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  • richardmitnick 10:17 am on February 28, 2020 Permalink | Reply
    Tags: "Stunning Images Capture Cosmic Ray Tracks", , , Cosmic rays are made mostly from the result of supernovae explosions and reaching us at nearly the speed of light., Losing more energy as it travels round and round the particle creates the curious circles in the images called “loopers.”, Particles with no electric charge always move in straight lines; however they cannot even be seen by the detector., RHIC, , STAR is only able to track charged particles which get pulled by the the detector’s magnetic field creating a curve., The “heart” of the STAR detector is its Time Projection Chamber- a four-meter-wide 4.2-meter-long cylinder filled with a gas mixture of argon and methane.   

    From Brookhaven National Lab: “Stunning Images Capture Cosmic Ray Tracks” 

    From Brookhaven National Lab

    February 26, 2020
    Erika Peters
    epeters@bnl.gov

    The beauty in science shines through at RHIC’s STAR detector [below] and makes a cosmic connection.

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    To help calibrate the STAR detector, physicists track and capture images of showers of cosmic rays streaming from space. Can you pick out which image shows tracks from a particle collision at RHIC (hint: the collision occurred at the center of the detector)?

    These images capture the movement and collisions of “cosmic rays”—mysterious particles originating somewhere in deep space—as they stream through the STAR detector at the Relativistic Heavy Ion Collider (RHIC) [below]. The results are profoundly beautiful.

    The rays, made mostly from the result of supernovae explosions and reaching us at nearly the speed of light, are not just things of beauty. Physicists conducting research at RHIC—a U.S. Department of Energy Office of Science user facility for nuclear physics research at Brookhaven National Laboratory—use their signals as a tool for calibrating the massive detectors collecting data for the collider’s physics experiments.

    The “heart” of the STAR detector is its Time Projection Chamber, a four-meter-wide, 4.2-meter-long cylinder filled with a gas mixture of argon and methane, explained Irakli Chakaberia, a research scientist on the STAR experiment. Each of the detector’s endcaps has 12 “sectors,” each with 72 padrows that sense electric charge, acting as a camera that can capture over 2,000 images a second. Tracing the trails of a shower of cosmic rays passing through the gas helps scientists know if their detector components are all working correctly.

    The higher the energy of the original cosmic track, the bigger the proliferation of the shower, creating what appear to be more “lively” images with many tracks in the chamber. How linear the path appears helps show the particle’s speed—the faster the particle moves, the straighter its path. Particles with no electric charge always move in straight lines; however, they cannot even be seen by the detector. STAR is only able to track charged particles, which get pulled by the the detector’s magnetic field, creating a curve. Those with lower momentum, called “soft” particles, are pulled more by the detector’s magnets and curve more than faster ones.

    “Based on the direction of the curve, we can tell whether the particle is positively or negatively charged,” Chakaberia said.

    When a cosmic ray particle collides with an atom of the gas in the detector, it might produce a “softer” particle moving with lower energy. Losing more energy as it travels round and round, the particle creates the curious circles in the images called “loopers.” Sometimes in the initial cascade, there are particles “soft” enough to loop around on their own.

    Even though physicists use powerful computers to analyze data from STAR, “nothing replaces an actual human eye,” Chakaberia said.

    “For example, when looking at some cosmic data, there was a case where tens of tracks were reconstructed in a single detector sector,” Chakaberia said. “This could, in principle, happen, but after checking the event display by eye it was obvious that it was a result of noise in that sector. The software couldn’t distinguish between the noise and real events to some degree. So these track displays help a lot to figure out what’s going on.”

    After cosmic rays have done their job testing and calibrating, STAR is ready to capture the thousands of tracks produced by ion collisions at RHIC. To increase the chance of two ions colliding, billions are aimed at each other with each pass through the detector, and the tracks reveal more of the beauty and the art that can be found in science. In this case, all the particle tracks emerge from the center of the detector, where the collision takes place. (Can you find the one ion-collision event in the images shown here?)

    Nuclear physicists analyze the ion-collision tracks to learn about a remarkable state of matter created in RHIC’s heavy-ion collisions. This “quark-gluon plasma” is a soup of particles that mimics what the universe was like just after the Big Bang. It’s a kind of cosmic connection: Scientists use a detector calibrated by particles from the cosmos to learn more about the marvelous and mystifying universe that created them.

    Research at RHIC/STAR is funded by the DOE Office of Science and by funders of the STAR collaboration listed here.

    See the full article here .


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  • richardmitnick 8:16 am on June 7, 2019 Permalink | Reply
    Tags: Accelerator physicists have demonstrated a groundbreaking technique using bunches of electrons to keep beams of particles cool at the Relativistic Heavy Ion Collider, , Electron Bunches Keep Ions Cool at RHIC, RHIC, The team had to build and commission a new state-of-the-art electron accelerator that would fit inside the RHIC tunnel., This included using more compact radiofrequency (RF) acceleration technology rather than the standard direct-current (DC) method used in all previous electron-cooling setups., World's first demonstration of "bunched-beam" electron cooling at low energy in RHIC opens the possibility of using this technique at high energies for a variety of applications.   

    From Brookhaven National Lab: “Electron Bunches Keep Ions Cool at RHIC” 

    From Brookhaven National Lab

    6.7.19
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    World’s first demonstration of “bunched-beam” electron cooling at low energy in RHIC opens the possibility of using this technique at high energies for a variety of applications.

    1
    Some members of the Low Energy RHIC electron Cooling (LEReC) team in the Main Control Room of Brookhaven Lab’s Collider-Accelerator Department. The team successfully demonstrated a bunched-beam electron cooling technique at RHIC, opening up the possibility of applying this technique to produce high-quality ion beams at high energies.

    Accelerator physicists have demonstrated a groundbreaking technique using bunches of electrons to keep beams of particles cool at the Relativistic Heavy Ion Collider (RHIC)—a U.S. Department of Energy Office of Science user facility for nuclear physics research at Brookhaven National Laboratory. This “bunched-beam” electron cooling technique will enable higher particle collision rates at RHIC, where scientists study the collision debris to learn about the building blocks of matter as they existed just after the Big Bang.

    2
    Brookhaven Lab engineer Mathew Paniccia next to the LEReC cooling sections. Electrons have successfully cooled bunches of ions in these cooling sections of the Relativistic Heavy Ion Collider (RHIC).

    Brookhaven’s accelerator team is testing the method at the collider’s lowest energies—a regime where data has been scarce yet is crucial to understanding how the particles that filled the early universe transformed into the ordinary matter that makes up our world today.

    “The low-energy conditions are actually the most challenging for this technique,” said Alexei Fedotov, the Brookhaven Lab accelerator physicist who led the effort and the team of nearly 100 people who made it happen.

    “Now that we’ve demonstrated bunched-beam cooling in the most challenging energy situation, it opens the possibility for applying these same principles at higher energies—including at a possible future Electron-Ion Collider,” he said.

    Conquering challenges

    3
    A schematic of the LEReC system, which includes many significant advances in accelerator science. When light from a laser setup outside the RHIC tunnel strikes the photocathode of a unique direct current (DC) photocathode gun, it produces bunches of electrons that are then accelerated by a superconducting radiofrequency (SRF) cavity and transported into cooling sections of RHIC. Here the cold electrons are precisely matched with RHIC’s ion bunches in one RHIC ring, then the other, to extract heat and keep the ions tightly packed with the aim of maximizing collision rates.

    The accomplishment builds on an idea invented just over 50 years ago by Russian physicist Gersh Budker—namely, using a beam of electrons (which are inherently cooler than larger particles moving at the same speed) to extract heat from a beam of larger particles. This keeps the particles tightly packed and more likely to collide. But the Brookhaven version includes a series of first-in-the-world achievements and innovations even experts in the field doubted could succeed so quickly.

    “There were many physics and engineering challenges to overcome,” Fedotov noted.

    The team had to build and commission a new state-of-the-art electron accelerator that would fit inside the RHIC tunnel—which included using more compact radiofrequency (RF) acceleration technology rather than the standard direct-current (DC) method used in all previous electron-cooling setups. And because RHIC’s ions circulate as periodic bunches of particles, not a continuous stream, the electrons had to be produced in pulses that matched up with those bunches—not just in timing but also in energy and trajectory—all while maintaining their intrinsic coolness. Plus, because RHIC is really two accelerators, with ion beams moving in opposite directions in two beampipes, the physicists had to figure out how to cool both beams with the same stream of electrons!

    “Otherwise we would have had to build two of these electron accelerators,” Fedotov said.

    “It’s actually a huge installation made of many complex components, including 100 meters of beamline where the accelerated electrons propagate with the ions in one RHIC beam to extract their heat, then make a 180-degree turn to cool the ions of the other RHIC beam moving in the opposite direction. That has never been done before!”

    Generating electrons

    4
    Joseph Tuozzolo, the head engineer for the LEReC project, stands next to a warm radiofrequency cavity used in the project.

    To generate and rapidly accelerate these precision electron bunches, the team used a laser-activated photocathode electron gun followed by an accelerating RF cavity. The gun uses a high-frequency high-power laser and Brookhaven-designed photocathodes that are transported 12-at-a-time in a vacuum chamber from Brookhaven’s Instrumentation Division to the RHIC tunnel. Once at RHIC, the vacuum chamber can rotate like a Ferris wheel to switch out photocathodes as they wear out while RHIC is running, enabling the gun to run at high current for long-term operation when access to RHIC is limited.

    “When we first talked about this design, in 2015, this was only a drawing!” Fedotov said. “Now we are routinely using it.”

    The green laser that triggers the photocathodes to emit pulses of electrons is also the first of its kind—the highest average power green laser ever generated by a single fiber-based laser. Precision alignment and trimming of the laser pulses controls the frequency of the electron bunches generated for cooling.

    5
    Members of Collider-Accelerator Department vacuum group next to the cathode insertion device (l to r): Mike Nicoletta, Kirk Sinclair, and Ken Decker.

    The laser and photocathode gun produced the first electron pulses in May 2017. Then, after commissioning the first seven meters of beamline (the injector for the accelerator) at end of 2017, the team installed 100 meters of beamline, including five RF cavities and straight cooling sections covered by several layers of magnetic shielding, in January 2018. They then spent last year commissioning the full electron accelerator.

    Keeping it cool

    “The main challenge was delivering a beam with all the properties required for cooling—meaning small relative velocities in all directions, with matching energies and small angles—and then propagating this very low-energy electron beam along 100 meters of beam transport line while maintaining those properties,” said Dmitry Kayran, the accelerator physicist who led the commissioning effort.

    6
    Brookhaven Lab engineer Jean Clifford Brutus next to a deflecting radiofrequency cavity he helped to design and install for the LEReC project.

    Kayran described the work on simulations that went into optimizing beam parameters, which guided the installation of beam-monitoring instruments, which in turn determined the placement of the RF acceleration cavities.

    “Due to acceleration, beam quality can deteriorate, so you need this monitoring and careful adjustments to keep the energy spread as low as possible,” Kayran said.

    “Design of the cooling sections for Low-Energy RHIC electron Cooling (LEReC) is unique,” said accelerator physicist Sergei Seletskiy, who led that part of the effort. “Preserving beam quality in these cooling sections of both RHIC rings is a challenge, and again something that’s been demonstrated for the first time with this project.

    “Many unique features and challenges of our project are related to the fact that, for the first time in 50 years, we are applying electron cooling directly at ion-collision energy,” he noted. “Seeing all this tying together and working to cool ions with bunched electron beams and in two collider rings at once is amazing. This is a big achievement in accelerator physics!”

    7
    Collider-Accelerator Department engineers and technicians with high-tech custom electronics equipment required for successful beam operations (from rear, l to r): Loralie Smart, Linh Nguyen, Kayla Hernandez, Geetha Narayan, Zeynep Altinbas, Theodoro Samms.

    The next step will be to show that the cooling enhances collision rates in next year’s RHIC low-energy collisions—and then extracting the data and what they reveal about the building blocks of matter.

    With a bunched-beam electron cooling technique now experimentally demonstrated at Brookhaven Lab, its application to high-energy cooling can open new possibilities by producing high-quality hadron beams that are required for several future accelerator physics projects, including the proposed Electron-Ion Collider (EIC).

    LEReC was funded by the DOE Office of Science and benefitted from the help and expertise of many in Brookhaven Lab’s Collider-Accelerator Department and Instrumentation Division, as well as contributions from Fermi National Accelerator Laboratory, Argonne National Laboratory, Thomas Jefferson National Accelerator Facility, and Cornell University.

    See the full article here .


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  • richardmitnick 5:37 pm on January 8, 2018 Permalink | Reply
    Tags: , , , PHENIX, , RHIC,   

    From BNL: “Surprising Result Shocks Scientists Studying Spin” 

    Brookhaven Lab

    January 8, 2018
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

    Peter Genzer,
    genzer@bnl.gov
    (631) 344-3174

    Findings on how differently sized nuclei respond to spin offer new insight into mechanisms affecting particle production in proton-ion collisions at the Relativistic Heavy Ion Collider (RHIC).

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    1
    The PHENIX detector at the Relativistic Heavy Ion Collider (RHIC).


    Alexander Bazilevsky discusses surprising particle spin results from the Relativistic Heavy Ion Collider at Brookhaven National Laboratory.

    Imagine playing a game of billiards, putting a bit of counter-clockwise spin on the cue ball and watching it deflect to the right as it strikes its target ball. With luck, or skill, the target ball sinks into the corner pocket while the rightward-deflected cue ball narrowly misses a side-pocket scratch. Now imagine your counter-clockwise spinning cue ball striking a bowling ball instead, and deflecting even more strongly—but to the left—when it strikes the larger mass.

    That’s similar to the shocking situation scientists found themselves in when analyzing results of spinning protons striking different sized atomic nuclei at the Relativistic Heavy Ion Collider (RHIC)—a U.S. Department of Energy (DOE) Office of Science User Facility for nuclear physics research at DOE’s Brookhaven National Laboratory. Neutrons produced when a spinning proton collides with another proton come out with a slight rightward-skew preference. But when the spinning proton collides with a much larger gold nucleus, the neutrons’ directional preference becomes larger and switches to the left.

    2
    Brookhaven Lab physicist Alexander Bazilevsky and RIKEN physicist Itaru Nakagawa use billiards and a bowling ball to demonstrate surprising results observed at the Relativistic Heavy Ion Collider’s PHENIX detector when small particles collided with larger ones.

    “What we observed was totally amazing,” said Brookhaven physicist Alexander Bazilevsky, a deputy spokesperson for the PHENIX collaboration at RHIC, which is reporting these results in a new paper just published in Physical Review Letters. “Our findings may mean that the mechanisms producing particles along the direction in which the spinning proton is traveling may be very different in proton-proton collisions compared with proton-nucleus collisions.”

    Understanding different particle production mechanisms could have big implications for interpreting other high-energy particle collisions, including the interactions of ultra-high-energy cosmic rays with particles in the Earth’s atmosphere, Bazilevsky said.

    Detecting particles’ directional preferences

    Spin physicists first observed the tendency of more neutrons to emerge slightly to the right in proton-proton interactions in 2001-2002, during RHIC’s first polarized proton experiments. RHIC, which has been operating since 2000, is the only collider in the world with the ability to precisely control the polarization, or spin direction, of colliding protons, so this was new territory at the time. It took some time for theoretical physicists to explain the result. But the theory they developed, published in 2011, gave scientists no reason to expect such a strong directional preference when protons were colliding with larger nuclei, let alone a complete flip in the direction of that preference.

    3
    Neutrons produced when a spin-aligned (polarized) proton collides with another proton come out with a slight rightward-skew preference. But when the polarized proton collides with a much larger gold nucleus, the neutrons’ directional preference becomes larger and switches to the left. These surprising results imply that the mechanisms producing particles along the beam direction may be very different in these two types of collisions.

    “We anticipated something similar to the proton-proton effect, because we couldn’t think of any reasons why the asymmetry could be different,” said Itaru Nakagawa, a physicist from Japan’s RIKEN laboratory, who served as PHENIX’s deputy run coordinator for spin measurements in 2015. “Can you imagine why a bowling ball would scatter a cue ball in the opposite direction compared with a target billiard ball?”

    2015 was the year RHIC first collided polarized protons with gold nuclei at high energy, the first such collisions anywhere in the world. Minjung Kim—a graduate student at Seoul National University and the RIKEN-BNL Research Center at Brookhaven Lab—first noticed the surprisingly dramatic skew of the neutrons—and the fact that the directional preference was opposite to that seen in proton-proton collisions. Bazilevsky worked with her on data analysis and detector simulations to confirm the effect and make sure it was not an artifact from the detector or something to do with the adjustment of the beams. Then, Nakagawa worked closely with the accelerator physicists on a series of experiments to repeat the measurements under even more precisely controlled conditions.

    “This was truly a collaborative effort between experimentalists and accelerator physicists who could tune such a huge and complicated accelerator facility on the fly to meet our experimental needs,” Bazilevsky said, expressing gratitude for those efforts and admiration for the versatility and flexibility of RHIC.

    The new measurements, which also included results from collisions of protons with intermediate-sized aluminum ions, showed the effect was real and that it changed with the size of the nucleus.

    “So we have three sets of data—colliding polarized protons with protons, aluminum, and gold,” Bazilevsky said. “The asymmetry gradually increases from negative in proton-proton—with more neutrons scattering to the right—to nearly zero asymmetry in proton-aluminum, to a large positive asymmetry in proton-gold collisions—with many more scatterings to the left.”

    Particle production mechanisms

    To understand the findings, the scientists had to look more closely at the processes and forces affecting the scattering particles.

    “In the particle world, things are much more complicated than the simple case of (spinning) billiard balls colliding,” Bazilevsky said. “There are a number of different processes involved in particle scattering, and these processes themselves can interact or interfere with one another.”

    “The measured asymmetry is the sum of these interactions or interferences of different processes,” said Kim.

    Nakagawa, who led the theoretical interpretation of the experimental data, elaborated on the different mechanisms.

    The basic idea is that, in the case of large nuclei such as gold, which have a very large positive electric charge, electromagnetic interactions play a much more important role in particle production than they do in the case when two small, equally charged protons collide.

    “In the collisions of protons with protons, the effect of electric charge is negligibly small,” Nakagawa said. In that case, the asymmetry is driven by interactions governed by the strong nuclear force—as the theory developed back in 2011 correctly described. But as the size, and therefore charge, of the nucleus increases, the electromagnetic force takes on a larger role and, at a certain point, flips the directional preference for neutron production.

    The scientists will continue to analyze the 2015 data in different ways to see how the effect depends on other variables, such as the momentum of the particles in various directions. They’ll also look at how preferences of particles other than neutrons are affected, and work with theorists to better understand their results.

    Another idea would be to execute a new series of experiments colliding polarized protons with other kinds of nuclei not yet measured.

    “If we observe exactly the asymmetry we predict based on the electromagnetic interaction, then this becomes very strong evidence to support our hypothesis,” Nakagawa said.

    In addition to providing a unique way to understand different particle production mechanisms, this new result adds to the puzzling story of what causes the transverse spin asymmetry in the first place—an open question for physicists since the 1970s. These and other results from RHIC’s polarized proton collisions will eventually contribute to solving this question.

    This work was supported by the DOE Office of Science, and by all the agencies and organizations supporting research at PHENIX.

    See the full article here .

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  • richardmitnick 9:33 am on June 17, 2016 Permalink | Reply
    Tags: , , Particle colliders, RHIC,   

    From BNL: “Calorimeter Components Put to the Test” 

    Brookhaven Lab

    June 15, 2016
    Karen McNulty Walsh
    kmcnulty@bnl.gov

    Brookhaven scientists, students, and university partners help build and test key components for a possible future RHIC detector upgrade

    1
    Brookhaven Lab physicist Martin Purschke with sPHENIX calorimeter components at the Fermilab Test Beam Facility (Photo credit: Fermilab)

    Tracking particles created in subatomic smashups takes precision. So before the components that make up detectors at colliders like the Relativistic Heavy Ion Collider (RHIC) get the chance to see a single collision, physicists want to be sure they are up to the task.

    BNL RHIC CampusBNL RHIC
    BNL/RHIC map; RHIC collider

    A group of physicists and students hoping to one day build a new detector at RHIC—a DOE Office of Science User Facility for nuclear physics research at the U.S. Department of Energy’s Brookhaven National Laboratory—recently spent time at DOE’s Fermi National Accelerator Laboratory putting key particle-tracking components to the test.

    “We want to do full jet reconstruction,” said physicist Megan Connors, a member of the new sPHENIX collaboration building and testing components for a proposed upgrade to RHIC’s PHENIX detector designed to transform it into a new state-of-the-art experiment.

    BNL/RHIC PhenixBrookhaven Phenix
    BNL/RHIC Phenix

    Connors spent time tracking “jets” as a graduate student and postdoc at RHIC and the Large Hadron Collider. Now a RIKEN-BNL Research Center Fellow who will begin teaching at Georgia State University next year, Connors says a new high-energy jet detector would offer the best opportunity to see deep into the hot particle soup created in RHIC’s most energetic smashups. By adding up the energy of the sprays of particles emitted when high-energy quarks and gluons traverse the quark-gluon plasma, physicists hope to understand how its remarkable properties emerge from the individual quark and gluon interactions.

    The device that measures the energy of these jet particle sprays is called a calorimeter. To do a good job, it must completely surround the collision zone and be thick enough to catch all the particles.

    Anne Sickles, a physicist at the University of Illinois at Urbana-Champaign, has been working with her students and a company in San Diego to build electron- and light-sensing bricks for the inner layer, the “electromagnetic” calorimeter.

    They start with a tungsten powder that looks like black sand, placing fibers that look like straws into the powder. “Then we draw epoxy through it all to end up with bricks that have scintillating fibers running through them,” she explained.

    “When a photon—a particle of light—hits these bricks, it starts to interact with the tungsten, and those interactions produce more photons and more interactions, like a chain reaction. Ultimately you get a shower with lots of light that travels down the length of the scintillating fibers to a silicon photomultiplier—a photo detector that changes the light to electric signals we read out. We use all this information to measure how much energy was in the initial photon.”

    2
    Megan Connors, a RIKEN-BNL Research Center Fellow and member of sPHENIX, holds an electronic readout from the hadronic calorimeter the team is designing for the detector upgrade.

    Getting that measurement right is crucial, Sickles explained, because when a photon is emitted from a particle collision back-to-back with a jet, it tells you how much energy the jet started with. The next step is determining how much energy the jet loses in its interactions with the quark-gluon plasma by measuring and adding up the energy of all the jet particles moving in the opposite direction.

    Photons and electrons would deposit all of their energy in the electromagnetic calorimeter. Heavier particles made of quarks, known as hadrons, deposit some energy in the electromagnetic calorimeter. But in many cases, they continue to fly right through. To stop them and measure their full energy, you need a hadronic calorimeter—the detector component Connors has been working on.

    “The hadronic calorimeter is made of two independent parts—the inner and outer hadronic calorimeters—which will be located just inside and outside the sPHENIX magnet,” Connors said. “They consist of alternating layers of steel plates and angled scintillator tiles.

    “When particles hit the steel they lose energy and produce secondary particles, which ‘excite’ the tiles and make them emit light. A light-sensing fiber running through each tile collects the light so it can be read out by a silicon photomultiplier, just as is done for the electromagnetic calorimeter,” she explained.

    4
    sPHENIX member Anne Sickles, left, with some of her students at the University of Illinois at Urbana-Champaign who helped to build components for a prototype electromagnetic detector: postdoctoral fellow Vera Loggins, graduate student Mike Phipps, and undergraduates Simon Li and Michael Higdon (Photo credit: University of Illinois)

    The Test Beam Facility at Fermilab [FNAL] is the perfect place to put these components through their paces.

    FNAL Test Beam Facility
    FNAL Test Beam Facility

    Sickles was heavily involved in the first round of tests. She and her team built a prototype of the full electromagnetic calorimeter using 32 bricks, each made of two one-by-one-inch tungsten towers. Working with Brookhaven physicists who had connected these components to the electronic readouts, they placed an 8” by 8” grid of bricks into the path of a beam of electrons.

    Photons and electrons will both interact with the calorimeter in the same way and sPHENIX will use its capabilities to measure both kinds of particles. By tracking electrons, the sPHENIX electromagnetic calorimeter would also help physicists trace the interactions of “upsilon” particles with the quark-gluon plasma.

    “We use electron beams at various energies,” Sickles explained. “Since we know what energy goes in and we measure what comes out, and the width of the distribution in energies, we can determine how good the resolution of the detector is. We are looking for a narrow peak—a tight correlation between what we put in and what we measure.”

    5
    A closeup of the scintillating fibers traversing one of the tungsten bricks designed to track electrons and photons in the sPHENIX electromagnetic calorimeter. (Photo credit: Anne Sickles)

    They also took measurements to compare the response of bricks built by Sickles and postdoc Vera Loggins and several students at the University of Illinois with those built by Tungsten Heavy Powder, the company in San Diego. “The plan for the actual sPHENIX detector is to have 25,000 tungsten towers,” Sickles said, “so we have to be sure they all have the same level of performance.”

    Similar to the way the electromagnetic calorimeter was tested using an electron beam, the energy-resolution capabilities of the hadronic calorimeter were tested using a hadron beam of known energy. First the scientists did standalone tests to measure the hadronic calorimeters’ performance alone. Following those studies, members of the sPHENIX team placed the prototype hadronic calorimeter components directly behind the electromagnetic mockup to study how the two detector layers would ultimately work together.

    “The tests of the hadronic calorimeter with the electromagnetic calorimeter in front of it measure the performance we would expect to see in sPHENIX,” Connors said. “We also placed metal in between the inner and outer hadronic calorimeters to simulate the material of the magnet.

    6
    Additional members of the team involved in testing sPHENIX calorimeter components at the Test Beam Facility at Fermilab: Brookhaven Lab physicists Jin Huang and Martin Purschke; Ron Belmont, University of Colorado, Boulder; and Brookhaven physicists John Haggerty and Craig Woody. (Photo credit: Fermilab)

    “It’s really coming to life,” said Connors, who has been analyzing the data from the prototype testing. “It’s great to be able to access the data from these tests remotely so people all over the world can be involved if they want.

    “We will take what we learn about how well the detector will perform based on the testing at Fermilab, and then use that knowledge to finalize the design,” she said.

    The electromagnetic and hadronic calorimeter prototypes were assembled at Brookhaven Lab by technicians Carter Biggs, Sal Polizzo, Mike Lenz, and Frank Toldo under the direction of Brookhaven physicists John Haggerty, Jin Huang, Edward Kistenev, Eric Mannel, and Craig Woody, and physics associate Sean Stoll. The prototypes, designed and engineered by Richie Ruggiero, incorporated electronics designed by Steve Boose and data acquisition software provided by Martin Purschke. John Lajoie and Abhisek Sen of Iowa State University and Ron Belmont from the University of Colorado worked closely with the Brookhaven team on the hadronic calorimeter construction and analysis. Mandy Rominsky and Todd Nebel of the Fermilab Test Beam Facility were also instrumental in the success of the tests.

    sPHENIX R&D is supported by the DOE Office of Science and also by Brookhaven Lab’s Laboratory Directed Research and Development program, BNL Program Development, and in-kind contributions from collaborating universities.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition
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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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