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Detectors for a new era of ATLAS physics

Mon, 08/11/2021 - 14:02
Detectors for a new era of ATLAS physics Katarina Anthony ccoman Mon, 11/08/2021 - 13:02

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will dramatically increase the rate of collisions in the ATLAS experiment. While offering an opportunity for physicists to explore some of the rarest processes in the universe, the large collision rate brings new challenges – in particular, higher radiation levels and significantly more data. The ATLAS collaboration is adapting to deal with these challenges by upgrading all parts of its detectors with new, state-of-the-art instruments.

“The Muon New Small Wheels (NSW) are the first new detectors in ATLAS specifically designed to handle high-luminosity conditions,” says ATLAS Spokesperson Andreas Hoecker. “The installation of the second – and final – NSW follows nearly a decade of dedicated efforts by ATLAS members, who designed, constructed and assembled this high-tech muon detector from scratch.”

Cutting-edge technology

The ATLAS NSW system is made up of two wheel-shaped detectors, sitting at opposite ends of the experimental cavern. Named in comparison to ATLAS’s 25-metre “big wheel” detectors, each NSW weighs more than 100 tonnes and is nearly 10 metres in diameter.

More important than size is function. The NSW detectors are at the forefront of detector design, using two innovative gaseous detector technologies: micromegas (MM) and small-strip thin-gap chambers (sTGC). These provide both fast and precise muon-tracking capabilities. “The improved spatial resolution allowed by the NSW will be especially critical for the ATLAS “trigger”, the system that decides which collision events to store and which to discard. The trigger will rely on the NSW’s excellent resolution to confirm whether a particle originated from the interaction point, thus reducing our chances of saving data from unwanted background events,” says Mario Antonelli, NSW Phase 1 Upgrade Project Leader.

The readout capabilities of the overall system are staggering: two million MM readout channels and 350,000 sTGC electronic readout channels. Each wheel has 16 sectors, each containing two layers of MM and sTGC chambers with four measurement planes apiece, providing the physicists with useful redundancy as they trace a muon’s track through the detectors.

Assembly of the NSW chambers at CERN. (Image: CERN)

The dance of detectors

While 2021 has seen the NSW detectors journey underground, this was not their first time on the move. “The NSW effort was multinational, with members from across the global ATLAS collaboration contributing to construction and design,” says Philipp Fleischmann, ATLAS Muon System Project Leader.

After the original wheels were officially retired, NSW “A” was driven from Building 191 to the ATLAS surface hall on 6 July and, six days later, lowered into the ATLAS cavern where it was moved into its final position between the calorimeter endcap cryostat and the endcap toroid magnets. This momentous occasion was repeated for the NSW “C” four months later, as it was lowered into the ATLAS cavern on 4 November.

“That the team managed to keep the project on track despite a global pandemic and the tragic loss of their project leader, Stephanie Zimmermann, is a testament to their incredible talent and dedication,” says ATLAS Technical Coordinator Ludovico Pontecorvo.

NSW “C” enters the ATLAS surface hall, located just above the experiment, on 14 October 2021. (Image: CERN)

New wheels in motion

The NSW detectors will be instrumental in Run 3 data taking, as a moderate increase in luminosity is already planned for the LHC. While waiting to see the wheels in action, the ATLAS collaboration turns its focus to the next major upgrades of the experiment. “The next long shutdown of the LHC (LS3, scheduled for 2025) will be the last before the HL-LHC begins operation,” says Francesco Lanni, ATLAS Upgrade Coordinator. “We have a lot to accomplish in the intervening years, including the construction and assembly of an entire new inner tracking system. But with each new upgrade, we get one step closer to the next chapter of LHC physics and the exciting discoveries that may lay within.”

­­­­­_________________

Key to the success of the New Small Wheel was its former project leader, ATLAS physicist Stephanie Zimmermann. Her sudden death in November 2020 left a hole in the tight-knit NSW family. In her honour – and wishing to fulfil her dream of seeing the NSW installed – a photo of Stephanie was attached to NSW “A” as it was lowered into the experiment.

A full obituary was published in tribute to Stephanie in the CERN Bulletin.

---
Learn more:

Wheels in motion for ATLAS upgrade, CERN Courier, October 2021

First ATLAS New Small Wheel nears completion, ATLAS News, June 2021

Watch the lowering of the New Small Wheel detector in 360°, live event, July 2021

­­­­­__________________

Read the original article on the ATLAS website

Detectors for a new era of ATLAS physics

Mon, 08/11/2021 - 14:02
Detectors for a new era of ATLAS physics Katarina Anthony ccoman Mon, 11/08/2021 - 13:02

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) will dramatically increase the rate of collisions in the ATLAS experiment. While offering an opportunity for physicists to explore some of the rarest processes in the universe, the large collision rate brings new challenges – in particular, higher radiation levels and significantly more data. The ATLAS collaboration is adapting to deal with these challenges by upgrading all parts of its detectors with new, state-of-the-art instruments.

“The Muon New Small Wheels (NSW) are the first new detectors in ATLAS specifically designed to handle high-luminosity conditions,” says ATLAS Spokesperson Andreas Hoecker. “The installation of the second – and final – NSW follows nearly a decade of dedicated efforts by ATLAS members, who designed, constructed and assembled this high-tech muon detector from scratch.”

Cutting-edge technology

The ATLAS NSW system is made up of two wheel-shaped detectors, sitting at opposite ends of the experimental cavern. Named in comparison to ATLAS’s 25-metre “big wheel” detectors, each NSW weighs more than 100 tonnes and is nearly 10 metres in diameter.

More important than size is function. The NSW detectors are at the forefront of detector design, using two innovative gaseous detector technologies: micromegas (MM) and small-strip thin-gap chambers (sTGC). These provide both fast and precise muon-tracking capabilities. “The improved spatial resolution allowed by the NSW will be especially critical for the ATLAS “trigger”, the system that decides which collision events to store and which to discard. The trigger will rely on the NSW’s excellent resolution to confirm whether a particle originated from the interaction point, thus reducing our chances of saving data from unwanted background events,” says Mario Antonelli, NSW Phase 1 Upgrade Project Leader.

The readout capabilities of the overall system are staggering: two million MM readout channels and 350,000 sTGC electronic readout channels. Each wheel has 16 sectors, each containing two layers of MM and sTGC chambers with four measurement planes apiece, providing the physicists with useful redundancy as they trace a muon’s track through the detectors.

Assembly of the NSW chambers at CERN. (Image: CERN)

The dance of detectors

While 2021 has seen the NSW detectors journey underground, this was not their first time on the move. “The NSW effort was multinational, with members from across the global ATLAS collaboration contributing to construction and design,” says Philipp Fleischmann, ATLAS Muon System Project Leader.

After the original wheels were officially retired, NSW “A” was driven from Building 191 to the ATLAS surface hall on 6 July and, six days later, lowered into the ATLAS cavern where it was moved into its final position between the calorimeter endcap cryostat and the endcap toroid magnets. This momentous occasion was repeated for the NSW “C” four months later, as it was lowered into the ATLAS cavern on 4 November.

“That the team managed to keep the project on track despite a global pandemic and the tragic loss of their project leader, Stephanie Zimmermann, is a testament to their incredible talent and dedication,” says ATLAS Technical Coordinator Ludovico Pontecorvo.

NSW “A” positioned in place inside the ATLAS experiment. (Image: CERN)

New wheels in motion

The NSW detectors will be instrumental in Run 3 data taking, as a moderate increase in luminosity is already planned for the LHC. While waiting to see the wheels in action, the ATLAS collaboration turns its focus to the next major upgrades of the experiment. “The next long shutdown of the LHC (LS3, scheduled for 2025) will be the last before the HL-LHC begins operation,” says Francesco Lanni, ATLAS Upgrade Coordinator. “We have a lot to accomplish in the intervening years, including the construction and assembly of an entire new inner tracking system. But with each new upgrade, we get one step closer to the next chapter of LHC physics and the exciting discoveries that may lay within.”

­­­­­_________________________________________

Key to the success of the New Small Wheel was its former project leader, ATLAS physicist Stephanie Zimmermann. Her sudden death in November 2020 left a hole in the tight-knit NSW family. In her honour – and wishing to fulfil her dream of seeing the NSW installed – a photo of Stephanie was attached to NSW “A” as it was lowered into the experiment.

A full obituary was published in tribute to Stephanie in the CERN Bulletin.

---
Learn more:

Wheels in motion for ATLAS upgrade, CERN Courier, October 2021

First ATLAS New Small Wheel nears completion, ATLAS News, June 2021

Watch the lowering of the New Small Wheel detector in 360°, live event, July 2021

­­­­­_________________________________________

Read the original article on the ATLAS website

Flexible and accessible, the HiRadMat facility celebrates its tenth anniversary

Fri, 05/11/2021 - 15:51
Flexible and accessible, the HiRadMat facility celebrates its tenth anniversary Nikolaos Charitonidis Pascal Simon ccoman Fri, 11/05/2021 - 14:51

HiRadMat (High-Radiation to Materials) has been a key European facility for material testing for ten years now. It is designed to provide high-intensity, high-momentum pulsed beams to an irradiation area where accelerator components, high-power targets and various other material samples can be tested.

“HiRadMat was originally conceived in 2009 as a test bench for the Large Hadron Collider (LHC) collimators at a time when ad hoc installations were the baseline for such tests. Management approval and the securing of EU funding in 2010 got the ball rolling for the irradiation facility, and the construction was successfully completed in 2011,” says Ilias Efthymiopoulos, the Project Leader for the HiRadMat construction. “A challenge in the building of HiRadMat was the dismantling of the old T1 target of the West Area and the T9 target of West Area Neutrino Facility. The special tools we developed as part of the dismantling campaign are now used widely at CERN.”

“From the start, strong emphasis was put on offering exceptionally flexible beamline optics,” explains Malika Meddahi, Deputy Director for Accelerators and Technology and former Project Leader for beamline design, construction and commissioning. “The beam is extracted from the Super Proton Synchrotron (SPS) using the same extraction channel as LHC beam 1, then sent down the existing TT60 transfer line, from which the HiRadMat primary beamline (TT66) branches off after about 200 metres, offering spot sizes of 0.2–4 mm to the various experiments in a flexible way.”

Following the first experiments (starting with the test of a tungsten powder target under a high-power pulsed beam), several facilities at CERN based their designs on the data provided by HiRadMat experiments. “In the field of beam interception, we have tested particle-producing target prototypes, conducted R&D on advanced materials and carried out investigations on refractory materials,” explains Marco Calviani, Leader of the Targets, Collimators and Dumps section.

Electro-optical beam position monitors (BPM), a special new BPM technology developed with RHUL in the framework of High-Luminosity LHC, tested at HiRadMat (Image: CERN)

From the beginning, HiRadMat has been part of Transnational Access programmes EuCARD, EuCARD-2 and ARIES, making the facility accessible to users from all over the world. Today, the facility provides up to 2 x 1016 protons per year. “For the past ten years, HiRadMat experiments have been pushing the frontiers of beam-to-material knowledge, with 42 experiments successfully completed,” says Nikos Charitonidis, from the Experimental Areas group, who is responsible for the facility at CERN and chair of its technical board.

Electro-optical BPM installation at TNC, ready to receive beam (Image: CERN)

HiRadMat experiments are evaluated according to scientific criteria by a board of external experts. Among these specialists is Bernie Riemer, chair of the board and scientist at Oak Ridge National Laboratory. “Our role allows us to witness exciting developments in technology, materials and fundamental research for the benefit of CERN and worldwide collaborators.” A key member of the board and its first chair was the late Nick Simos from Brookhaven National Laboratory, who passed away in 2020. “We lost a mentor, friend and leader who worked actively to incite members, users and CERN staff,” recalls Bernie.

The legacy of Nick and of the HiRadMat team is already strong, as Verena Kain, Leader of the SPS Operation section, stresses: “HiRadMat has certainly helped to further increase the flexibility and versatility of the CERN LHC injectors.”

The story will continue during Run 3, as it has in 2021 with three CERN experiments: BLM3, for the calibration and verification of the LHC beam loss monitors; Multimat2, a critical benchmark of collimator materials in view of the HL-LHC upgrades; and HED, an important validation of high-energy dump design materials. With the next upgrade coming up, aiming to prepare the facility for more luminous and energetic beams, HiRadMat still has its best days ahead of it. “Studies are ongoing to upgrade the layout and key beam elements in order to allow for maximum beam intensities and brightness thanks to the LHC Injectors Upgrade project, enabling the facility to address a number of new experiments that the community is eagerly awaiting,” says Markus Brugger, Experimental Areas Group Leader.

This article is dedicated to Nick Simos.

Flexible and accessible, the HiRadMat facility celebrates its tenth anniversary

Fri, 05/11/2021 - 15:51
Flexible and accessible, the HiRadMat facility celebrates its tenth anniversary Nikolaos Charitonidis Pascal Simon ccoman Fri, 11/05/2021 - 14:51

HiRadMat (High-Radiation to Materials) has been a key European facility for material testing for ten years now. It is designed to provide high-intensity, high-momentum pulsed beams to an irradiation area where accelerator components, high-power targets and various other material samples can be tested.

“HiRadMat was originally conceived in 2009 as a test bench for the Large Hadron Collider (LHC) collimators at a time when ad hoc installations were the baseline for such tests. Management approval and the securing of EU funding in 2010 got the ball rolling for the irradiation facility, and the construction was successfully completed in 2011,” says Ilias Efthymiopoulos, the Project Leader for the HiRadMat construction. “A challenge in the building of HiRadMat was the dismantling of the old T1 target of the West Area and the T9 target of West Area Neutrino Facility. The special tools we developed as part of the dismantling campaign are now used widely at CERN.”

“From the start, strong emphasis was put on offering exceptionally flexible beamline optics,” explains Malika Meddahi, Deputy Director for Accelerators and Technology and former Project Leader for beamline design, construction and commissioning. “The beam is extracted from the Super Proton Synchrotron (SPS) using the same extraction channel as LHC beam 1, then sent down the existing TT60 transfer line, from which the HiRadMat primary beamline (TT66) branches off after about 200 metres, offering spot sizes of 0.2–4 mm to the various experiments in a flexible way.”

Following the first experiments (starting with the test of a tungsten powder target under a high-power pulsed beam), several facilities at CERN based their designs on the data provided by HiRadMat experiments. “In the field of beam interception, we have tested particle-producing target prototypes, conducted R&D on advanced materials and carried out investigations on refractory materials,” explains Marco Calviani, Leader of the Targets, Collimators and Dumps section.

Electro-optical beam position monitors (BPM), a special new BPM technology, being tested at HiRadMat (Image: CERN)

From the beginning, HiRadMat has been part of Transnational Access programmes EuCARD, EuCARD-2 and ARIES, making the facility accessible to users from all over the world. Today, the facility provides up to 2 x 1016 protons per year. “For the past ten years, HiRadMat experiments have been pushing the frontiers of beam-to-material knowledge, with 42 experiments successfully completed,” says Nikos Charitonidis, from the Experimental Areas group, who is responsible for the facility at CERN and chair of its technical board.

Electro-optical BPM installation at TNC, ready to receive beam (Image: CERN)

HiRadMat experiments are evaluated according to scientific criteria by a board of external experts. Among these specialists is Bernie Riemer, chair of the board and scientist at Oak Ridge National Laboratory. “Our role allows us to witness exciting developments in technology, materials and fundamental research for the benefit of CERN and worldwide collaborators.” A key member of the board and its first chair was the late Nick Simos from Brookhaven National Laboratory, who passed away in 2020. “We lost a mentor, friend and leader who worked actively to incite members, users and CERN staff,” recalls Bernie.

The legacy of Nick and of the HiRadMat team is already strong, as Verena Kain, Leader of the SPS Operation section, stresses: “HiRadMat has certainly helped to further increase the flexibility and versatility of the CERN LHC injectors.”

The story will continue during Run 3, as it has in 2021 with three CERN experiments: BLM3, for the calibration and verification of the LHC beam loss monitors; Multimat2, a critical benchmark of LHC collimators; and HED, an important validation of high-energy dump design materials. With the next upgrade coming up, aiming to prepare the facility for more luminous and energetic beams, HiRadMat still has its best days ahead of it. “Studies are ongoing to upgrade the layout and key beam elements in order to allow for maximum beam intensities and brightness thanks to the LHC Injectors Upgrade project, enabling the facility to address a number of new experiments that the community is eagerly awaiting,” says Markus Brugger, Experimental Areas Group Leader.

This article is dedicated to Nick Simos.

Bringing new life to ATLAS data

Fri, 22/10/2021 - 12:08
Bringing new life to ATLAS data ATLAS collaboration thortala Fri, 10/22/2021 - 11:08

The ATLAS collaboration is breathing new life into its LHC Run 2 dataset, recorded from 2015 to 2018. Physicists will be reprocessing the entire dataset – nearly 18 PB of collision data – using an updated version of the ATLAS offline analysis software (Athena). Not only will this improve ATLAS physics measurements and searches, it will also position the collaboration well for the upcoming challenges of Run 3 and beyond.

Athena converts raw signals recorded by the ATLAS experiment into more simplified datasets for physicists to study. Its new-and-improved version has been in development for several years and includes multi-threading capabilities, more complex physics-analysis functions and improved memory consumption.

“Our aim was to significantly reduce the amount of memory needed to run the software, widen the types of physics analyses it could do and – most critically – allow current and future ATLAS datasets to be analysed together,” says Zach Marshall, ATLAS Computing Coordinator. “These improvements are a key part of our preparations for future high-intensity operations of the LHC – in particular the High-Luminosity LHC (HL-LHC) run beginning around 2028, which will see ATLAS’s computing resources in extremely high demand.”

This latest version of Athena already makes good headway in reducing the computing resources required for data analysis. For example, the computationally intensive job of taking individual signals from the inner detector and chaining them together to form particle tracks is now two to four times faster. Less disk space is needed to store the results and overall the software runs more smoothly.

The software improvements also feature new ways for physicists to study their data. For example, researchers will now, by default, be able to look for tracks that originate away from the collision point. These could be signatures of particles with long lifetimes and may lead to evidence of exciting beyond-the-Standard-Model physics processes. While such searches were possible with the earlier version of the ATLAS software, the heavy computing resources they required meant they could not always be carried out.

Finally, physicists have also made improvements to the databases containing all of the time-dependent status information of the detector components. These databases – on which Athena runs – now incorporate an improved understanding of the detector’s operation during Run 2. “Every data-taking period is an opportunity for us to learn more about the detector and its subsystems,” says Song-Ming Wang, ATLAS Data Preparation Coordinator. “Revisiting these databases with the benefit of hindsight will allow us to provide even better performance.”

With the new Athena software now up and running, researchers have set out to reprocess the entire Run 2 dataset. This will take several months, as the dataset is quite substantial.

The expected results will be well worth this effort: ATLAS will have a significantly improved dataset that will allow for crisper measurements, more powerful searches and simpler combinations of past and future data.

Read the original article on the ATLAS website

Bringing new life to ATLAS data

Fri, 22/10/2021 - 12:08
Bringing new life to ATLAS data ATLAS collaboration thortala Fri, 10/22/2021 - 11:08

The ATLAS collaboration is breathing new life into its LHC Run 2 dataset, recorded from 2015 to 2018. Physicists will be reprocessing the entire dataset – nearly 18 PB of collision data – using an updated version of the ATLAS offline analysis software (Athena). Not only will this improve ATLAS physics measurements and searches, it will also position the collaboration well for the upcoming challenges of Run 3 and beyond.

Athena converts raw signals recorded by the ATLAS experiment into more simplified datasets for physicists to study. Its new-and-improved version has been in development for several years and includes multi-threading capabilities, more complex physics-analysis functions and improved memory consumption.

“Our aim was to significantly reduce the amount of memory needed to run the software, widen the types of physics analyses it could do and – most critically – allow current and future ATLAS datasets to be analysed together,” says Zach Marshall, ATLAS Computing Coordinator. “These improvements are a key part of our preparations for future high-intensity operations of the LHC – in particular the High-Luminosity LHC (HL-LHC) run beginning around 2028, which will see ATLAS’s computing resources in extremely high demand.”

This latest version of Athena already makes good headway in reducing the computing resources required for data analysis. For example, the computationally intensive job of taking individual signals from the inner detector and chaining them together to form particle tracks is now two to four times faster. Less disk space is needed to store the results and overall the software runs more smoothly.

The software improvements also feature new ways for physicists to study their data. For example, researchers will now, by default, be able to look for tracks that originate away from the collision point. These could be signatures of particles with long lifetimes and may lead to evidence of exciting beyond-the-Standard-Model physics processes. While such searches were possible with the earlier version of the ATLAS software, the heavy computing resources they required meant they could not always be carried out.

Finally, physicists have also made improvements to the databases containing all of the time-dependent status information of the detector components. These databases – on which Athena runs – now incorporate an improved understanding of the detector’s operation during Run 2. “Every data-taking period is an opportunity for us to learn more about the detector and its subsystems,” says Song-Ming Wang, ATLAS Data Preparation Coordinator. “Revisiting these databases with the benefit of hindsight will allow us to provide even better performance.”

With the new Athena software now up and running, researchers have set out to reprocess the entire Run 2 dataset. This will take several months, as the dataset is quite substantial.

The expected results will be well worth this effort: ATLAS will have a significantly improved dataset that will allow for crisper measurements, more powerful searches and simpler combinations of past and future data.

Read the original article on the ATLAS website

The four LHC experiments are getting ready for pilot beams

Mon, 18/10/2021 - 16:16
The four LHC experiments are getting ready for pilot beams Cristina Agrigoroae cagrigor Mon, 10/18/2021 - 15:16 First Physics at CERN Control Room (Image: CERN)

Update: The first pilot beams circulated in the LHC on 19 October 2021. On 26 October, there were low-intensity test collisions at an injection energy of 450 GeV per beam and stable collisions of proton beams were declared on the morning of 27 October.

Since 2019, many places at CERN have been operating like beehives to complete the scheduled upgrades for the second long shutdown (LS2) of the accelerator complex. This period of intense work is now coming to an end with the injection of the first pilot beams into the LHC. This major milestone will be featured during a live event on CERN’s social media channels on 20 October at 4 pm (CEST).

The pilot beams are part of the commissioning of the LHC machine in preparation for its Run 3, starting in 2022. With an integrated luminosity equal to the two previous runs combined, the four LHC experiments will be able to perform even more precise measurements. Yet, to stay apace with the accelerator’s improved vigour, all of them had to undergo a series of upgrades and transformations.

After the refurbished Time Projection Chamber (TPC) and the revamped Miniframe joined the ALICE detector in the cavern, the reinstallation of its new Muon Forward Tracker subdetector followed. In May, a new Inner Tracking System (ITS), the largest pixel detector ever built, took the seat of the previous one, between the beam pipe and the TPC. The final piece of the ALICE puzzle – the Fast Interaction Trigger (FIT) – was installed in July.

At ATLAS, among the ongoing works, the muon spectrometer was upgraded, notably with the installation of one of the two New Small Wheels, which uses new technologies such as the novel small-strip Thin Gap Chambers (sTGC) and the Micromegas detectors. Its twin will be lowered into the detector’s cavern in November.

In 2020, the CMS experiment completed the installation of the first GEM (Gas Electron Multiplier) station, the brand new sub-detector system for detecting muons in the region closest to the beam pipe. This year, a new, redesigned beam pipe with a new vacuum pumping group was installed. Over the summer, after its design was improved and its innermost layer replaced, the Pixel Tracker was installed at the centre of the CMS detector, followed by the Beam Radiation, Instrumentation and Luminosity (BRIL) sub-detectors.

As for the LHCb experiment, an important metamorphosis happened during these two years. A new scintillating-fibre particle-tracking detector (SciFi) and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2, were installed this year, before the recommissioning of the beam pipe. The installation of a faster Vertex Locator (VELO) is planned for the coming months.

The first proton beams circulated in CERN’s accelerator chain in December last year, with the first beam being injected into the PS Booster (PSB), connecting it for the first time to the new Linac4. The Proton Synchrotron followed, accelerating its first beam in March, while the Super Proton Synchrotron (SPS) saw its first beams accelerated in May.

The four LHC experiments are getting ready for pilot beams

Mon, 18/10/2021 - 16:16
The four LHC experiments are getting ready for pilot beams Cristina Agrigoroae cagrigor Mon, 10/18/2021 - 15:16 First Physics at CERN Control Room (Image: CERN)

Since 2019, many places at CERN have been operating like beehives to complete the scheduled upgrades for the second long shutdown (LS2) of the accelerator complex. This period of intense work is now coming to an end with the injection of the first pilot beams into the LHC. This major milestone will be featured during a live event on CERN’s social media channels on 20 October at 4 pm (CEST).

The pilot beams are part of the commissioning of the LHC machine in preparation for its Run 3, starting in 2022. With an integrated luminosity equal to the two previous runs combined, the four LHC experiments will be able to perform even more precise measurements. Yet, to stay apace with the accelerator’s improved vigour, all of them had to undergo a series of upgrades and transformations.

After the refurbished Time Projection Chamber (TPC) and the revamped Miniframe joined the ALICE detector in the cavern, the reinstallation of its new Muon Forward Tracker subdetector followed. In May, a new Inner Tracking System (ITS), the largest pixel detector ever built, took the seat of the previous one, between the beam pipe and the TPC. The final piece of the ALICE puzzle – the Fast Interaction Trigger (FIT) – was installed in July.

At ATLAS, among the ongoing works, the muon spectrometer was upgraded, notably with the installation of one of the two New Small Wheels, which uses new technologies such as the novel small-strip Thin Gap Chambers (sTGC) and the Micromegas detectors. Its twin will be lowered into the detector’s cavern in November.

In 2020, the CMS experiment completed the installation of the first GEM (Gas Electron Multiplier) station, the brand new sub-detector system for detecting muons in the region closest to the beam pipe. This year, a new, redesigned beam pipe with a new vacuum pumping group was installed. Over the summer, after its design was improved and its innermost layer replaced, the Pixel Tracker was installed at the centre of the CMS detector, followed by the Beam Radiation, Instrumentation and Luminosity (BRIL) sub-detectors.

As for the LHCb experiment, an important metamorphosis happened during these two years. A new scintillating-fibre particle-tracking detector (SciFi) and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2, were installed this year, before the recommissioning of the beam pipe. The installation of a faster Vertex Locator (VELO) is planned for the coming months.

The first proton beams circulated in CERN’s accelerator chain in December last year, with the first beam being injected into the PS Booster (PSB), connecting it for the first time to the new Linac4. The Proton Synchrotron followed, accelerating its first beam in March, while the Super Proton Synchrotron (SPS) saw its first beams accelerated in May.

Now, with the LHC at its nominal temperature (1.9 K), the first pilot beams will be circulated on 18 October. Join the live event on YouTube and Facebook to follow the first injection of proton beams into the LHC after a two-year-long shutdown.

Successful beam pipe installation at LHCb

Mon, 18/10/2021 - 11:51
Successful beam pipe installation at LHCb Cristina Agrigoroae cagrigor Mon, 10/18/2021 - 10:51 The stainless-steel section of the LHCb beam pipe is lifted up to the beamline with a crane and put in place between the filters of the muon system. (Image: CERN)

The LHC experiments are nearing the completion of maintenance and upgrade works carried out in the framework of the second long shutdown of CERN’s accelerator complex. Of all the experiments, LHCb is undergoing the most significant metamorphosis during these two years, namely the installation of a faster Vertex Locator (VELO), a new scintillating-fibre particle-tracking detector (SciFi), and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2. While the installation of LHCb’s subdetectors and infrastructure in preparation for commissioning is still under way, its beampipe was successfully reinstalled over the summer, marking a milestone in the detector’s preparation for Run 3 of the LHC.

The LHCb beam pipe has a conical shape through the whole of the LHCb detector, which makes it different from that of the other experiments. Along its total length of 19 m, its diameter ranges from 50 mm close to the LHCb interaction point to 380 mm in the experiment’s muon system. The beam pipe is composed of four sections, all of different lengths. Three of these sections are made of beryllium and measure 11.6 m, giving LHCb the longest beryllium beam pipe of all the LHC experiments. The last and biggest section is made of stainless steel. Both the shape and material of the beam pipe were chosen to optimise its transparency to particles emerging from the collisions that take place at the LHC. 

The beam pipe has a spider-web-like support structure in the aperture of the LHCb magnet, with beryllium collars and carbon-fibre ropes and rods ensuring that the amount of material is kept to a minimum. Installed during the first long shutdown, it was the first such structure ever used in an experiment and remains unique in the world today. The support structure may seem fragile, but is able to keep the beam pipe in place under the huge force that it exerts on itself when under vacuum.

The smallest of the beryllium sections is slid inside its spider-web-like support (Image: CERN)

The installation of the LHCb beam pipe, which involved engineers and technicians across multiple departments, started in April. The first smaller section was inserted through the RICH1 subdetector and connected to the VELO vacuum tank surrounding the interaction point. The installation and careful alignment of the spider-web-like structure followed in mid-July. The remaining sections were installed afterwards in a well-defined order: first, the longest (7 m) beryllium section was slid through the inner cylindrical sheath of the RICH2 subdetector. Then, the stainless-steel cone, the heaviest (160 kg) and biggest section, was lifted up to the beamline with a crane and then slid into place in the centre of the muon system. Finally, the lightest beryllium section (about 4 kg) was carefully installed by hand, sliding it into place on its spider-web support in the magnet.

Once the sections had been connected with bellows and checks had been carried out to make sure that there were no leaks in the connections, the bake-out procedure to improve the quality of the vacuum started in mid-August. For this step, the beam pipe was wrapped in heating blankets, allowing it to be heated up to 250 °C. The VELO vacuum tank and the very thin radio-frequency foil that separates the LHCb detector vacuum from the LHC beam vacuum were also heated at the same time as the beam pipe. After final checks of the vacuum quality, the heating blankets were removed and the beam pipe was filled with neon gas at atmospheric pressure to keep it ready for beams to circulate in October.

This video is available on CDS.

Successful beam pipe installation at LHCb

Mon, 18/10/2021 - 11:51
Successful beam pipe installation at LHCb cagrigor Mon, 10/18/2021 - 10:51 The stainless-steel section of the LHCb beam pipe is lifted up to the beamline with a crane and put in place between the filters of the muon system. (Image: CERN)

The LHC experiments are nearing the completion of maintenance and upgrade works carried out in the framework of the second long shutdown of CERN’s accelerator complex. Of all the experiments, LHCb is undergoing the most significant metamorphosis during these two years, namely the installation of a faster Vertex Locator (VELO), a new scintillating-fibre particle-tracking detector (SciFi), and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2. While the installation of LHCb’s subdetectors and infrastructure in preparation for commissioning is still under way, its beampipe was successfully reinstalled over the summer, marking a milestone in the detector’s preparation for Run 3 of the LHC.

The LHCb beam pipe has a conical shape through the whole of the LHCb detector, which makes it different from that of the other experiments. Along its total length of 19 m, its diameter ranges from 50 mm close to the LHCb interaction point to 380 mm in the experiment’s muon system. The beam pipe is composed of four sections, all of different lengths. Three of these sections are made of beryllium and measure 11.6 m, giving LHCb the longest beryllium beam pipe of all the LHC experiments. The last and biggest section is made of stainless steel. Both the shape and material of the beam pipe were chosen to optimise its transparency to particles emerging from the collisions that take place at the LHC. 

The beam pipe has a spider-web-like support structure in the aperture of the LHCb magnet, with beryllium collars and carbon-fibre ropes and rods ensuring that the amount of material is kept to a minimum. Installed during the first long shutdown, it was the first such structure ever used in an experiment and remains unique in the world today. The support structure may seem fragile, but is able to keep the beam pipe in place under the huge force that it exerts on itself when under vacuum.

The smallest of the beryllium sections is slid inside its spider-web-like support (Image: CERN)

The installation of the LHCb beam pipe, which involved engineers and technicians across multiple departments, started in April. The first smaller section was inserted through the RICH1 subdetector and connected to the VELO vacuum tank surrounding the interaction point. The installation and careful alignment of the spider-web-like structure followed in mid-July. The remaining sections were installed afterwards in a well-defined order: first, the longest (7 m) beryllium section was slid through the inner cylindrical sheath of the RICH2 subdetector. Then, the stainless-steel cone, the heaviest (160 kg) and biggest section, was lifted up to the beamline with a crane and then slid into place in the centre of the muon system. Finally, the lightest beryllium section (about 4 kg) was carefully installed by hand, sliding it into place on its spider-web support in the magnet.

Once the sections had been connected with bellows and checks had been carried out to make sure that there were no leaks in the connections, the bake-out procedure to improve the quality of the vacuum started in mid-August. For this step, the beam pipe was wrapped in heating blankets, allowing it to be heated up to 250 °C. The VELO vacuum tank and the very thin radio-frequency foil that separates the LHCb detector vacuum from the LHC beam vacuum were also heated at the same time as the beam pipe. After final checks of the vacuum quality, the heating blankets were removed and the beam pipe was filled with neon gas at atmospheric pressure to keep it ready for beams to circulate in October.

Watch the renovation of CERN’s East Area

Tue, 12/10/2021 - 19:53
Watch the renovation of CERN’s East Area Naomi Dinmore thortala Tue, 10/12/2021 - 18:53

CERN’s East Area has hosted a variety of fixed-target experiments since the 1950s, using four beamlines from the Proton Synchrotron (PS).

Over the past two years, the experimental area – CERN’s second largest – has undergone a complete makeover. New instrumentation and beamline configuration have improved the precision of data collection, and new magnets and power convertors have drastically reduced the area’s energy consumption.

As the beams return to the accelerator complex, the East Area’s experiments are taking physics measurements again and the facility’s central role in the modern physics landscape has been restored.

Watch a time-lapse video condensing two years of the East Area renovations into two minutes below.

(Video: CERN)

This video is available on CDS. 

Watch the renovation of CERN’s East Area

Tue, 12/10/2021 - 19:53
Watch the renovation of CERN’s East Area Naomi Dinmore thortala Tue, 10/12/2021 - 18:53

CERN’s East Area has hosted a variety of fixed-target experiments since the 1950s, using four beamlines from the Proton Synchrotron (PS).

Over the past two years, the experimental area – CERN’s second largest – has undergone a complete makeover. New instrumentation and beamline configuration have improved the precision of data collection, and new magnets and power convertors have drastically reduced the area’s energy consumption.

As the beams return to the accelerator complex, the East Area’s experiments are taking physics measurements again and the facility’s central role in the modern physics landscape has been restored.

Watch a time-lapse video condensing two years of the East Area renovations into two minutes below.

(Video: CERN)