We continue to run well.|
ZDC rates for 62.4 GeV/n since last Monday.
The 62.4 GeV/n run is progressing along very well.|
ZDC rates for 62.4 GeV/n since last Monday.
We had 3 instances, since starting the 62.4 GeV/n run, where
the STAR magnet tripped off, followed by a spike up (as much as
over 5 orders of magnitude) in the vacuum at STAR.
This is caused by electron cloud in the STAR IR, normally suppressed
by the presence of the solenoidal field.
In the past a trip of the STAR magnet did not cause such a large increase
in the vacuum, but at the lower energy we are running slightly more intense
beams, and past magnet trips (during the 200 GeV/n run) occured at times
when the beam was not so intense. To prevent this from occurring we have
put the STAR magnet into the permit system. If the magnet trips again the
beam will be aborted, preventing the buildup of an electron cloud at STAR.
STAR vacuum showing 3 spikes when the Solenoid tripped off.
STAR background rates showing effect of vacuum on STAR.
Since Saturday evening, we have been running very well.|
ZDC rates for 62.4 GeV/n since Saturday evening.
The 62.4 GeV/n run is to a good start. Machine setup went|
well, running with 111x111 bunches and 1.3e9 ions/bunch from the
very first set of physics stores. There was a power dip yesterday
that kept physics off for about 12 hours. Otherwise we are running
ZDC rates for 62.4 GeV/n since Friday.
62.4 GeV/n Au+Au run started physics late this afternoon.|
ZDC rates for 62.4 GeV/n.
200 GeV/n Au+Au run ended this morning at 8 am.|
We began setup for the 62.4 GeV/n Au+Au run this morning.
ZDC rates for March.
ZDC rates for February.
ZDC rates for January.
Except or an interruption in physics due to a |
strong storm that came through hardest on
Saturday, we have had steady running.
On Saturday we shut down for most of the afternoon, for
about 9 hours, since there were multiple power dips occuring.
ZDC rates since Thursday morning.
Yesterday was a maintenance day.|
We came out of maintenance and started running physics
by 7:30pm (last night). This can be credited to the diligence
and hard work of the maintenance and operations teams.
At the beginning of the week we ran into a problem in which
Yellow beam decays increased significantly.
It was found that the transverse coupling had changed.
On Monday we went into a development period where we looked at
improving the rebucketing, fixing an injection synchronization
problem, and building a new tune/coupling replay file, by
performing an tune/coupling feedback ramp. Things were improved
in some ways, but we still were not running as well as the
week before. On Tuesday we reverted some of the changes made
on Monday, and tuned up the store working point in yellow.
ZDC rates since last Sunday.
We have been running well the past week (as |
evident from a lack of much to say in this chronology lately.)
For the most part, what we have been focusing on this past week
is improving rebucketing and maximizing rates in the PHENIX
30 cm vertex window.
Our best stores of the run have occurred in the past 10 days.
ZDC rates since last Wednesday.
This has been a busy and productive week, since my last|
entry. Here is how things looked:
ZDC rates since last Wednesday.
The past couple days have seen very good|
running. We have fit in 8 stores with high rates.
The instabilities at transition are under control,
after raising the chromaticities in Yellow around
There has been good progress in the stochastic cooling setup
for both rings. The last physics store had both Yellow
and Blue longitudinal cooling on for the entire store.
Last night was APEX and this morning we went into maintenance.
We come on with physics again this evening.
We ran well this weekend, fitting in 12 stores|
ZDC rates since Friday.
One issue we are working on is instabilities now appearing
after transition. So we have been working on increasing octupole
strengths at transition and trying different intensities, which
helps understand the source of the instabilities.
This has been a difficult week. Beam conditions |
have not been good. The main problem was we had high losses.
on the ramp. This is best seen the following graph, showing
our ramp efficiency vs fill number. Over the week this
efficiency was dropping and bunch lengths were suffering.
The first fill number after the maintenance was 11697.
Ramp Efficiency since Friday, Feb. 12.
The source of this problem turned out to be a bug in
the LLRF, causing the transition phase jump timing to shift
slightly every ramp.
ZDC rates since Friday.
We had a maintenance day on Friday and by Saturday|
afternoon we were running again, although at reduced
intensities while vacuum in RHIC recovered.
There were two areas where we opened up the vacuum to air
to do work on the maintenance day. Both were to repair
stochastic cooling equipment. The Yellow longitudinal
kickers, now repaired, were reinstalled and the Blue vertical
pickup was repaired. The vacuum in these areas is still
recovering, limiting the beam intensity.
The good news is the repair of the Blue vertical pickup has
improved the transverse cooling in Blue, so that the cooling
rate in Blue now is equal to the rate in Yellow.
ZDC rates since Friday morning.
This has been a tough past few days. |
ZDC rates since Tuesday morning.
Tuesday morning we went off for an hour to allow PHENIX an
access to make a repair to their EM calorimeter.
The following store was lost to a QLI, which was caused by
yi10-dh0 having a sudden change in its reference. The
regulator card on that supply had to be changed. The next
store was also lost due to a QLI. This time it appears there
was a timing problem in the 11b-qd1 front end computer. The
computer was reset, clearing the problem.
Tuesday night into Wednesday morning we ran well. Wednesday
morning a store was cut short by a QLI that occured at 5:55am.
At the same time an ODH alarm came in, which kept us off for the
rest of the morning. An ODH sensor had to be replaced.
Of course, on Wednesday Long Island was hit with a major winter
storm. As the day progressed working to get the accelerators
running was naturally hampered by poor weather conditions.
In the afternoon an attempt was made to put up a store, which
failed when another QLI came in, from the yellow quadrupole
flattop module (from yo9-qd7). The problem was due to an
airflow fault. This finally cleared by 3pm. During this time
the AGS main magnet power supply tripped off. This also had
an airflow problem (bad sensor). The AGS main magnet was on
again by 4:40pm. By 5:16pm a store was up with physics running,
but this didn't last long, tripping off again on the yellow
quadrupole flattop module air flow fault at 5:21pm. Again, due
to the weather, a temporary measure was taken in which the
airflow interlocks were bypassed (by the system engineer). This
didn't cause any protection to be lost, since there are redundant
temperature interlock systems on these power supplies. In the
process of recovering another QLI, this time from yo4-qd3 which
had gone into oscillations. This required a repair of a contactor.
By 9:43pm we had another store up, running physics. This store ran
until 10:56pm, at which time a vacuum interlock from sector 4
caused the beam to be dumped. The vacuum spiked up in the area of
the Blue stochastic cooling longitudinal kicker. In a short amount
of time it pumped down again enough for us to operate.
Just before midnight we got up another store, which lasted almost a
full four hours, but was lost due to another QLI (yo5-qf2-ps had
tripped to the Off state). After recovering a successful store
was put up that lasted the full four hours. The next store had
rebucketing problems and had to be aborted. That was followed by
another successful store that lasted until the start of APEX.
Thursday night starting at 7pm was for APEX. There were many
problems during the APEX, causing much lost time.
Starting at 7am Friday we went into a scheduled maintenence.
We ran well over the past day. Yesterday during|
the day we were off for 1 1/2 hours when the abort
kickers prefired (at the beginning of a store). It
took time to recover since this caused a real quench.
At 1pm the beam was interlocked by a faulty beam loss
We are now running routinely with Blue longitudinal,
Blue transverse, and Yellow transverse stochastic cooling.
Cooling is not quite as effective as it could be due to
a problem with the Blue transverse pick-up.
Blue with longitudinal cooling.
Yellow with no longitudinal cooling.
We ran all weekend, although it was not completely|
smooth and efficient running. The time between stores
averaged over 1.5 hours. Sunday day was a difficult day,
in which we were struggling with instablities at
transition. There were also some human errors made.
Some incorrect transition timing settings were put in
for a couple of the ramp attempts.
We ran with both Yellow and Blue transverse stochastic
cooling this weekend. Yellow is performing very well, while
Blue does cool, it is not as effective due to a known problem
with the pick-up. This is planned to be repaired on this
As part of the ramp development done for the STAR magnet
polarity reversal, we moved the Yellow working point (betatron
tune settings) to a location that recent simulations suggested
would have more momentum aperture. This has proved to be
a good change, since we have been able to increase the
voltages on the 200 MHz cavities over the weekend, improving
the rebucketing for both Blue and Yellow.
Yesterday we developed a new ramp with the STAR |
magnet polarity reversed. The time to reverse the polarity
(which involved mechanical work in the power supply) was
a little over 4 hours. To develop the new ramp took 3
RHIC ramps - one with tune feedback, one to do feedforward,
and a third to fine tune things with slightly higher intensity.
Physics was on again by 8:30pm (off a total of 12.5 hours).
We ran 3 stores overnight.
We have run 6 stores since Sunday evening.|
Early Monday morning we were held off due to a problem
with the yi10-q89 power supply. After that fault cleared
we got up a store that was quickly lost due to an abort
kicker prefire. It took a few hours to recover from this
fault. During the day Monday we shut down to allow experimental
access. In coming on after the access we had a QLI. It took
a few hours to recover from this fault. Yesterday we were
off for almost five hours. A store put up at 11 am was lost
to a QLI. This was due to a fault in the bi5-qf3 power supply.
This morning problems with the same power supply made
operation difficult. The power supply is being replaced.
Today is APEX, once bi5-qf3 power supply is replaced.
Physics ran all weekend.|
Stores for the weekend.
Physics ran all day.|
Even with the larger beta-star, we are momentum
aperture limited in Yellow. So while we are able to
bring on rebucketing, we cannot run at full voltage.
The last 6 or 7 stores we have explored the level
of voltages we can operate with.
Polarized proton studies in the AGS continue to run behind
Yesterday was a long maintenance day.|
Physics was on again this morning at 2:40am.
During the maintenance day the Yellow longitudinal stochastic
cooling kickers were removed. They will be repaired in the lab
and re-installed in a later maintenance period. The Blue transverse
kickers were inspected and checked for leaks, but were not removed.
They can still be used for cooling.
Other major work was done at PHENIX. They took over 12 hours to
make repairs to different parts of the detector.
The AGS also took a long day to re-install the J7 stripping foil,
used to dump the gold beams more efficiently, and to work on the
polarimeter. Polarized proton development has begun, working
behind RHIC stores.
Physics ran all day.|
We began ramping up the rebucketing voltage today.
As of this morning we are up to 3.3MV, working towards
a total of 4.9MV. High high we can go may be determined by
how much momentum aperture we find we have for this lattice.
Studies during tonights APEX will measure this.
APEX begins tonight at 7pm. Tomorrow is Maintenance.
Physics running this weekend was cut short|
when a vacuum failure occurred on the blue transverse stochastic
cooling kickers located in the 12 O'Clock warm section. Water
got into the vacuum compounding the problem and causing it to
take longer to pump down, once the leak was isolated.
Beam went off with a QLI triggered by beam losses in Blue
at 10:24am Sunday morning. Physics was on again at 7:27am this
On Friday at 4:41pm we finally got physics running on the new
lattice with the beta-star at 0.7m (previously it was 0.6m)
This enabled us to bring on rebucketing without large beam
losses. Over the weekend we ramped up with beam intensity
to be running at 1.3e9 ions/bunch with 111x111 bunches by
Yellow transverse stochastic cooling became operational on
Friday evening. It has been on for every store this weekend,
so we are gaining experience with using it.
We have learned that without Blue transverse cooling the
yellow beam becomes much smaller than the blue beam, causing
luminosity to suffer later in the store. Today we will begin
reducing the amount of Yellow cooling after 1 hour into the
store and try to optimize the luminosity.
Yesterday we spent putting up a new ramp with|
a larger beta-star. After looking over data from
the various APEX and machine development studies
over the past week or so, it was concluded that
with a beta-star if 0.6m we simply didn't have
enough momentum aperture to turn on rebucketing.
A number of things were tried to increase the
momentum aperture, but with limited success. So
yesterday we put together a new ramp with a beta-star
of 0.7m (successfully used for the dAu run) and
overnight we worked on tuning it up.
This morning we have put up an 84x84 bunch store with
1e9 ions/bunch with rebucketing on (only without the
common cavities). During the day we will work on
putting up a 111x111 bunch store with rebucketing on
(with common cavities? - to be discussed). This should
put us into a good state for running physics this weekend.
Yesterday was APEX, with a focus on the problems|
associated with rebucketing. Although we gained
new insights into the problem, we did not come up
with anything that would allow rebucketing to be brought
on with the given optics. So it was decided later
in the afternoon that we will develop a new ramp
in which we go to a beta-star of 0.7m instead of 0.6m.
The basic idea is the smaller beta-star causes the
momentum aperture to be reduced to a level that when
we bring on the rebucketing cavities, which causes
the momentum spread to increase, we no longer fit
within the existing momentum aperture.
This work will begin this afternoon.
In the evening we put up one store that had
Yellow stochastic cooling (transverse) on.
Here is how it compared to previous stores:
PHENIX normalized coincidence rates for 4 different stores.
The brown curve for store 11505 is with cooling turned on.
Overnight we ran 2 more stores for physics.
Here is how we ran for the last 24 hours.
Stores for the last day.|
The store yesterday afternoon was longer in
order to allow an access into the AGS. This
was to check the AGS cold snake.
At the end of that store, venier scans were
done for both STAR and PHENIX.
Early in the evening, LLRF looked at beam
at injection to debug a problem with kicker
timing shifts during injection. This caused
some bunches to lose intensity during fills.
Today, from 8am to 8pm is APEX.
The weekend went very well, with a total of 16 |
four hour stores for physics.
A few hours early Sunday morning were lost due,
initially, to an abort kicker prefire. Then there
were problems yo1-th8, which had to be replaced.
Here is how the week looked: Stores since Tuesday, Jan. 12
Since Friday night, we have been just putting|
up stores for physics. As of 3:30 Sunday,
we have gotten up 9 good (4 hr) stores for physics.
When marching along, the time between stores (collisions on
to collisions off) is 30 to 40 minutes.
This is as fast as possible given times to ramp
down, fill, and ramp up again.
Here is how it looks: Stores since Friday
Last night, at 7 pm, Store 11462, the stochastic |
cooling team succeeded in getting
transverse cooling working in Yellow. Since the lattice was well
coupled, they were able to cool both horizontal and vertical
planes using just the vertical cooling system.
Here is seen the cooling in action, starting at 19:00: Cooling in store 11462
We did not recover from Wednesday's maintenance until later yesterday
afternoon. What held us off from running again was a very
subtle problem introduced into the LLRF during the maintenance.
Last night and today a number of tests were
performed in order to understand better the problem
with rebucketing in Yellow. We continue to run
without rebucketing because of a large beam loss
that occurs during rebucketing in yellow.
We will continue to work on getting rebucketing
working next week.
Yesterday was a maintenance day.|
Physics has not yet resumed, as of 8 am this morning.
The maintenance was extended due to a problem with the
Booster F6 extraction septum magnet. The magnet developed a short.
This was worked on in the evening and we were able to clear it.
The vacuum leak at the yellow longitudinal stochastic cooling
kickers turned out to be worse than originally thought. There
are three kickers in this unit, each individually cooled, but on
a common system. The leaks are in the cooling lines to RHIC vacuum.
All three kickers are leaking, suggesting a common failure mode.
For now we are keeping the cooling lines under vacuum, preventing
the kickers from operating.
Another big job worked on yesterday was the J7 plunging stripping
foil in the AGS. This is used to strip the two extra electrons from
the Au+77 beam before being dumped into the AGS J10 dump. Although
not required for operation, since we can dump the Au+77 beam cleanly
without it, it does allow beam to be more effectively dumped.
The mechanism had failed on Dec. 28, jamming in an almost inserted
position. This did affect the beam intensity in the AGS, since we
had to bump around it, so with it now removed we may be able to push
intensity slightly higher (but only by 10% or so).
As an aside, preparations are under way to begin polarized proton
development in the AGS, behind RHIC stores. This work is development
for the next RHIC polarized proton run (FY11?).
This beam development will begin next week.
We ran two stores for physics yesterday morning.|
An attempt to put in a third store at noon failed
due to a LLRF problem. The afternoon was spent diagnosing
this problem. Later in the afternoon there was a vacuum
PLC that failed, preventing beam from being injected.
The PLC didn't get repaired soon enough to get another store
up before the start of APEX, originally scheduled to start
at 8 pm. As a result of these failures APEX began at 7:14 pm.
APEX ran all night, ending at 8 am. Today is Maintenance.
We ran physics for the entire period yesterday to this|
morning. A few hours were lost due to a lead
flow problem. In the evening a few stores were
not successful. Two of them were lost due to beam
losses at transition with high bunch intensities.
The third was lost when beam debunched at injection.
The basic problem causing the sextupoles to trip off was|
fixed last night. A couple short stores got put up
earlier this morning, but they were dumped by
a fault in Yellow 2 O'Clock TQ6.
We are now running with 111x111 bunches with
1.1e9 ions/bunch. But we are still running with
the storage cavities off (no rebucketing).
Our focus will now move to understanding why
turning on rebucketing causes so much beam loss
and working on commissioning stochastic cooling.
The weekend has not been very good for integrating luminosity.|
Yesterday we were off most of the day due to
a vacuum problem at the stochastic cooling kicker
at 11 O'Clock. A store was put up at around 00:45
this morning and another at 6:30. This store was
lost when a sextupole tripped off. Today there has been
a number of problems, although sextupoles tripping
QLI's has been the most significant.
The past day was another difficult struggle to get beam|
lifetimes under better control.
Yesterday morning was given over for experimental
access. Problems with the accesses forced a sweep
of the experimental areas and there occured a
problem with a switch in the access controls.
So the 2 hour access stretched out to over 4
hours without any beam activity.
Before beam work could begin, a problem with the
RHIC BPM system was enountered. This took another
hour to sort out. Beam was not injected and ramped
until after 4pm.
The evening was spent working on commissioning
a new ramp, which had modifications in it to improve
beam lifetime at store (otherwise the ramp was no
different than for physics stores). This work continued
until early this morning. There remain some issues
related to this work, most significantly rebucketing
was left off for the most recent store.
We are currently focused on improving store lifetimes, which |
are now limiting luminosity. The store put in early
this morning was 84x84 with 1.1e9, but had lower ZDC
rates than the previous physics store that had fewer
bunches and lower intensity/bunch. This was all due
to poor lifetimes.
Overnight was for APEX. Four areas were studied: IR optics,
orbit response matrix measurements, orbit at PHENIX,
and IR corrections. These all went very well.
Yesterday afternoon we were off due to two failures:
sextupole tripped off (took time to recover) and
the injection kickers started firing while ramping.
The second problem was caused by a configuration error.
Yesterday we went into an intensive 11 hour development period.|
This was admittedly not well planned out, but
it proved to be highly productive. The main original
goal of this development was to measure the chromaticity
(first and second order) and dynamic aperture with a
6x6 bunch ramp. What was found was chromaticities (first
order) were far from where they should have been in a
number of places. In particular the vertical chromaticity
at Yellow store was large and negative, while it should
be small and positive. So we chose to correct these
In addition, the LLRF group was ready to put in some
fixes to problems encountered during commissioning.
A major problem has been in the injection cogging.
We have not been able to inject more than one bunch
per AGS cycle. This leaves beam at injection for too
long, causing significant debunching from IBS. They
were able to fix this partially, so we can now inject
3 out of the 4 bunches in the AGS in one cycle.
Finally, work was done to improve the rebucketing,
which is now working much better and with higher voltages.
We changed the store lengths to be 4 hours starting last
night. Previously we had set them to 6 hours, to give more
setup time to the experiments. Now we want to ramp up
intensity as fast as possible. Each new store will be
incrementally higher intensity than the previous one.
We continue to work on increasing intensity and run.|
Yesterday an access was made for Stochastic cooling
to work on improving the signals from their pickups.
We also worked on improving the rebucketing, adding
two common cavities to achieve higher voltage.
We lost one store last night due to a problem in the
LLRF, causing a significant amount of beam to debunch.
The last store put up was with 68x68 bunches with
We have started progressively raising intensity each store.|
The most recent store (11365, 1/4/10 at 6:14am) was
with 68x68 bunches with 0.9e9 ions/bunch.
Here is how the weekend stacked up. ZDC's and Intensity over the weekend.
The beam loss that was preventing our going to higher |
intensity was cured today. Over the next few days
we will progressively push the intensity up.
Problems encountered today were system level problems.
Early in the morning there was problem with injecting
beam, associated with the bunch suppression configuration.
Later in the morning there was a quench link interlock.
This was followed by an independent controls problem with
a power supply FEC. After clearing these problems a new
fill was put up at 3 pm. This fill was with modest
intensity, but with corrections put in late in the ramp
cycle, the losses that were holding us from going to high
intensity had dropped significantly.
Overnight we ran with two modest stores. Each was with 56x56|
bunches with about 0.85e9 ions/bunch.
Today, as we tried to raise intensity, either
by increasing the bunch intensity or the number
of bunches, we are inhibited by losses in the
STAR triplets during the beta-squeeze.
Efforts are now going into reducing losses
and raising intensity.
Last night a 56x56 store with 1e9 ions/bunch was put up,|
with rebucketing working.
We are now in a mode where we will be putting up
stores for physics, as much as possible. At the
same time we will be increasing intensity and
the number of bunches.
During the days next week we will be working on
stochastic cooling commissioning.
Most of the day was spent working on commissioning the|
new LLRF for the storage system (200 MHz) RF cavities.
The cavities were phased in and HL control setup, but
the final step of getting beam rebucketed from the
28 MHz RF into the 200 MHz RF needs to be done today.
Venier scans were performed at both STAR and PHENIX
yesterday. ZDC cross section's were measured to be the
same as run Run7.
At 1:30 am we got a 56x56 bunch store up with ~0.6e9
ions/bunch, for experiment setup.
Some progress was made in the last day, although a number of|
failures slowed us down. Yesterday morning we were
kept off due to a bad UPS on the QPS in 1010A. After
that was fixed we were kept off due to lead flow interlocks.
Late in the afternoon we were able to run again and tested
ramping with higher intensity (0.9 to 1.1e9 ions/bunch).
Three such ramps were attempted before a LLRF problem
kept us off for the rest of the evening.
At 4 am, this morning, we got a 56x56 bunch store up
with ~0.7e9 ions/bunch, for experiment setup.
Yesterday was spent on experiment setup using a 56x56 bunch store|
and a first look at stochastic cooling commissioning.
In the evening work continued on LLRF commissioning
and beam development (increasing intensity).
This morning a 61x61 bunch store was established
for experiment setup.
Last night we put in our first 56x56 bunch store, for experiments|
to begin setup for physics. Unfortunately is was aborted by
an abort kicker prefire. Experiments have seen beam to begin
setup, though, over the weekend.
Over the weekend progress was made in the new LLRF setup.
Ring to Ring synchronization was commissioned as well as
store cogging and timing. Both rings have Landau cavities on.
Still to be done is to setup rebucketing in the storage cavities.
We are now ramping up to physics, focusing on store development.
Work continued over the holiday to improve efficiencies on|
the ramp and at store.
Yesterday, for the first time in Run 10, beams were put
into collisions at both STAR and PHENIX (Merry Christmas!).
Before we can work on physics stores, the LLRF needs to
get ring to ring synchronization and store cogging working.
That is being worked on today.
Tuning up of the ramp efficiencies continued today.|
Overnight we have brought beam to store energies in both rings.
Ramp efficieny in Blue is close to 100%, Yellow efficiency is poor.
Transition crossings were worked on yesterday and fixed in both
rings. LLRF attempted to get the Ring to Ring synchronization
working. This needs more work, so we have no collisions yet.
Currently we are focusing on Yellow ramp efficiency.
Ramp development in both Blue and Yellow continued.|
With the focus on tuning up the transition crossing.
With both rings running synchronously, Blue beam
gets to store, although with only about 75% ramp
efficiency. Most beam loss is just after transition.
For Yellow, most of the beam is lost at transition.
Today more work needs to be done with LLRF and ramp efficiency.
Development of beam in Yellow has begun. LLRF setup|
was completed around 2 am this morning.
Currently Yellow is being tuned to get beam to store.
Blue has developed a problem, since we started
ramping the two rings together. Now beam dies
before getting to store. Since the problem is
associated with ramping together, we are investigating
possible causes under that condition.
Newsday reported 26.3 inches of snow - at BNL - when all was said and done.|
Beam development got going last night.
Yellow is now available for ramp development.
Blue didn't reproduce after coming on again,
so effort is going into working on both Blue and Yellow today.
Schedule-wise, we are now a few days behind,
but still pushing to have collisions by Tues. or Wed., this week.
Early this morning the Blizzard of '09 finally shut us down.|
According to the National Weather Service, BNL measured a record
24.9 inches of snowfall as of 7 am this morning.
Beam development in RHIC continued until 3 am, when a cooling
tower for the Booster RF went down, shutting down the Booster.
The rest of today was spent getting roads cleared so we
could re-start operations.
Blue is in good shape, with beam accelerated up to store.
Work began last night on increasing intensity in Blue.
Today Yellow became available, so beam development will
begin tonight in Yellow.
Blue ramp development continued overnight.|
A problem was encountered the night before, in which
the set tunes needed to be near the integer, causing
the on-line model to crash. The actual tunes of (31.23, 31.216)
were achieved by setting the tunes down near 31.05. It is still
being investigated why the model is not getting them right, but
a strong likelihood is new transfer functions that were loaded
into the database over the summer shutdown (to match magnetic
measurements). We reverted back to the old database yesterday
and developed a new ramp, with all the same features. Overnight
this ramp was developed and by this morning beam in Blue is
up to store with >90% ramp efficiency.
Yellow remains off due to a problem with the Q7 Quench Protection
Blue ramp development continued overnight, after being off all day|
for AGS Motor Generator repairs.
The Blue ramp efficiency is improving, up to about 90%.
Last night the PS group ran Yellow up to Store current levels.
Today they need to test on the normal ramp for physics.
Beam in Blue was accelerated to Store last night.|
PS group continued work on Yellow MMPS ramp development.
Ramp development in Blue was expedited by using
tune and coupling feedback for every ramp attempt and
through the use of orbit feedback, which allowed correcting
the orbit through transition in one ramp cycle.
With a smaller beta-star, it is more difficult to correct
the orbit during the beta-squeeze, so these systems helped
speed up the process significantly.
Michiko Minty put together a nice summary of the 1st 24 ramps in Blue.
Blue ramp development summary.
Ramp development for Blue began last night.|
Acceleration and the transition phase jump work well.
LLRF setup for Blue is mostly complete, although they
are still working on cogging.
Yellow MMPS setup progressed today.
Both Blue and Yellow are now setup at injection with RF capture.|
The MMPS for Blue is almost ready for ramp development.
Yellow MMPS will be setup today for ramping.
Tonight we expect to start ramp development with exp. magnets on.
This afternoon we finally got beam circulating in Yellow.|
The problem turned out to be a quadrupole in the wrong polarity.
Now we have begun to work on LLRF commissioning in Yellow.
Also, last night, the MMPS group made progress in Blue, and
we can now use Au101 again. We will begin working on ramp
development in Blue tomorrow morning.
Last night beam was injected into Yellow for the first time.|
Once synchro was set and the kickers timed in it became
clear there was an obstruction in the area of 12 O'Clock.
At most 3 turns of beam would survive.
Today it was found the stochastic cooling pick-up at 12 O'Clock
was not retracted. It would appear it was obstructing the beam.
This evening, beam will be injected again and apertures around
12 O'Clock and the Yellow cold snakes will be probed.
LLRF commissioning for Yellow will be worked on tonight.
For Blue, the PS group is still working on getting the Ramp
to work. We have switched to using the Au100 ramp (which has
the transition jumps at the same time for both rings) as oppposed
to the Au101 ramp (which had them at different times).
A distortion in the lattice around transition, to enable Blue
and Yellow to jump transition at different times, was causing
difficulties in tuning up the MMPS for that ramp. The Au100
ramp doesn't have those distortions.
So far they have almost gotten the current up to store levels, but
more tuning is required.
Work on Blue and Yellow MMPS continues.|
A PS failure yesterday took most of the day to fix
(1st spare didn't work).
Yellow could not run because of a problem in the Yellow valve box.
This will be repaired today.
One attempt to accelerate was made over night, but the ramp failed.
Some beam was accelerated, though, so it was a useful first ramp.
Blue injection is in good shape. Instrumentation is working well.
All other systems are ready for ramp development.
Worked on preparing Blue MMPS to ramp to store.|
Almost ready. Will finish today.
LLRF Commissioning is coming along well.
Not much beam development yesterday, but good thinking time
(when not sleeping), so some improvements were still made
(especially in "understanding").
Some beam work was done last night, at injection.
Blue injection optics are better understood.
Instrumentation is in good shape and ready for ramps.
DX training is finished. It took 3 quenches to get to Brho=840 Tm.|
LLRF Commissioning is coming along well.
They worked all last night and are ready to work on acceleration.
Injection and capture in blue is well tuned up.
Orbits are in good shape and tunes and decoupling are set properly.
Today we prepare the Blue MMPS for ramping.
This evening we begin working on the ramp.
Last night went very well. RF Capture was setup in Blue.|
So LLRF Commissioning is coming along well.
Other work done included instrumentation setup.
The orbit system is working, as well as the base band tune
measurement system, beam transfer function measurements, and
Tonight we hope to do the first ramp in Blue.
Blue injection and circulating beam was established last night.|
DX training was started, continues tonight.
An attempt to inject beam was made, but problems with the AGS L10 cavity|
and with setup of the new RHIC LLRF prevented it.
DX training today and tonight.
We attempt to work on injection again in the early morning hours.
No beam was injected last night.|
Beam sweeps and p.s. checkout took longer than expected.
Tongight we work on injection and possibly RF capture.
As of 6 pm, we remain on schedule. |
RHIC has been swept and secured.
We expect to inject into Blue later tonight.
Both Blue and Yellow at 4.5 K. |
X4 Storage RF cavity Damper was repaired.
"mini-maintenance" this morning. |
Last night beam was re-established to the W-Dump.
Blue is at 4.5 K, starting cooldown of Yellow.
|Dec. 2||RHIC Cooldown remains on schedule. All of Blue is below 10 K.|
On Monday power for the Booster was shutdown (emergency work).|
A side affect was the D3 vacuum valve wouldn't open afterwards.
(valves were closed as a normal precaution).
It had to be opened manually.
As of this morning, beam has not been restored
due to other equipment failures in the Booster.
Beam setup in AGS and to AtR dump is in good shape.|
Today cooldown to 4.5 K begins in Blue. 1st 9 am meeting.
|Nov. 30||Put together plan for next week or so; see Plan from Dec.1 to Dec.8|
|Nov. 24||Working on merge setup in AGS.|
|Nov. 22||Beam has been extracted from the AGS to the W-dump.|
|Nov. 19||Today is an important day, LLRF begins switchover to the new system!|
|Nov. 19||Looks like the last day of the Dry Run. Most tasks are completed.|
|Nov. 16||completed first day of Dry Run. Cryo on schedule.|