collaboration is building an
upgraded detector, which is currently scheduled to be installed in 2006.

The upgraded detector is designed to optimize its physics performance
while addressing the various other boundary conditions (cost, schedule,
available real estate\...), and builds upon the experience generated
from the Run IIa detector.  To address the tight time constraints
involved, the adopted design is modular and uses a minimum of different
types of components.   The upgraded detector is designed to be installed
without rolling the D0 detector from the collision hall, and no elements
are supported from the beam pipe.  To achieve this in-situ installation,
the upgraded silicon detector will leave the Silicon Detector facility
as two independent barrel assemblies that will be joined at D0 during
the installation.  The commissioning time should be minimized by
re-using most of the higher level parts of the current detector readout
system.

### New detector geometry/sensors

The new detector consists of 2304 radiation hard silicon sensors, and is
designed to withstand an integrated luminosity of 15 fb-1. The detector
uses only single-sided silicon, and there are only three types of
sensors in the detector.  The detector consists of six layers of silicon
in a barrel geometry, with the innermost layer at a radius of 18 mm from
the beam centerline, and the outermost layer at a radius of 163mm.   The
new geometry has more layers, and also has detectors \~8 mm closer to
the interaction region (thereby improving the impact parameter
resolution). The two innermost layers will be axial only, while the
outer layers will provide both axial and small angle stereo
measurements.   The sensors on the innermost layer have a 50 micron
readout pitch while the sensors on the second layer have a 58 micron
readout pitch.  The sensors used for the outer four layers have a 60
micron readout pitch.  All sensors have intermediate strips. These two
innermost layers will be mounted directly on integrated carbon fiber
support structures which have cooling tubes integrated into the support
structures.  The outer sensors will be mounted on assemblies known as
staves, which provide the mechanical support and cooling for these
sensors. The sensors on one side of the stave will be oriented with
strips parallel to the beam, while on the opposite side of the stave the
sensors will be mounted to achieve small angle stereo measurements.  The
completed detector has 168 staves.

.

### New Readout

The readout of the silicon sensors employs 7440 SVX4 chips, which are
being jointly developed by LBL and Fermilab for CDF and D0.  Each SVX4
chip consists of 128 input channels.  Each individual channel integrates
the input charge from a silicon strip, and transfers the charge to a
switched capacitor array referred to as the pipeline (the pipeline is 46
cells deep).  When a level 1 trigger is received, the appropriate charge
is digitized by the SVX4 chip, and the digitized results are propagated
to the data acquisition system.

The SVX4 chip is generated in 0.25 micron technology and is
intrinsically radiation hard.   The SVX4 chips will be mounted on
ceramic hybrids.  For the outer five layers, the hybrids will be mounted
directly on the silicon sensors.  To reduce costs and minimize the
commissioning time, the SVX4 chip will be readout in SVX2 mode so that
the higher level readout can rely upon the sequencers, sequencer
controllers, VME Readout Buffers, and VME Readout Buffer Controllers
currently in use in Run IIa. (Adapter cards which convert single ended
signals to differential signals and are mounted on support horseshoes on
the central calorimeter must be replaced, and the interface boards will
also need to be modified.)   The changes to the readout and the geometry
of the detector will need to be taken into account in the software that
supports operation, readout, calibration and interpretation of the data.

## Trigger Upgrade

The trigger upgrade consists of upgrades to both Level 1 and Level 2
triggers. At level 1 we plan to replace the calorimeter trigger with a
new calorimeter trigger, upgrade the exisiting central track trigger and
add a calorimeter-track matching trigger.

At level 2 we will upgrade the Silicon Track Trigger to use with the new
silicon detector and upgrade the level 2 beta boards with more powerful
processors to handle the high luminosities.

### Level 1 Trigger

####  Calorimeter Trigger

The upgrade provides

-   improved capability to assign calorimeter energy deposits to the
    correct beam crossing and rejection of pileup using digital
    filtering,

-   sharper turn-on curves for jets and EM object using a sliding window
    algorithm

-   the ability to

    -   identify hadronic tau decay candidates at level 1 through narrow
        jet profiles

    -   make shape and isolation cuts on EM objects

    -   properly include energy in the ICR when calculating jet energies
        and missing ET

    -   make topological trigger requirements at level 1 (acoplanarity,
        etc.)

####  CTT

Upgrade of logic, processing power to use full granularity and
resolution of individual CFT fibers instead of doublets as are currently
used. This is needed because of the increase in fake rates as luminosity
(occupancy) increases. This becomes a problem at mean #interactions
\~3.5-4.

####  Cal-Track Match

Matches tracks in phi to calorimeter objects (EM, jet, tau) with a
precision of about 0.2 radians. The design is based on the current L1Muo
trigger (that matches tracks with muons) and used modified MTCxx cards
with new flavor boards (MTFB) to before the

cal-track match. It relies on the upgraded L1Cal to provide the
calorimeter object for matching, and it benefits from the upgrade of the
L1CTT, which provides the tracks.

Electron candidates are identified by a match between a track and an EM
object. Hadronic tau decays are identified by matches between tracks and
hadronic energy in the calorimeter.

### L2 Trigger

####  L2 Beta Processors

The upgrade consists of augmenting and replacing the Run 2a L2 Beta
trigger processors with more powerful processors which will be available
at the time. Since basic tools like jet clustering are moved upstream to
Level1 Cal, Level 2 will have to execute more sophisticated algorithms
to maintain rejection on the richer sample provided by Level 1.

#### L2 Silicon Track Trigger

This trigger is needed for the upgraded silicon detector. Basically
adding additional copies of boards to current trigger. (one additional
STC and VTM per crate). Also add\'l link transmitters and receivers.
Firmware upgrades.

### Online System

The online system upgrade consists of ....

# Installation and Technical Commissioning Plan

The installation plan includes installing the physical detector and
trigger upgrades. Technical commissioning means testing that all chains
work fully integrated with each other (using e.g. pulsers,etc). Physics
commissioning will refer to additional steps needed to ensure we are
collecting publication quality data.

## Silicon

The readout chain from sequencer on exists for the detector. It is
crucial to exercise the readout of detector through the interface card
and the normal chain of the readout from SiDet, ahead of installation.
Exercise unpacking using this data. Data must be sent to online system
through the network.

The new silicon detector will have new geometry, which means new
unpacking and reconstruction software. The detector is all new up to and
including the SVX4 readout chips. However the SVX4 is read out in SVX2
mode to make the rest of the readout compatible with the existing Run
Iia readout. So the readout chain chain from adaptor card downstream
will not be replaced . There are an additional 250k readout channels
with the new detector and the sequencer boards will need to be
reprogrammed. In addition some minor modifications to the interface
boards (about 200 per board) will be necessary.

All of the installation and modifications are detailed in the current
installation shedule, and assuming 2 shifts, the installation will take
4 months in total. This time includes 2 weeks of technical commissioning
for each quadrant with a total time of 5 weeks.

During the technical commissioning, all of the electrical connections
for the silicon detector are made and checked. Testing will proceed on a
quadrant-by-quadrant basis. For each adapter card in a quadrant, before
the twisted-pair cable is connected to the adapter cards, the
twisted-pair cable + junction card + digital cable + sensor is tested.
Then the adapter card + 80-conductor cable + interface board is tested.
The radiation monitor cables are connected, and then the twisted-pair
cable is connected to the adapter card and the full readout chain is
tested. The temperature monitoring cables are also connected.

Commission Online Readout Software (4 weeks total time) consists of the
following steps:

**Demonstrate multiple crate downloading and calibration(2w)**: install
and verify the functionality of the monitoring and downloading software
needed for the operation of the silicon system at DAB. This begins when
a readout crate is fully supported (i.e. when one quadrant of the
detector is commissioned).

**Demonstrate data unpacking for two SMT crates (1w):** install and
verify the functionality of the software (electronics to physics
addressing) needed for the operation of the silicon system at DAB. Much
of the software will have been created for the fabrication of the
silicon system at SiDet, so the effort required is largely verification
at DAB that the code is functional when more than one readout crate is
involved.

**Demonstrate data unpacking for all SMT crates(1w)** install and verify
the functionality of the software (electronics to physics addressing)
needed for the operation of the full silicon system at DAB. This task
can begin as soon as all quadrants of silicon become functional. Much of
the software will have been created for the fabrication of the silicon
system at SiDet, so the effort required is largely verification at DAB
that the code is functional when all readout crates are involved.

**Demonstrate SMT Examine package with multiple crates readout (2w)**
This task installs and verifies the functionality of the L3/offline
software needed for the operation of the silicon system at DAB. This
effort is primarily based on verifying the proper function of
well-defined but substantial modifications made to the Run IIa software.

**Verify SMT mapping using Examine Package (1w)** install and verify the
functionality of the L3/offline software needed for the operation of the
silicon system at DAB. This effort is primarily based on verifying the
proper function of well-defined but substantial modifications made to
the Run IIa software, when all crates can be operated.

## Trigger

### Level 1 Trigger

####  Calorimeter Trigger

L1 Cal trigger upgrade consists of replacing current L1 Cal trigger, but
using the same calormeter pickoff signals, L1 framework, L2/L3 data and
clock, timing and control systems.

The main elements of the new L1 Cal trigger are:

ADC Digital Filter Boards (ADF) (80 in total, 4 VME crates)

ADF Timing Fanout Card (1)

Trigger Alg. Boards (10 boards, lots of firmware)

Global Alg. Boards (2 boards, lots of firmware)

These new electronics will be in 2-3 racks of VME crates, replacing
current ADC and logic cards located in 10 racks.

The total time for installation is 7.2 weeks, which includes 2 weeks of
technical commissioning. (Verify the proper functioning (timing,
verification of outputs and decisions) in the itegrated trigger system
with pulser runs, cosmic rays, etc. The task duration assumes all racks
have received preliminary commissioning before the shutdown. This will
be done in the test setup on the sidewalk that is already being set up.

The plan is to pre-commission the entire L1 Cal on the sidewalk before
the installation shutdown. The pre-commissioning will be able to test
all ADF, TAB, and GAB cards, and their interaction with the Trigger
Framework. This includes testing all of the cable connections between
the ADF system and the GAB system. The inputs of all of the ADF cards
will be tested with a wave-form generator being designed at Fermilab. It
addition, the specially designed analog splitter cards (one of which has
already been installed and tested) can be used to send a few real
calorimeter signals to the new L1cal while the old L1cal is still
running undisturbed.

The part that can be tested only after installation is the connection of
the 1280 BLS cables from the calorimeter to the ADF cards, so this will
be the main emphasis of the post-installation technical commissioning.

####  Central Track Trigger (CTT)

Upgrade consists of replacing the existing 80 DFEA daughter boards with
new ones with larger FPGA\'s and reprogramming the track trigger
algorithm.

Total installation time is 8.8 weeks which includes 6 weeks of technical
commissioning. Technical commissioning consists of verifying all inputs
from the AFE and SCL, verifying ouputs to L1 Muon, L2, L3, and debugging
the trigger system with the full D0 DAQ system.

The new DFEA daughter cards are designed to be completely backwards
compatible, so that even before the end of Run 2a, a new pair of
daughter cards could be swapped for an old pair during a short (few
hour) access. The new daughter cards can be configured to execute the
same algorithm as the old cards, so that Run 2a physics operation could
continue with some mixture of new and old daughter cards. The new
algorithms can be downloaded remotely, so special runs could be taken
with the new algorithm to test them directly in Run 2a. Since each DFEA
card corresponds to a specific 4.5 degree azimuthal region, these
special runs could be used to check efficiencies and turn-on curves
using real Run 2a data.

The \"CTT examine\" program runs online whenever are taking data to
check the quality of the CTT data. One of the checks that it performs is
to compare the tracks found by the CTT with those data are expected
based on a simulation of the CTT with the CFT data as input. This gives
an immediate check for each of the 80 trigger sector and each of the
four p_T bins that the hardware is doing exactly what you expect. The
only modification that is required to test the Run 2b CTt is to load the
Run 2b algorithms into the simulator.

####  Cal-Track Match

Installation plan includes 4 weeks of technical commissioning: System
tests including establishing beginning of turn (BOT) trigger,
calorimeter-only triggers, CFT only triggers, simulator-data
certification with noise, pulsers, and cosmic rays (no beam).

In Run2a, the equivalent system tests for Level 1 muon trigger took six
months with three physicists (full time). The cal-trk trigger is
expected to go faster because it is approximately one sixth the size: 2
physicists working full time for 8 weeks. We are planning to work 2
shifts / day, which will mean 4 physicists working full time for 4
weeks.

For the Level 1 Cal-Track Match trigger, there are basically 4 pieces to
commission:

1.  inputs

2.  output to Trigger Framework

3.  output to Level 2 and Level 3 triggers

4.  trigger algorithms

The general plan is to claim space in mch1 and begin filling it as soon
as crates and cards are available. We already have a crate in mch1 that
is used by the fps, however they have not supplied any inputs so in
theory we can use this crate for testing if they still are not ready.

1.  inputs

during the fall '03 shutdown we will install some/all of the cables from
the L1 CTT to L1 cal-track in MCH1

We test inputs via a bot or \"beginning of turn\" trigger. When all
input fifo\'s become not empty, trigger processing begins. We use this
trigger which occurs on the first crossing in order to check inputs
(among other things). Any problem with any input will cause the trigger
rate of the bot to read something other than 47712 hz. In Run Iia, we
use this daily in monitoring l1mu inputs from l1ctt and muon fe\'s.

This would establish an input source that is well-known (since we
already use the inputs for l1mu). We will also run spare cables from a
pdt and scintillator counter to have other known sources. We will
commission the inputs from l1cal whenever they become available.

2.  output to the trigger framework

As mentioned above, one of the first and most important triggers to be
established is the bot. The trigger logic for this trigger is very
simple: we will use the bot trigger to establish communication with the
trigger framework. Basically an oscilloscope is all that is needed for
this part of the commissioning.

3.  outputs to l2 and l3

One problem here is that l1mu outputs to l2 have not even been
commissioned fully. We must decide where to send the l2 outputs from
l1cal-track. The l3 outputs from l1cal-track are sent to an mrc card
that is readout into the data stream. This section (output to l2 and l3)
is not being changed on the mtcm card so hopefully little commissioning
is necessary. l2 and l3 messages themselves are script driven hence
making changes from l1mu to l1cal-track is easy and straightforward.
Commissioning will be done first using online event dumps and later in
offline analysis. We will begin work this summer 2003 including
l1cal-track data into the data stream. This can be done during run2a. We
only need to identify the crate location for an mrc card.

4.  trigger algorithms

This is part of the physics commissioning (below).

### Level 2 Trigger

#### L2 Beta

The new L2 Beta hardware for Run IIb consists of 12 new processors to
replace the 12 most heavily-loaded Beta processors in the L2 system.

All of the hardware and firmware is tested in advance in L2 test crates.
The installation of the new processors in the real L2 crates is a simple
swap of a VME card, along with any necessary code releases.

The new processors can be added with no significant downtime for the
data acquisition and trigger. Processors can be run in \"shadow mode\"
when they are first installed, so that the results of their trigger
algorithms are recorded with each event, while they do not actually
influence the trigger decision. This procedure is well-developed from
the replacement of the Alpha processors with the first-generation Beta
processors in Run IIa. The replacement can even be done near the end of
Run IIa without disturbing the data-taking conditions.

Two weeks have been allocated for technical commissioning of the Run IIb
L2 Beta processors, but even this could largely be accomplished while
the experiment is running.

#### L2 Silicon Track Trigger

The Run IIb SMT has more layers than the Run IIa SMT, so the STT upgrade
consists of adding additional hardware to be able to include additional
silicon layers in the L2 trigger. This is accomplished by adding
additional copies of some of the STT modules: additional Silicon Track
Cards (STC\'s), VME Transition Modules (VTM), Track Fitting Cards
(TFC\'s), plus additional link transmitters, receivers, splitters and
fibers. The STT firmware must also be upgraded for the new SMT geometry.

Aside from running about 150 new optical fibers, the installation of the
STT upgrade involves plugging VME cards into existing crates.

Technical commissioning consists of verifying that data are properly
received from the inputs and transmitted through the system. The
splitters can be tested in advance of the shutdown, but other
connections can be installed and tested only after the Run IIa STT is
decommissioned. During technical commissioning, test data is sent
through the system to test the connections and the tables for channel
map. To complete this technical commissioning, it is important to be
able to get test data from the SMT sequencers independent of the HDI\'s,
so that the STT commissioning can proceed in parallel with the
installation of the SMT itself. For initial system tests, inputs are
needed from one complete 30-degree wedge, plus its associated overlap
channels. Twelve weeks are allocated for this stage of commissioning,
but access to the collision hall is required only during the first xx
weeks.

The final physics commissioning of the detector cannot be completed
without actual beam data from the SMT and CTT (see below)

### Online System

The commissioning of most of the Run IIb computing elements will proceed
either in parallel or parasitically to the operation of the existing
system. The main parts that will proceed in parallel are:

-   New DAQ host system - basically, the location of the data logger and
    the accompanying data buffer disks

-   New File Server system - which holds user and code areas

-   New Database Server system - for ORACLE configuration,

-   calibration, run history, etc databases

and the parasitic (perhaps better called \"evolutionary\") pieces are:

-   Additional Level 3 nodes

-   Updated control system processors.

The \"evolutionary\" pieces will gradually be introduced with minor, if
any perturbations on operation of the experiment. The time scales /
milestones for these are essentially already in the schedule: they get
\"used\" as acquired and commissioned.

The \"parallel\" pieces will need to be adopted at \"cutover\" periods.
This is basically what should be noted in the installation/commissioning
schedule. We can test things I advance, but at some point(s) we have to
:

-   Use the new DAQ hosts for data logging

-   Migrate file systems to the new File Servers

-   Migrate ORACLE databases to the new DB Servers

Each of the above steps is major, but with sufficient preparation can be
done quickly (a couple days at the most, per item).

## Overall Plan

We have a fully resource loaded installation and technical commissioning
plan. A brief excerpt is included below. The full plan is detailed in
Appendix A.

Figure 1: Overview of the RunIIb Installation and Technical
Commissioning Plan.

# Commissioning for Physics Quality data

## Commissioning with Beam

### Silicon Detector

Physics Commissioning (\~4 months total time) consists of the following
steps:

**SDAQ Calibrations**: Perform pedestal calibrations and lists of noisy
and dead channels. This task will begin without beam immediately after
technical commissioning is complete.

Tools: existing SDAQ software modified for the Run IIb detector

Prerequisites: technical commissioning

Time: 2 days for first calibration, 3-4 weeks for physics quality
calibrations

> **Timing-In:** Time-in the entire silicon readout with the rest of the
> detector. This can begin with first beam.

Tools: exisiting offline SMT examine modified for Run IIb detector

Prerequisites: colliding beam

Time: 1 week

> **Tracking Studies:** There are a number of reconstructed track
> studies that must be completed. The first is mapping verification
> which will be done with online efficiency measurements. Other checks
> including track distributions in phi and eta and number of tracks
> attached to reconstructed vertices will be performed with online
> examines and offline reconstruction.
>
> Tools: new tracking algorithms for Run IIb detector, online efficiency
> tool still to be developed, online examines modified for Run IIb
> detector (tracking still needs to be incorporated into SMT examine),
> offline reconstruction

Prerequisites: SDAQ calibrations and timing-in

Time: 2 months

> **Alignment:** The new silicon detector must be aligned with magnet
> off beam data. This task should result in a milestone with the
> production of sensible DCA plots.

Tools: exisiting alignment code (Guennadi Borrisov)

> Prerequisites: SDAQ calibrations, timing-in, tracking studies, \~500k
> events from magnet off data

Time: 1 month

> **Analysis:** Physics commissioning can be declared completed with the
> successful production of plots of physical processes. Appropriate
> milestones would be J/psi and Ks peaks.

Tools: offline reconstruction

Prerequisites: SDAQ calibrations, timing-in, tracking studies, alignment

Time: ?

### Trigger Upgrade

For the trigger systems, physics commissioning generally concentrates on
measuring trigger efficiencies and turn-on curves for objects
(electrons, jets, muons, tracks, etc.) that pass the offline selections.
A major advantage, with respect to Run 2a, for commissioning the Run 2b
trigger systems is that there are essentially no changes to the detector
readout data that feed the Level 3 trigger and the offline
reconstruction (with the notable exception of the silicon data). This
implies that there is already an established method for selecting
unbiased objects to measure trigger efficiencies, and that these to not
have to change between Run 2a and Run 2b. Also, the code that was used
to for physics commissioning of triggers in Run 2a can be reused in Run
2b with relatively small modifications.

**Level 1 Calorimeter**

A major task to prepare for physics quality data is to verify the
functioning of the L1 cal trigger with data, measure efficiencies and
understand the calibration of the L1 Cal trigger. Of course, even before
we calibrate the energy turn on, we can still collect physics quality
data as long as we have verified the functionality of the trigger.

In Run 2a, one of the first comprehensive studies of L1cal turn-on and
efficiencies, D0note 3949, was done with \~5 pb-1 of data. Even now, we
can collect this amount of data in less than a week. The general method
was to use muon triggers to collect events with unbiased electrons and
jets, then to see which of these fired the calorimeter trigger terms as
well. In Run 1, this analysis took about a month after the data were in
hand, but this could go much faster in Run 2b since the offline
definitions of the objects and their energy scales are already known.

Cal Track Match:

Because we already use the Level 1 Central Track Trigger tracks at the
Level 1 Muon Trigger, one of the first commissioning tests we can do are
to compare triggers output from the Level 1 CTT and Level 1 Muon with
those output from the Level 1 Cal-Track Trigger. This would give us
confidence there are no timing problems and the track information is
used correctly.

Using the same idea we can compare triggers output from the Level 1
Calorimeter Trigger with those output from the Level 1 Cal-Track Trigger
to verify we are correctly using the Level 1 Calorimeter information. It
may be that lowering the jet ET thresholds will allow us to use cosmic
rays to verify the actual track - calorimeter matching algorithms
initially with the event display and later with offline analysis.

**Central Track Trigger**

Once the technical commissioning of the new DFEA hardware is complete,
the physics commissioning really consists of checking that the new
algorithms are working properly. This is something that is already
somewhat routinely in Run 2a. For example, when the tolerance on the
beam position is changed, new equations are generated, checked in the
simulator, then loaded online and checked with online examine and
offline analysis. There is little or no downtime associated with these
transitions. The change in equations for the Run 2b algorithm will be
more extreme, but the same method should work for checking their
performance.

The existing \"CTT analyze\" program is run on data regularly to measure
the efficiency of the CTT with respect to tracks found offline. This
program gives meaningful results with only a few runs of data, so we
already have a powerful tool for commissioning the Run 2b CTT.

**L2 Beta Trigger**

The physics commissioning of the L2 Beta trigger consists of
commissioning the algorithms. The addition of new algorithms in Level 2
is regularly occurring process and the procedure is well-established in
Run IIa. New algorithms are tested first in the off-line simulator, both
with Monte Carlo and with real data. The algorithm is then run on-line
in \"shadow mode\", where is is executed and the results recorded, but
it does not contribute to the trigger decision. Once the performance of
an algorithms is verified in shadow mode, it can be added to the
official physics triggers.

The process of commissioning L2 algorithms thus contributes little or no
downtime to the experiment. The algorithms needed for Run IIb can be
commissioned during the first two months of Run IIb, when the
accelerator model indicated that the luminosity will be increasing
gradually.

.

**L2 Silicon Track Trigger**

The final commissioning of the Run IIb STT requires real tracks from the
SMT and from the CTT. This final stage can begin only after the SMT is
installed and running and the accelerator is providing colliding beams.
Based on Run IIa experience, we estimate that two months with beam will
be required before the upgraded STT is fully commissioned for physics.
During this period, all of the rest of the trigger and DAQ can continue
to

operate.

**Online System**

All of the upgraded elements will be installed and tested before first
beam. Physics commissioning consists of installing and testing Level 3
algorithms. As in Run Iia, this is done by the level 3 group and is
continually refined during data taking. Before including tracking
objects into level 3, the new SMT mapping and reconstruction must be
verified. However, the experiment will be taking physics quality data
even before applying level 3 algorithms on fully reconstructed SMT
tracks.

**Offline/Computing**

For the new silicon detector, the major need is the silicon unpacking
code This will be checked during beam using the SMT examine program and
offline using the offline reconstruction program.

**Databases**

**Databases for silicon**

New database tables are needed for the new silicon geometry.

**Databases for trigger**