**Collider Operation**

The purpose of collider operations is to provide collisions of protons
and antiprotons for the experiments. In preparation for collider
operations the Tevatron takes 150 GeV protons and antiprotons and
accelerates them to 980 GeV. During collider operations the Tevatron
maintains the two particle beams while controlling the squeeze points
for collisions. (The low beta quads control the squeeze.) This process
continues as long as the luminosity remains at a useful level. TEVMOD1

**Proton Only**

Physicists use the proton only mode for studies. (In general,
accelerator studies fall into two categories: first and primarily,
they\'re used to increase machine efficiency in creating, transporting,
and accelerating particles so that experimenters can better understand
and make discoveries about the properties of matter; second, they help
physicists understand particle accelerators.) TEVMOD2

**Dry Squeeze**

The purpose of a dry squeeze is to make sure the magnet fields will
remain at consistent levels before loading the next store. To this end,
the Tevatron magnet currents are all briefly ramped to their "collision"
values with no beam in the machine. TEVMOD3

**Ramping**

The Tevatron power supply program repeatedly run through its cycle from
90 GeV to 150 GeV to 980 GeV to 150 GeV and then back to 90 GeV. (When
you ramp a power supply you change its output current from one level to
another. When you change the current you change the strength of the
magnet's field.) TEVMOD4

**Recovery**

The purpose of Tevatron recovery is to reset all systems needed to turn
on and operate the accelerator after a trip. The power supplies
repeatedly ramp up and down in this state. TEVMOD5

**The Tevatron is now off**

When the Tevatron is off there is no beam in the accelerator. (Any beam
left in the accelerator was aborted---intentionally routed to a beam
dump.) TEVMOD6

**Shutdown**

The Debuncher and Accumulator rings are located in the same tunnel and
are part of the Antiproton Source. These rings contain no circulating
beam when shutdown. APSMOD1

**In Access Mode**

When a tunnel is in access mode it has been made ready for people to
enter. The Debuncher and Accumulator rings contain no circulating beam
during an access and beam cannot be sent to the area. APSMOD2

**Stacking Mode**

The Main Injector sends protons to a nickel target in the AP1 transfer
line to create antiprotons. The Debuncher captures the antiprotons
coming off of the target and prepares them for injection into the
Accumulator. The Accumulator collects (stacks) and stores the
antiprotons until needed. APSMOD7

**Shots to the Tevatron**

A shot is the injection of antiprotons from the Accumulator to the Main
Injector and then from the Main Injector to the Tevatron. APSMOD9

**Shots to the Recycler**

A shot is the injection of antiprotons from the Accumulator to the Main
Injector and then from the Main Injector to the Recycler. APSMOD12

**Antiproton Source is NOT ready to transfer**

The setup for the sequence of events that must happen to transfer
particles from the Accumulator to the Main Injector has NOT been
completed. PSHOOT1

**Ready to Transfer**

The setup for the sequence of events that must happen to transfer
particles from the Accumulator to the Main Injector has been completed.
PSHOOT2

**Unstacking Pbars**

The Accumulator manipulates the antiprotons out of the core (the densest
part of the beam), forms separate RF buckets full of antiprotons (a
bucket is a stable region in Longitudinal phase space), and then moves
each bucket to the proper position for transfer into the Main Injector.
PSHOOT3

**Ready for Main Injector Tune up**

The setup for the sequence of events that transfers particles from the
Accumulator to the Main Injector has been completed. The transfer of
antiprotons is waiting on the Main Injector tune up. PSHOOT4

**Pbar Shot Setup is Complete**

The setup for the sequence of events that transfers particles from the
Accumulator to the Main Injector has been completed. PSHOOT5

**Beginning Reverse Proton Tune up**

The Antiproton Source uses protons injected in the opposite direction of
the antiprotons, and since they have an opposite charge they can be used
for tuning and calibration. Protons are cheaper to use than antiprotons.
MSHOOT3

**Reverse Proton Tune up is Complete**

The Antiproton Source has completed its tune up using protons injected
in the opposite direction of the antiprotons. MSHOOT4

**Global Collimator Abort**

All the Tevatron collimators stop moving. TEVCOL1

**User Defined Test State**

This is an arbitrarily defined test state for accelerator studies.
TEVCOL2

**Going to Initial Positions for Halo Removal**

All the Tevatron collimators move quickly to a position 1/2 the distance
to the beam within a prescribed amount of time. This position is
expected to be just outside of the halo. TEVCOL3

**Begin Halo Removal Scraping**

One at a time, each Tevatron collimator moves slowly into the beam halo.
The collimator motion is controlled by loss monitor feedback and
continues until a loss monitor reaches a preset loss value. (This state
follows the "Intermediate halo removal" state.) TEVCOL4

**Retracting Proton Collimators**

All the Tevatron collimators pull out forty mils or 1 millimeter. At
this position they will reduce the halo, but not interfere with the
protons. TEVCOL5

**Scraping During Store**

The Tevatron collimators exclusively remove the proton halo during a
proton only store. (The definition of this state does not match its
intended purpose.) TEVCOL6

**Going to Initial Positions for Proton Removal**

When this state is used, three E0 collimators will move quickly to a
position close to the protons. (The two states TEVCOL7 and TEVCOL8 are
designed to be an integral part of Run IIB Collider. These two steps
will remove protons from the Tevatron and begin the process of recycling
antiprotons from the Tevatron to the Recycler.) TEVCOL7

**Beginning Proton Removal Scraping**

When it is used, three E0 collimators will remove protons from the
Tevatron. (The two states TEVCOL7 and TEVCOL8 are designed to be an
integral part of Run IIB Collider. These two steps will remove protons
from the Tevatron and begin the process of recycling antiprotons from
the Tevatron to the Recycler.) TEVCOL8

**Going to Safe Position**

All the Tevatron collimators move simultaneously to the "safe" position,
which is the farthest out of the beam position. TEVCOL9

**Intermediate Halo Removal**

Sets of Tevatron collimators move in until the beam halo is found by
using loss monitor feedback. Once one collimator discovers the halo the
entire group of collimators stop moving. (This step speeds up the halo
removal process.) TEVCOL10

**Retracting P-bar Collimators**

All the antiproton collimators retract approximately one millimeter (40
mils). TEVCOL11

**Accumulator Lattice Set to Stacking Mode**

The quadrupole power supply currents are ramped to a different level
than that of shots to make for better stacking. APSLAT1

**Accumulator Lattice Set to Shots Mode**

The quadrupole power supply currents are ramped to a different level
than that of stacking to optimize shot emittances. APSLAT2

**Collimators are at Injection Positions**

The collimator injection position is the "safe" position, which is the
farthest open position. TSCRAP1

**Halo Removal in Progress**

The Tevatron collimators have begun moving into the halo. The
collimators follow a specific pattern of TEVCOL# states. TSCRAP2

**Halo Removal is Complete**

The Tevatron collimators are pulled back to the "safe" position (which
is the farthest open position) just before the start of a store. TSCRAP3

**Proton Removal in Progress**

The Tevatron collimators are moved into the proton beam according to a
special pattern of TEVCOL# states. TSCRAP4

**Proton Removal Complete**

The Tevatron collimators are moved out of the proton beam according to a
special pattern of TEVCOL# states. TSCRAP5

**Proton Injection Front Porch**

The Tevatron power supplies first have their currents lowered to 90 GeV
levels, to rid the magnets of any remnant fields, and then raised to 150
GeV for proton injection from the Main Injector. During a proton
injection front porch, the Tevatron is held at its 150 GeV injection
energy to allow the injection tune-up to proceed. CLDRST1

**Proton Injection Tune Up**

The Main Injector sends 150 GeV protons through the P1 transfer line and
into the Tevatron. A program called Injection Closure uses the protons
to make suggested P1 line magnet adjustments to the particles' incoming
angle so that they match with the Tevatron. An operator looks at the
suggestions and chooses to accept them or not. CLDRST2

**Reverse Injection**

The Tevatron sends 150 GeV protons through the A1 transfer line and into
the Main Injector. A program called Injection Closure uses the protons
to make suggested A1 line magnet adjustments to the particles' incoming
angle so that they match with the Main Injector. An operator looks at
the suggestions and chooses to accept them or not. (Protons are used for
this tune up because they are cheaper to use than antiprotons.) CLDRST3

**Inject Protons**

The Main Injector sends one bunch of 150 GeV protons at a time through
the P1 Line to the Tevatron in preparation of a store. CLDRST4

**Pbar Injection Front Porch**

The Tevatron power supplies first have their currents lowered to 90 GeV
levels, to rid the magnets of any remnant fields, and then raised to 150
GeV for antiproton injection from the Main Injector. This state is used
during the rare occasions when antiprotons are the only particles being
injected into the Tevatron. CLDRST5

**Inject Pbars**

The Antiproton Source sends 8 GeV antiprotons from the Accumulator to
the Main Injector. The Main Injector accelerates the antiprotons to 150
GeV and then sends them four bunches at a time through the A1 line to
the Tevatron in preparation of a store. CLDRST6

**Cogging**

This state is not used. (The term refers to the process of spacing the
protons and antiprotons properly so they collide at the correct places
around the Tevatron.) CLDRST7

**Preparing to Ramp**

This state presets power supply ramp values before the protons and
antiprotons get accelerated to their next energy level. CLDRST8

**Acceleration**

The Tevatron accelerates the particles to the flattop energy of 980 GeV.
CLDRST9

**Flat Top**

The power supply currents are held at their 980 GeV level. CLDRST10

**Squeeze**

The low beta quadrupole magnet fields tightly focus the proton and
antiproton beams at the interaction points around the Tevatron ring.
CLDRST11

**Initiate Collisions**

The electrostatic separators near each interaction point change their
voltages. This causes the spiral orbits of the proton and antiproton
(which normally are keep away from each other) to come together within
the detectors and produce collisions. CLDRST12

**Remove Halo**

Tevatron collimators remove the proton and antiproton halo per the
TEVCOL# states control process. CLDRST13

**High Energy Physics**

Shot data is saved for later analysis. As soon as this is completed,
operators inform the experiments that the store is ready. CLDRST14

**Pause High Energy Physics**

During a pause, Tevatron experts may conduct studies or Operations may
scrape the beam. CLDRST15

**Proton Removal**

This state is for Recycler operations. The Tevatron will use this state
to remove protons before injecting (recycling) the remaining antiprotons
back into the Recycler. CLDRST16

**Unsqueeze**

The low beta quadrupole currents and separator voltages return to their
normal 980 GeV values in preparation for ramping down and beginning the
next shot setup. CLDRST17

**Secondary Flat Top**

The secondary flattop refers to the portion of the 980 GeV ramp that
occurs after the "Unsqueeze." CLDRST18

**Deceleration**

This state is for Recycler operations. The Tevatron RF system reduces
the antiprotons' energy from 980 GeV to 150 GeV. CLDRST19

**Extraction Porch**

The power supplies have ramped down to 150 GeV current levels. This is
also called the "Back Porch." CLDRST20

**Extract Pbars**

This state is for Recycler operations. The Tevatron will recycle
antiprotons to the Recycler. CLDRST21

**Reset**

The Tevatron power supplies have their currents lowered to 90 GeV levels
to rid the magnets of any remnant fields. This is sometimes referred to
as the "dip." CLDRST22

**Recovery**

When the Tevatron trips off due to a problem, such as a quench, the
power supply current is bypassed, or "dumped," but the supply's ramp
command gets held at whatever GeV level the collider state was asking
for. It's necessary to free the ramp before turning the power supplies
back on. To do this the supercycle is allowed to play out, that is the
ramp commands continually run through all the ramps from 90 GeV to 150
GeV to 980 GeV to 150 GeV and back to 90 GeV. CLDRST23

**Ramping**

The power supplies' current levels repeatedly play out their ramps from
90 GeV to 150 GeV to 980 GeV to 150 GeV and back to 90 GeV. CLDRST24