A Simulation Study on Tune Modulation Effects in RHIC

Ficsher, W; Satogata, T.

doi:10.2172/1119502

Cited by 4 publications

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“…The effect of tune modulation on the dynamic aperture has been studied with experiments and simulations for the Tevatron [3,4], SPS [5], HERA [6][7][8], RHIC [9] and the LHC [10,11]. A detrimental effect of tune modulation on the dynamic aperture and lifetime was found even with tune modulation depth well below 10 −3 .…”

Section: Tune Modulation Parametersmentioning

confidence: 99%

Tune Modulation from Beam-Beam Interaction and Unequal Radio Frequency in RHIC

Fischer¹,

Cameron²,

Peggs³

et al. 2002

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The two RHIC rings have independent rf systems to accommodate different species. Thus, the radio frequencies can differ when the phase and radial loops are closed, and the rf frequencies of the two rings are not synchronized. A radio frequency difference leads to longitudinally moving beam crossing points. When the crossing points are between the beam splitting dipoles, the beams experience the beam-beam interaction. Outside the interaction region the beam-beam interaction is switched off. In this way the tune is modulated. A computation of the tune modulation depth, pulse shape and frequency is presented. Tune modulation measurements are shown.

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Section: Tune Modulation Parametersmentioning

confidence: 99%

Tune Modulation from Beam-Beam Interaction and Unequal Radio Frequency in RHIC

Fischer¹,

Cameron²,

Peggs³

et al. 2002

Self Cite

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“…A linear correlation between the DA reduction and the synchrotron or gradient modulation depth was identified. By including in the simulations the voltage tones obtained from experimental observations, in combination with a modulation depth of 10 −3 from synchrobetatron coupling, a DA reduction was observed for a variation of 10 −5 in the quadrupolar current [18]. In the Hadron-Electron Ring Accelerator (HERA) at DESY, a threshold of 10 −4 in the modulation depth was defined from analytical derivations in the presence of both beambeam effects and a high-frequency tune modulation, a limit which was also verified experimentally by injecting external noise [19].…”

Section: Introductionmentioning

confidence: 99%

Tune modulation effects in the High Luminosity Large Hadron Collider

Kostoglou,

Bartosik,

Papaphilippou

et al. 2020

Preprint

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Several transverse noise sources, such as power supply ripples, can potentially act as an important limiting mechanism for the luminosity production of the Large Hadron Collider (LHC) and its future High-Luminosity upgrade (HL-LHC). In the presence of non-linearities, depending on the spectral components of the power supply noise and the nature of the source, such a mechanism can increase the diffusion of the particles in the distribution through the excitation of sideband resonances in the vicinity of the resonances driven by the lattice non-linearities. For the HL-LHC, due to the reduction of the beam size in the Interaction Points (IP) of the high luminosity experiments (IP1 and 5), increased sensitivity to noise effects is anticipated for the quadrupoles of the inner triplets. The modulation that may arise from the power supply ripples will be combined with the tune modulation that intrinsically emerges from the coupling of the transverse and longitudinal plane for off-momentum particles through chromaticity. To this end, the aim of this paper is to study the impact of tune modulation effects on the transverse beam motion resulting from the interplay between quadrupolar power supply ripples and synchro-betatron coupling. A power supply noise threshold for acceptable performance is estimated with single-particle tracking simulations by investigating the impact of different modulation frequencies and amplitudes on the Dynamic Aperture. The excitation of sideband resonances due to the modulation is demonstrated with frequency maps and the higher sensitivity to specific modulation frequencies is explained. Finally, a power supply noise spectrum consisting of several tones is considered in the simulations to determine whether the presence of power supply ripples in the quadrupoles of the inner triplet will limit the luminosity production in the HL-LHC era.

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“…to simulate the collimators and particles with actions beyond this threshold are considered lost. Observations of harmonics of the mains power frequency in the beam spectrum with a dipolar nature have been reported in the past from several accelerators such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) [75,76], the Tevatron in Fermi National Accelerator Laboratory (FNAL) [31,32] and SPS at CERN [28,77]. In particular, the study conducted at RHIC demonstrated that high order harmonics (h>100) were visible in several unrelated instruments, as a result of a real beam excitation, rather than an artifact of the instrumentation system.…”

Section: Weighted Distributionsmentioning

confidence: 99%

“…A linear correlation between the DA reduction and the synchrotron or gradient modulation depth was identied [111,112]. By including in the simulations the voltage tones obtained from experimental observations, in combination with a modulation depth of 10 −3 from synchro-betatron coupling, a DA reduction was observed for a variation of 10 −5 in the quadrupolar current [76]. Furthermore, a tune modulation was also observed due to the dierence in the Radio Frequencies (RF) of the two beams that led to a variation of the beam crossing location in the Interaction Region (IR), an eect that was not present once the RF were synchronized [75].…”

Section: Introductionmentioning

confidence: 98%

Noise effects in the large hadron collider (LHC) and its high-luminosity upgrade (HL-LHC)

Kostoglou¹,

Κώστογλου²

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Ο Μεγάλος Επιταχυντής Αδρονίων ολοκλήρωσε με επιτυχία το δεύτερο κύκλο λειτουργίας του έπειτα από τρία χρόνια πειραμάτων (2015-2018), επιτυγχάνοντας πρωτοφανείς τιμές ολοκληρωμένης φωτεινότητας και ενέργειας κέντρου μάζας. Για τα επόμενα δύο χρόνια προβλέπονται εκτεταμένες τροποποιήσεις με σκοπό την προετοιμασία του επιταχυντή για τη μελλοντική του αναβάθμιση σε επιταχυντή Υψηλής Φωτεινότητας. Η βελτιστοποίηση της απόδοσης του επιταχυντή απαιτεί, παράλληλα, την κατανόηση όλων των μηχανισμών που μπορούν να συντελέσουν στη μείωση ή υποβάθμιση της τιμής της φωτεινότητας. Ένας μηχανισμός που μπορεί να επηρεάσει την εγκάρσια κίνηση των σωματιδίων της δέσμης πρωτονίων, οδηγώντας σε χαοτικές τροχιές και κατ' επέκταση σε απώλειες πρωτονίων, είναι τα φαινόμενα θορύβου στη δυναμική των φορτισμένων σωματιδίων. Ανάμεσα στις πολλαπλές πηγές θορύβου που υπάρχουν σε έναν επιταχυντή, η παρούσα διδακτορική διατριβή επικεντρώνεται στις επιπτώσεις αρμονικών διαταραχών στην τάση των πηγών τροφοδοσίας των μαγνητικών διπόλων και τετραπόλων, ένα φαινόμενο που οδηγεί σε διαμόρφωση συχνότητας του μαγνητικού πεδίου. Ανάλογα με τις συχνότητες και το πλάτος των φασματικών συνιστωσών του θορύβου, που εξαρτώνται από το είδος του μαγνήτη και τον τύπο της πηγής τροφοδοσίας, οι επιπτώσεις στην εγκάρσια κίνηση των σωματιδίων της δέσμης ποικίλουν. Ο θόρυβος από τις πηγές τροφοδοσίας, σε συνδυασμό με τα μη-γραμμικά μαγνητικά πεδία του επιταχυντή, που είτε είναι απαραίτητα για τον έλεγχο της χρωματικότητας και την απόσβεση της συλλογικής κίνησης των σωματιδίων είτε απορρέουν από τη σύγκρουση των δύο δεσμών, μπορεί να αυξήσει τη διάχυση της κατανομής των σωματιδίων, μέσω της εμφάνισης και διέγερσης των επιπλέον συχνοτήτων συντονισμού πέρα από τις προβλεπόμενες λόγω της μη-γραμμικότητας των επί μέρους μαγνητικών πεδίων. Η ύπαρξη ενός τέτοιου φαινομένου είναι ιδιαιτέρως κρίσιμη για τη διατήρηση του συνολικού χρόνου ζωής της δέσμης. Η παρούσα έρευνα παρουσιάζει τη μελέτη αυτών των φαινομένων πρώτα στα δίπολα, ένα φαινόμενα που έχει παρατηρηθεί στον επιταχυντή, και στη συνέχεια στα τετράπολα, ένα είδος θορύβου που είναι ιδιαίτερα κρίσιμο για τον επιταχυντή Υψηλής Φωτεινότητας.

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A Simulation Study on Tune Modulation Effects in RHIC

Cited by 4 publications

References 0 publications

Tune Modulation from Beam-Beam Interaction and Unequal Radio Frequency in RHIC

Tune Modulation from Beam-Beam Interaction and Unequal Radio Frequency in RHIC

Tune modulation effects in the High Luminosity Large Hadron Collider

Noise effects in the large hadron collider (LHC) and its high-luminosity upgrade (HL-LHC)

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