start when you want
okay
so good afternoon. Thank you for allowing me to make this presentation. I will
present the Atlas upgrade for next years.
Can I
okay, I need to change the slides. So let's go on slide two. Let's start with
the LHC and High luminosity LHC plans. At the moment we are in long shutdown two there
are some changes on LHC essentially regarding the magnets and the injection
system and we will have also some upgrades in ATLAS as well that will discuss Run three
is also known as ATLAS phase one. Another long shutdown will be after run three that
will bring us in the so called high luminosity LHC era that will see more
improvements on injectors more protons per bunch better focusing, and an instantaneous
luminosity up to 7.5 times 10 to the 34. We expect to collect around 3,000 inverse
femtobarns of data. And of course, there will be some ATLAS upgrades as well. In this case,
this upgrade um this phase is called phase two.
So let's move on slide three.
Let's see what is what is the impact of luminosity on the experiment essentially, for
phase two, the requirements are that all the parts of the experiment have to stand
at the peak luminosity of 7.5 times 10 to the 34, and to keep good performances
at least at least as good as a run two and run three. This means to keep an
acceptable trigger rate to keep low PT thresholds and also to mitigate the pile-up.
We expect an average pile-up of 200 collisions per bunch. Which means
larger event sizes higher trigger rates, higher detector occupancy readout
limitation and reconstruction complexity. But also the detector has to stand with
high radiation levels, which means increased radiation damage and increased activation
of materials. Let me now show a very short summary on the main physical motivation
for the upgrades. This is not representative of the entire Atlas physics
program for the next year for the next phases. There are a lot of presentations
on the Atlas physics program on the upgrades in this conference, I just noted
some here and here. Essentially, I want to mention just that there'll be many studies
on the precision measurements and rare decay searches on the Higgs boson. And also on
the Standard Model processes the study of rare decays like the search for the Higgs in two
muons, and also the search beyond Standard Model that may be concentrated for
example on exotics and susy programs and also dark sectors. Let's move on slide five.
And so, we start talking about ATLAS phase one upgrades these are the upgrades
that I will discuss and this is also the these are also the locations in the
detector. Let's move with the new small wheel detector on slide six. The new small wheel
is a made of two five meter radius wheels in the Endcap region covering the
region of eta between 1.3 and 2.7. Each wheel is formed by two external small thin gap
chambers TGC wedges that are used mainly for trigger for bunch crossing
identification and for vector tracking. And internally they have two micro megas
wedges, which are used mainly for tracking with a spatial resolution less
than 100 microns. On the right top you see the layout of the two wheels uh the
For the large and small sectors, the chambers are built in Institutes in four different
continents. This gives you an idea of the huge effort that the experiment has put in
this project. And which is the aim of the new small wheel, the aim is to reduce the
fake muon triggers in the Endcap region by making a coincidence between the existing
detector, which is the big wheel. And the new small wheel. You can see it here in this
plot in the right middle, where you see some tracks and some particles that are that can be
rejected by using the new small wheel system. Essentially, if you have these three
tracks, you can trigger only on the A track while you can take out the
tracks like B which produces only hits in the in the big wheel. And also tracks like
the C where you have hits in the big wheel and new small wheel but with the, with
the track, it's not pointing in the to the interaction point towards the interaction
point. So maybe that's been produced by some other kind of direction. On left
bottom, you also see the trigger readout schema for the new small wheel system. It's a
very complicated schema. Electronics is also based on many custom boards custom
elements. The schema goes from the front end here. On the on the left to the off
detector right. There are four custom asics developed for the system for the
front end. There are many front end boards. There are boards sitting on the
rim of the wheel this one reported in the pink box. And there is also off detector
electronics which is essentially based on ATCA modules. On slide seven, let's move
on the new small wheel status. The, about chambers and electronics for the first
wheel, on Side A. They’re already produced and are on track also for the second. And
indeed, many electronics parts have already completed their production the integration
activities are in full swing for both for Micromegas and for sTGC. As you can see
in the pictures on the left. When I say integration I mean assembly installation
connections but also software for DAQ and triggers as well they’re being developed
prior to COVID break it was on track for installing the first wheel before the
end of the year. And but you may see here in the bottom right that the two sectors are
already installed on the wheel since March. Let's move on the other on another
upgrade on slide eight, the BIS seven eight upgrade.
We just saw that new small wheel will cover a region in eta between 1.3 and 2.7
while the big wheel covers a region between one and 2.7. So, there is an intermediate
region between one and 1.3 that is not covered by the new small wheel. And
this region is only partially covered in the large sectors by the existing so called
EIL4 TGC endcap chambers. So the idea of the experiment was to install the
decision was to install new detectors in the BIS region. So only in the small sectors in
order to reduce the foreseen fake rate. This upgrade is made of 16 RPC chambers with
that are thin gap RPC triplets with one millimeter of gas gap instead of two and new
front end electronics and also, the existing 16 MDT detectors will be replaced
with small MDTs that are drift tubes with diameter of 15 millimeters instead of
30. And the detector production is ongoing As you may see on right picture photo, the
this is an RPC triplet in BB5 site and also the installation of the A side in principle
was scheduled to be done by summer maybe this is still the case while the C side is
postponed uhm Yes, the C side installation is postponed until long
shutdown three. This is also an important project, which is a pilot project for
phase two because the same MDT and RPC detector technology will be used when the
barrel inner layer will be equipped. Let's move on slide nine, the upgrades on the
liquid argon calorimeter and level one calo trigger system, there will be new front
end and back end boards for the calorimeter. These will allow to increase
the trigger tower granularity and have a good trigger performances even at the high pileup.
So this is the granularity for run one and run two and this is the new granularity for run
three. The aim of course is to keep a low trigger rate thanks to the background
rejection and low thresholds thanks to the high geometrical resolution which is
increased about the level one calo trigger and readout system. You can see the full
schema here on the bottom right. There are three posters on these on these items on
next Thursday and essentially the main feature are the new feature extractor
boards, the electron jet and global that process the data from the
electromagnetic calorimeter at a higher granularity. And in this case they will
perform more refined processing with respect to the previous runs, and also to
have a better discrimination between photons, the electrons taus and jets. Of
course, you can find many more details on these three projects about slide 9 ehm 10.
About the full TDAQ phase one upgrade. As I said, there will be an upgrade on the
level one calo.
There will be also an upgrade on level one topo, which is a new board that performs
topological algorithms on data coming from calorimeters and muons in the end cap
region. There will be the new sector logic board endcap sector logic board it will
receive inputs from the new muon detectors. That's why we need a new board.
New detectors are the new small wheel muon system and the RPC BIS and also inputs
from the outer layer of the tile calorimeter the extended barrel of tile calorimeter there will
be also poster on this on next Thursday and all these inputs will be used in order
to reduce the fate rate in the endcap as I already said about the central trigger
processor new muon to central trigger processor interface boards will be built.
These will manage the data transfer from the new boards. So essentially from
Level one Topo and new endcap sector logic I already discussed and also will have more
resources in order to process data and higher bandwidth to be tran uhm by using
optical links essentially about readout system. There will be the new Felix
readout system it acts like a router between the custom front end links and
commercial, multi gigabit network technology. In order to transfer data to
the appropriate destination. It interfaces with the timing trigger control TTC system and
the busy system. It will be used in phase one for the upgrades I already described.
The new small wheel BIS seven, eight and the liquid argon upgrades but we’ll be also the
standard system for the phase two for run four, okay. So, we are ready to move
to phase two. These are the items I will discuss, and their position in the experiment.
The first is new all silicon inner tracker also called ITK. The current ATLAS inner
detector was designed to operate for 10 years at the luminosity of 10 to 34 at an
average pile up of 23 and the level one rate of 100 kilohertz Of course using it at the
high luminosity LHC era will bring increased occupancies and bandwidth saturation
and also radiation damage. And so for this reason, a new all silicon tracking system
has been designed. It's made of two subsystems the strips which cover a region
in eta up to 2.7 which is made of four barrel layers and six endcap discs and the pixel subsystem
which covers a region up to eta four and is made of five barrel layers plus
inclined modules plus barrel and endcap rings the aim of ITK is to reach equal or better
performance than the existing detector in a much more difficult tracking
environment. And for example, to keep a high track reconstruction efficiency
and low rates of fake tracks. Just to give you some numbers on slide 13, I want to
give you some numbers and photos. To give you an idea about the huge ITK project the pixel
have more than 10,000 modules more than 33,000 front end chips more than 10 to
nine channels, and also strips have roughly 10 18 Ks modules and almost 60 millions of
channels. These are some photos or some designs of how the project is evolving.
Let's move on slide 14. About liquid argon calorimeter. The current electronic is not
compatible with phase two requests essentially for latency and trigger rates
as we will see later. And also the radiation requirement for Phase Two are
above the original design. So the idea is to keep the phase one upgrade boards, but
also build the new front end and back end electronics. In order to read the detector
at full granularity, and send the data off detector to the back end at 40 megahertz.
There's a poster on this. There was also a presentation today about the
high granularity timing detector HGTD it will be used to mitigate the pileup. And so, to
use high precision timing information to distinguish between collisions, it will be
installed in a space between the inner detector and the calorimeter endcap so
essentially in this zone and it will be based on silicon low gain avalanche
detector technology that will be used also by CMS. And with the timing
resolution less than 50 Pico seconds it will improve the forward object reconstruction
by complementing and helping the tracking capabilities of ITK in the forward
region essentially, but we’ll be also used for online and offline luminosity.
Let's move on slide 15. Another calorimeter the tile cal It's made of steel plates
and plastic scintillator tiles for the phase two upgrades a complete replacement
of on detector and off detector electronics is foreseen because of mainly two
reasons radiation damage and aging and but also to be compatible with the TDAQ
requirements, new architecture requirements and transfer the full data off
detector optically at 40 megahertz. Moreover, the roughly 10% of the photo
multipliers, the ones reading out the most exposed cells will be replaced the uhm
is foreseen an upgrade of low voltage power supply and also the high voltage distribution
system. And this is the full acquisition schema for the tile cal and the project is in
a very mature state and preproduction is expected already this year for several
subsystem. Thanks. Let's move on the muon detectors on slide 16. Just to
give you an overview of the system the upgrades foreseen for the muons have two
main objectives to reduce the trigger fake rate in the barrel and the end cap region
and to increase the geometry coverage in the barrel. In order to do this new
detectors will be installed in the barrel the RPCs plus sMDTs so if you look
at two pictures on the bottom, on the left for the small sectors, the old BIS MDTs
will be replaced with the new small MDTs plus RPCs exactly like the BIS 78
project while in the large sectors. The new RPC detectors will be mounted on top
of the existing BIL MDTs, because here we have a much more space also in
the end cap region, the TGC EIL four detector will be replaced. At the moment
there is a doublet there will be a triplet in order to allow more robust coincidence
algorithm. Please note also that for the small sectors there are the coil support
structures here that create coverage holes in the barrel middle layers as it
has been for run one and run two and it will be also in run three. And so these coverage holes
will be covered by these new layer of RPCs. Let's move on slide 17. For the level zero
muon trigger. So, the data from the RPCs TGC and the new small wheel detector
used in Phase One will be complemented with the new detectors with BI RPCs with
the EIL4 TGCs with the tile cal
tile calorimeter outer cells and with the small MDTS
By looking at the top left plots, we obtained two objectives essentially we are
covering all the regions in eta. So, essentially we are increasing the
geometrical acceptance on the barrel from 78% to 95%. And we can also reach an increased
selection efficiency in in reducing the fake triggers by making more robust
coincidences. In order to do this also the muon detectors boards will be designed
and installed they will allow full digital detector readout. So the data will be sent
off at 40 megahertz sent off detector. The bottom block shows the trigger readout
schema for the muon spectrometer, the barrel and endcap new off detector sector
logic. Will perform the trigger algorithm as usual. But now the system takes the
advantage from the higher latency and so also the MDT trigger processor is used will
be designed and used in order to help in mu identification and fake trigger rejection and
as I said that readout data are then sent to Felix Once the event is accepted and
validated
let's move on slide 18, the TDAQ system in phase two.
This is a very
short overview. In the picture, you see what is called the baseline schema for the
TDAQ. It's a two level architecture. The first level is the level zero where the
central trigger processor receives two minutes thanks receives data from the muon
system and calorimeters for Level zero level zero muon. It issues a level zero accept signal
which is the pink arrow which is sent back to the detectors and then data are read out
by the inner tracker the calorimeter and the muon system to Felix. The second level is
an high level trigger HLT. And here It is made of processor farms, a custom hardware called
HTT that uses the tracking data to refine the trigger algorithm. The trigger rate has to be at
one megahertz It was 100 kilohertz in run 1 and run 2 the latency has to be less than than 10
microseconds. it was 2.5 microseconds in run one and run two and the permanent storage has to be
performed at 10 kilohertz, under consideration is also level zero level one
architecture which will allow to scale system later if it is required by the physics
requirements or by the LHC hm HL-LHC performances, but the system has to be
designed Now, in order to allow also an evolution. Let's just focus on the level
zero architecture. there will be additional data from calorimeters and from
muons for the level zero calo together with the new phase one upgrades these three
there will be also another which is called the fFEX or forward features
extractors. For the muons The data from new small wheel will be also complemented with
the data from the MDTs and also for the rpcs to improve the trigger coverage
and efficiency. A new system will be the global trigger that will perform offline
like algorithms on full granularity on calorimeter data. It will make use of
topological criteria such as clustering, or photon and electron identification and
isolation, for the central trigger the muons to Central trigger interface designed
for phase one will be used also for phase two only the firmware will be upgraded while
the new central trigger processor will be developed and designed for phase two
about the DAQ and high level trigger the detector readout will be done at 1 megahertz
which is ten times
time is over this is my last This is my last slide
the readout throughput will be to be 5.2 terabytes per second which is 20 times more than today's
the DAQ system will be based on Felix the data flow will make buffering event building
and recording data and also the event filter as I said is based on hardware track trigger,
which is based on the associative memories or FPGAs. And these are my conclusions So,
essentially the large data set that can be collected will allow to perform a lot of precision
measurements both in the exploration of standard model and rare standard model processes
and for new phenomena, the phase one upgrades and phase two are Well ongoing phase one is
already almost completed and ready for installation while phase two upgrade is in
the prototype state design state. If you want more details here, I put a link with
all the published TDRs. Thanks. Sorry for being late.
Okay, thank you Vincenzo. Thank you for this rather extensive talk. I'm sure there must be
questions.
Remember to raise your hands
there are no question. I want to ask you one thing I didn't get. Yes. So what is the status
now for the new small wheels of the micro mega detectors, what is the status of the
installation?
Okay, the micro megas and also the TGC, the full new small wheel system, was a high
priority task. So even during the CERN COVID crisis say there was a task force
that was still working on the assembly and installation and connections, even when
the number of people allowed to enter CERN was very low. Then since last
week I think much more people entered.
I'm not sure
if the ehm if another sector was installed, so the idea is to install more uhm first the small sectors
like these two and then the largest. But of course if you want if you ask about micro
megas, micro megas has to be sandwiched with the TGCs. So it's a
matter of having everything at CERN and then to put everything back together to
make the all this stuff that I tried to put pictures here and then install on the
wheel. I think that there was not too much delay on the new small wheel because it was
a high priority task. I don't know much more details in reality. Okay, thanks.
So time for one question.