DAΦNE as Open Accelerator Test Facility - CERN Indico

DAFNE as Open Accelerator Test FacilityCatia MilardiCEPC-Workshop – 15÷17 Apr 2019 – Oxford, UK.

Workshop on the Circular Electron-Positron Collider, EU Editition 2019, 15 – 17 April 2019, Oxford, UK.

Catia MilardiScientific Head of the DAFNE Accelerator Complex

DAFNE as Open Accelerator Test Facilityaimed at studying Physics and Innovative Technologies for Particle Accelerators


Outline

• DAFNE overview

• DAFNE achievements and contributions to the physics of particle accelerators

• The opportunity of converting the accelerator complex into a Test Facility

• Some ideas from the DAFNE-TF workshop

• Conclusions


BTF

X-ray 900 - 3000 eV

IR 1.24 meV - 1.24 eV

UV 2 - 10 eV

The DAFNE Accelerator Complex

LNF are also part of the European synchrotron light Infrastructures

e+ e-

C ≈ 97 mECM = 1.02 GeV (F)

FINUDAFrascati National Laboratories (LNF)


• DAFNE is an electron-positron collider designed in the mid ‘90s, it came into operation in 2000

• It has been providing data in consecutive data-taking periods to:KLOE, DEAR and FINUDA experiments until 2007SIDDHARTA in 2008 � 2009again for the upgraded KLOE-2 between November 2014 and March 2018

• Present DAFNE activitiesas a collider for the SIDDHARTA-2 experimentDAFNE-light Facility DAFNE LINAC is securing data to the PADME experiment and to two BTF lines

DAFNE History & Plans

By the end of 2020 DAFNE will stop running as a collider and will be most likely transformed in a open accelerator test facility.


• DAFNE is an electron-positron collider designed in the mid ‘90s, it came into operation in 2000

• It has been providing data in consecutive data-taking periods to:KLOE, DEAR and FINUDA experiments until 2007SIDDHARTA in 2008 � 2009again for the upgraded KLOE-2 between November 2014 and March 2018

• Present DAFNE activitiesas a collider for the SIDDHARTA-2 experimentDAFNE-light Facility DAFNE LINAC is securing data to the PADME experiment and to two BTF lines

DAFNE History & Plans

By the end of 2020 DAFNE will stop running as a collider and will be most likely transformed in a open accelerator test facility.

Crab-Waist Collisions


Luminosity Achievements (native configuration)DAFNEnative

Energy (MeV) 510

qcross/2 (mrad) 12.5

ex (mm•mrad) 0.34

bx* (cm) 160

sx* (mm) 0.70

FPiwinski 0.6

by* (cm) 1.80

sy* (µm) low current 5.4

Coupling, % 0.5

Bunch spacing (ns) 2.7

Ibunch (mA) 13

sz (mm) 25

Nh 120

FINUDA (DEAR)

KLOE

“Proposal for a F-factory”, G. Vignola et al., LNF-90/031 (IR),1990.

KLOE 3.0FINUDA 1.2DEAR 0.2

Llogged (fb-1) 2001�2007


Crab-Waist Collision Test Run

DAFNEnative

DAFNE Crab-Waist

Energy (MeV) 510 510

qcross/2 (mrad) 12.5 25

ex (mm•mrad) 0.34 0.28

bx* (cm) 160 23

sx* (mm) 0.70 0.25

FPiwinski 0.6 1.5

by* (cm) 1.80 0.85

sy* (µm) low current 5.4 3.1

Coupling, % 0.5 0.5

Bunch spacing (ns) 2.7 2.7

Ibunch (mA) 13 13

sz (mm) 25 15

Nh 120 120

DAFNE Crab-Waist

SIDDHARTA

P. Raimondi , 2� SuperB Workshop, March 2006,P.Raimondi, D.Shatilov, M.Zobov, physics/0702033,C. Milardi et al., Int.J.Mod.Phys.A24, 2009.

Tested with the SIDDHARTA detector in 2008�2009

• Large Piwinski angle and Crab-Waist scheme provided:optimal control of the beam-beam interactiona factor 3 higher Lpeak

complete elimination of the LRBB

Lpeak = 4.5*1032 cm-2 s-1

L∫1 day = 15.0 pb-1

L∫1 hour = 1.033 pb-1 (test run)

L∫run ~ 2.8 fb-1 (logged by the experiment)M. Zobov et al., Phys.Rev.Lett.104:174801, 2010.


Crab-Waist Collision with KLOE-2

C. Milardi et al 2012 JINST 7 T03002.

Crab-Waist collision scheme implemented for the first time with a large detector including a high intensity axial field

The new approach to collision provided a ~60% improvement in terms of Lpeak


DAFNE CW upgrade

tested with SIDDHARTA (2009)

DAFNEKLOE (2005)

DAFNE (CW)KLOE-2 (2014)

Lpeak [cm-2s-1] 4.53•1032 1.50•1032 2.38•1032

I- [A] 1.52 1.4 1.18

I+ [A] 1.0 1.2 0.87

ex [mm mrad] 0.28 0.34 0.28

Nbunches 105 111 106

∫1h L [pb-1] 0.79 0.4 0.67

∫dayL [pb-1] 14.98 9.8 (seldom) 14.3

xy 0.0443 - 0.074* 0.0245 --

DAFNE Luminosity AchievementsLuminosity achieved at DAFNE is almost an order of magnitude higher than the one obtained at other colliders operating in the low energy range


Collider Location StatusDAFNE F-Factory

Frascati, ItalyIn operation

SuperKEKB B-FactoryTsukuba, Japan

Under commissioning

SuperC-Tau C-Tau-FactoryNovosibirsk, Russia

Russian mega-science project

FCC-eeHiggs-Factory

CERN,Switzerland100 km, CW baseline

design option

CEPC Higgs-FactoryChina

54 km, local double ring option with CW

LHC Upgrade LHC CW OptionCERN,Switzerland

LHC with very flatbeams (low priority)

Crab-Waist CollidersNew machines and projects around the world have adopted the Crab-Waist collision scheme as their main design concept


D. Alesini, Boni, A. Drago, A. Gallo, A. Ghigo, M. Serio, A Stella, M. Zobov, F. Marcellini, P. Raimondi

DAΦNE Vacuum Chamber ElementsOptimized to: avoid heating, reduce impedance, and damp HOM

Impedance budget is a factor of 80 lower than in similar storage ring (EPA)

Longitudinal feedback kicker designed for DAFNE have been adopted at: KEKB, BESSYII, PLS, SLS, HLS, ELETTRA, KEK Photon Factory, PEP II

This R&D effort largely contributed to improve beam dynamics and beam-beam performances


Beam Currents stored at DAFNE Lepton Beam Currents achieved so far

beam current I [A]

bunch populationNb [1011]

rms bunch length [mm]

bunch spacing [ns]

comment

PEP-II 2.1 (e-), 3.2 (e+) 0.5, 0.9 12 4.2 closedsuperKEKB 2.62 (e-), 3.6 (e+) 0.7, 0.5 7 6 commissioning

DAFNE 2.4 (e-), 1.4 (e+) 0.4, 0.3 16 2.7BEPC-II 0.8 0.4 <15? 8CesrTA 0.2 0.2 6.8 4VEPP-2000 0.2 1 33 80 (1 b)LHC (des) 0.58 1.15 75.5 25ESRF 0.2 0.04 6.0 2.8APS 0.1 0.02 6.0 2.8Spring8 0.1 0.01 4.0 2.0SLS 0.4 0.05 9.0 2.0


R&D about e-cloud suppression at DAFNE

(D. Alesini et al, Phys. Rev. Lett. 110, 124801 (2013)

Horizontal Instability Growth Rate as a

function of the ECE voltage measured by using bunch-by-bunch FBK frontend

Dnx1-100 ~ 0.006 (off)

Dnx1-100 ~ 0.003 (on)

<Dnx > ~ 0.0065 (on/off)

Dny1-10 ~ 0.002 (on/off)

Tune Spread measurements

Vertical Beam Sizesy (µm)

DAΦNE is the first collider operating routinely with electrodes, for e-cloud mitigation, ECE.ECE provided stable operation with the e+ beam, and allowed unique measurements such as:

e-cloud instabilities growth ratetransverse beam size variationtune shifts along the bunch train

demonstrating their effectiveness in restraining e-cloud induced effects.


Feedback R&D and Instability Cures at DAFNE High current performances in a low energy machine greatly depend on bunch by bunch feedback systems.DAFNE performances are assured by the 3 feedbacks installed in each ring in order to dampen coupled-bunch instabilities both in the longitudinal and transverse plane

DAFNE FBKs are based on iGp (Integrated Gigasample Processor) digital bunch-by-bunch hardware developed by a KEK / SLAC / INFN-LNF joint collaboration.

The total power available for each apparatus is of the order of 500 W and 750 W for transverse and longitudinal feedbacks respectively

Transverse FBKs have been equipped with in house developed new kickers having doubled strip-line length and providing larger shunt impedance at the low frequencies typical of the unstable modes.

Beam current limits observed• longitudinal mode-0 & quadrupole oscillations• noise coming from pickups (harmful for beam vertical size)• e-cloud effects (in the e+ ring)

Solutions:• Longitudinal quadrupole control by a special technique implemented at

DAFNE in the dipole feedback system• Transverse low noise front end (in collaboration with KEK)


Revolution harmonic Synchrotron (dipole) oscillations damped by Long FBK

(A.Drago, et al., PRST-AB, 6, 052801-1-11, 2003)

This instability, if not controlled, saturates the longitudinal feedback

@ f ~ 2 • fsync

Longitudinal Quadrupole Oscillations

Quadrupole oscillation


ac < 0 at DAΦNEExperimental Results

• DAΦNE flexible optics

-0.036 ≤ ac ≤ +0.034

• Bunches shorten as predicted by numerical simulations.

• It was possible to store high bunch currentwith large negative chromaticity

Ib ~40 mA

• Stable multibunch beams with I > 1 A

• Specific luminosity gain of about 25% till 300 mA per beam without SXTs

• Higher current beam-beam collisions faileddue to sy

- above the microwave instabilitythreshold

Collisions with ac < 0 have never been tested elsewhere


Other contributions to particle accelerator physics

Ideas and studies aimed at improving beam dynamics and beam-beam performances:

• short pulse PS for injection kickers

• non-linearities mitigation in magnet fields especially in wigglers

• parasitic crossing compensation by current carrying wires• collisions with very high crossing angle

• strong RF focusing

Proposals:• DANAE (1.02 GeV� 2.4 GeV)

• Bunch lenght modulation experiment

• DAFNE-VE (0.6 GeV� 3 GeV with CW)


The previous considerations, and not just those, led to conclude that DAFNE is a unique facility to realize tests and measurements finalized to:

• study physics problems and innovative technologies which are of interest for the particle accelerator community

• test innovative concepts

• implement short term experiment about fundamental and applied physics

• train young generations of particle accelerator physicists

That said ….


It is the only existing phi-factory and, until the entry into operation of SuperKEKB, it will be the only collider on which the Crab-Waist Collision scheme has been successfully implemented with and without the experiment solenoid.

If converted into a facility for the study of physics and technologies for accelerators, DAFNE-TF would add to the small number of accelerators available for this purpose. If one considers just electron machines, this list includes ATF2 (KEK), a top-class facility designed for the development of the International Linear Collider, CLASSE (Cornell Laboratory for Accelerator Based Science and Education), a centre of excellence in the development of accelerator technologies located in an university campus, and KARA (Karlsruhe), devoted to R&D of machines and applied research.

The Opportunity of DAFNE-TF


The DAFNE-TF Opportunity

DAFNE-TF would be the only facility in Europe to provide a positron beam.

DAFNE-TF would operate when CERN won’t have beams• over 2019-20, due to the realization of the upgrade of

LHC injectors• during each of the long stops LS3 (2024, HL-LHC

installation) and LS4 (2030)

In this context the availability of DAFNE-TF for accelerator studies will be even more interesting.


The lines of scientific and technological research should meet some basic conditions:

• Compliance with the machine operating parameters

• Limited impact in terms of machine layout and componentsmodification, invasive measurements and experimental activitieshardly compatible with the actual machine configuration are unlikelyto be considered

•maturity level of the experimental programmes proposed.

DAFNE-TF Operation Framework


•Much of the hardware installed in DAFNE, although constantly maintained and improved, dates from the mid '90s.•A major refurbishment (for an amount of about 1000 K€) was realized in 2013, and continued

in the following years.•A significant upgrade of the LINAC is under way, including the split of the Beam Test Facility

(BTF) in order to increase the number of future users.• The PSs, of the steering magnets (short and long type) both in the positrons and in the

electrons rings have been substituted by new equipment. The new PSs have accuracy and resolution improved by more than a factor 10 with respect to the old devices.

•Despite the relatively obsolete nature of part of its components, DAFNE and BTF are able to regularly provide beams for more than 6,000 hours per year, keeping their operational efficiency at levels of the orders of 80% for long periods.

• In the same years, the synchrotron-light laboratory has profited from the e- beam radiation in parasitic mode, hosting external users for about 800 hours per year, and getting the CALYPSO program of Horizon 2020. The synchrotron-light activity allowed the Laboratory to be included into LEAPS, League of European Accelerator-based Photon Sources

• The DAFNE complex also hosts a cryogenic plant, recently refurbished, which can be efficiently used to operate superconducting magnets, experimental setups, and superconducting radiofrequency systems (although the latter ones have never been used at DAFNE).

About the DAFNE Infrastructure


• Study of low SEY (Secondary Electron Yield) elements and impedances;Graphitization of chambers and other technologies.

• Accelerator components realized with 3D printers.

• High gradient tuneable permanent magnets

• High power solid state RF amplifiers

• High-power positron sources: peak Energy Deposition Density in the targets,wide aperture capture, accelerating sections in S Band

Possible activities


• Components for future SLED and pulse flatness compensation

• Components for accelerators (vacuum chambers, collimators, masks,kickers) and innovative beam diagnostic techniques

• Emittance manipulation

• Beams interacting with amorphous materials, crystals, lasers, plasma

Possible activities


DAFNE-TF might also host small-size experiments in the field of fundamental and applied physics requiring a small-size data sample.The qualifying element of every possible proposal in this field is the time scale.

Among the possible proposals there are the measurement of processes with high effective cross sections, which are feasible with small experimental set-ups such as study of interactions K0

L or K charged with specific materials or small-angle scattering, where interesting possibilities of testing small-angle detection systems in vacuum exist, e.g. with Roman Pot detectors highly demanding in terms of spatial and temporal resolution, high rate, radiation resistance, etc ....

Possible activities


DAΦNE-TF might represent an excellent training tool for physicists, technologists and technicians with skills in accelerators and related technologies, in particular in the field of lepton machines, in which LNF has always played a leading role, internationally acknowledged.

Training Opportunity

https://agenda.infn.it/event/16334/images/2335-DAFNE2020_EN.pdf

https://agenda.infn.it/event/16334/images/2335-DAFNE2020_EN.pdf


DAFNE Frascati

Physics start date 1999Physics end date ---Maximum beam energy (GeV) 0.510Luminosity (1030 cm−2 s−1 ) 453Time between collisions (μs) 0.00271. Full crossing angle (μ rad) 5.*104

Energy spread (units 10−3) 0.40Bunch length (cm) 1.4 (at 10 mA)

Beam radius (μ)H: 260 (at IP)

V: 4.8Free space at interaction point (m) ±0.295Luminosity lifetime (h) 0.2Maximum achieved current e-/e+ (A) 2.45 / 1.4Turn-around time (min) 2 ( topping up)Injection energy (GeV) on energy

Transverse emittance (10−9 π rad-m)H: 260V: 2.6

β* amplitude function at interaction point (m)H: 0.26V: 0.009

Beam-beam tune shift per crossing (units 10−4) 440 (at LMAX SIDDHARTA run)RF frequency (MHz) 368.667Particles per bunch (units 1010 ) e-: 3.2 / e+: 2.1Bunches per ring per species 100 ÷ 105 (120 buckets)

Average beam current per species (mA)e-: 1500e+: 1000

Circumference (km) 0.098Interaction regions 1 (a second one can be restored)

Magnetic length of dipole (m)Outer ring: 1.2

Inner ring: 1Length of standard cell (m) No standard cellPhase advance per cell (deg) ---Dipoles in each ring 8Quadrupoles in each ring 48Peak magnetic field in dipoles (T) 1.2Wigglers in each ring 4Damping Times (tE/tx), ms 17.8 / 36.0

The DAFNE Parameter List


DAFNE-TF Workshop(December 17th 2018 in Frascati)

Organized under the auspices of the LNF Director Dr. Pierluigi Campana

Scientific Committee:L. Rivkin (EPFL and PSI, chair)C. Bloise (INFN-LNF)A. Ghigo (INFN-LNF)M. Giovannozzi (CERN)C. Milardi (INFN-LNF),N. Pastrone (INFN-Torino)A. Variola (INFN-LNF)

Local Organizing CommitteeA. Drago (INFN-LNF, chair)S. Caschera (INFN-LNF)A. De Santis (INFN-LNF)O. R. Blanco Garcia (INFN-LNF)


25 proposals

96 participants from: CERN, Switzerland, Italy, Germany, Austria, Japan, China, USA

https://agenda.infn.it/event/16334/

https://agenda.infn.it/event/16334/


DAFNE-TF Workshop Program


( FCC Design Group)

FCC-ee as a possible first step

DAFNE-TF as test bench to study the Future Circular Hadron Colliders Issues (CERN)








Impact of Radiation damping on beam dynamics and on collisionsCollective effects

• Beam-Beam behaviour and limitsexplore possible B-B limitation in the case of large B-B parameter (0.03 – 0.06)

in presence of external noisefor different damping time with and without LRBBas a function of the colliding angle with and without Crab-Waist

• Coherent effects (beam-beam, impedance and e-cloud) and theirmutual interplay

• Beam stability measurements to study Landau damping trends in presence of (beam-beam, impedance and e-cloud)

Optics issues• Beta beating and emittance growth due to head on collisions and their

impact on the collimation system design• Local chromaticity compensation in low beta sections

DAFNE-TF could be unique playground to:study collective effects and optics issues relevant to the future collidersprovide reliable data to be used to validate simulation codes

DAFNE-TF as test bench to study Future CircularHadron Colliders Issues (CERN)


Concern for LS2 and LS3 until the cause for the higher heat load is not fully understood.

And the situation is not going to be better with HL-LHC beams…

( Paolo Chiggiato )

DAFNE-TF as test bench for vacuum equipmentand surface treatments (CERN proposal)

DAFNE contribution on the short term:• dedicated e-cloud studies to clarify the origin of the high

heat load observed in few arcs at LHC• systematic studies on carbon coating, which is the main

technique foreseen to keep under control the excessive heat load on the HL-LHC triplet magnets


DAFNE contribution on the long term:• characterize new components in terms of impedance• Systematic measurements on LASER treated surface as a

function of the laser parameter in order to achieve an optimal trade-off between e-cloud mitigation and impedance

• measure synchrotron radiation impact on vacuum systems• test NEG coating in order to optimize film thickness without

compromising the NEG coating activation efficiency• provide reliable experimental data to be used for validating

simulation code• characterize coating with high temperature superconductor

Running Colliders can dedicate very limited time to equipment test and measurementsDAFNE can become the reference Lab for synchrotron radiation studies in vacuum technology.




• Present FBK architecture has a fundamental limits coming from noise and Group Delay limitation, it cannot meet the requirements of future colliders requiring control of very high growth rates.

• It would be extremely useful to develop new architectures and test them at DAFNE in order to prove that it’s possible to operate in a regime which is not accessible by the present technology.

New Architecture for Fast Low Noise Feedback


Relying on methods developed for new feedback architecture• tune• tune modulation• non linear tune shifts• tune shift on amplitude

Novel Tune and Beam Diagnostics


1 GHz structure already developed for the intra-bunch feedback at SPS

Installed on January 2018 and commissioned on July 2018

Wideband Kicker structure

• CERN, LNF-INFN, LBL and SLAC Collaboration Design

Report SLAC-R-1037

• J. Cesaratto, S. Verdu, M. Wendt, D. Aguillera,

electrical/mechanical design and HFFS optimization


DAFNE is a valuable and unique infrastructure that should still play a role in the particle accelerator community.

Conclusions

We would be very happy to welcome the Colleagues of the CEPC Design Group


Thank you


Spare slides


DAFNE LINAC

Based on S-band technology

LINAC ParametersPulse width: 1ns ≤ lp < 350 ns f = 2.865 GHz15 accelerating sections4 klystron 45 MW, each one followed by a SLEDrepetition rate 50 Hz

LINAC Beam ParametersEe+ ≤ 550 MeV I+(pulse) ~ 100 mAEe- ≤ 780 MeV I-(pulse) ~ 250 mAε− ~ 1 mm•mrad, Dp/p ~ 1%ε+ ~ 5 mm•mrad, Dp/p ~ 5%

A possible LINAC upgrade aims at reaching Ee- ~ 1. [GeV] by installing additional accelerating sessions

DiagnosticsFluorescent screens 5BPMs 14Current monitors 4Spectrometer 1


DAFNE Accumulator

Energy [MeV] 510

Circumference [m] 32.56

ex [mm•mrad] 0.26

RF f [MHz] 73.65

RF V [KV] 200.

sz [cm] 3.8

SR loss [KeV]/turn 5.2

Damping time tE/tx [ms] 10.7/21.4

All Dipoles and Quadrupoles are based on laminated yoke technologyEnergy operation range up to E = 560 [MeV]

8 450 sector dipole n = 0.53 independent QUAD families2 independent SXT families


Transfer Lines

All Dipoles are based on laminated yoke technology

Dipoles can work up to E ~ 800 [MeV]

Diagnostics Tle Acc inj Tle Acc ext Tlp Acc inj Tlp Acc extFluorescent screens 7 12 5 12

Striplines 9 16 9 10

Current monitors 3 5 3 5


DAFNE ring optics does not have any periodicity, each ring is a cell

Ring optics is based on a modified Chasman-Green lattice It consists of 4 achromats, each one including a 2 m long normal conducting wiggler allowing to tune over a wide range:

beam emittanceradiation dampingmomentum compaction

Ring optics is very flexible since all Quadrupole and Sextupole magnets are independently powered

Main Rings

IP

e- inj

e+ inj

RCR


All magnets are based on laminated yoke technology.

All Quadrupoles and Sextupoles in the Main Rings are independently powered

Wiggler are series powered in each Main Ring

Magnets: Dipoles can work and have been characterized up to E ≤ 530 [MeV]Large quadrupoles |Kq|E ≤ 2224 [MeV m-2]Small quadrupoles |Kq|E ≤ 3200 [MeV m-2]

Large Sextupoles |Ks| Ls E ≤ 7500 [MeV m-2] Small Sextupoles |Ks| Ls E ≤ 6666 [MeV m-2]

RF systems:fRF = 368.667 [MHz]VRF = 250 � 300 KV 120 harmonic number

Main Rings

Diagnostics in each ring Number Details

BPMs 46 4 buttons, Bergoz acq. 6 Hz,resrms = 5÷10 µ

BPMs 6 8 buttons for diag. and FBKs

Libera modules 4 res ~ µ

DCCT 1

SRM 1

Streak Camera 1 res ~ 10 ps

Gated Camera 1 gate time ~ 20 ms, res ~ 20 µ

FFT spectrum analyser+ white noise generator 1 Tune measurements

Scope 2

FBK systems 3


DAFNE Cryogenic System

LINDE TCF 50 liquid He refrigeration plant

• Users: KLOE/FINUDA/4 Antisolenoids

• Operated at DAFNE 1998-2018

• Refrigeration capacity:

• 100 W @ 4.4K/1.2 bar

• 1.14 g/s LHe

• 900 W @77 K/10 bar

• Distribution valve box for 6 users

• Control system updated on 2014

• Plant compressor replaced on 2016

G. Delle Monache, C. Ligi


DAFNE Energy Saving and Operating Costs

Wiggler pole shaping and current reduction(730-> 400 A)

1700 kW

n. 4 Septa 34�magnets new coils 250 kW

n. 4 Splitter magnets removal (new interaction zone for the crab-waist)

160 kW

Dafne RF system optimization 170 kW

Dafne cooling system optimization 280 kW

Total power demand reduction 2.560 kW

kW €cent/kWh K€/day

1 year bill (200 run days)

[M€]

Up-to date 1 year bill

[M€]Run KLOE 2005-2006 5.900 9,8 13,88 2,78 5,12 Run KLOE (Dec 2013) 3.340 18,08 14,49 2,90 2,90

Power demand reduction = 2.560 200 days run saving = 2,22

[KW] Dec-2005 KLOE-2

Magnets Powersupplies* 3.984 1.850

RF MR 524 320Linac 201 233

Cooling 600 300Criogenic plant 250 250

HVAC 250 260 Kloe 150 120 TOT 5.959 3.333

(R. Ricci)

* Wigglers contribute to the power demand for an amount of 740 KW


•Large Piwinski angle and Crab-Waist scheme proved to be effective in increasing luminosity, a factor 3 higher than in the past

•The new approach to collision provided

Lpeak= 4.5*1032 cm-2 s-1

L∫1 day= 15.0 pb-1

L∫1 hour = 1.033 pb-1

L∫run~ 2.8 fb-1 (SIDDHARTA detector)

Crab-Waist collision scheme and SIDDHARTA


DAFNE upgradeSIDDHARTA

DAFNEKLOE

DAFNEFINUDA

Lpeak [cm-2s-1] 4.36•1032 (5.0•1032) 1.5•1032 1.6 •1032

L∫day [pb-1] 14.98 9.8 9.4L∫1 hour [pb-1] 1.033 0.44 0.5I-MAX in collision [A] 1.47 1.4 1.5I+MAX in collision [A] 1.0 1.2 1.1

Nbunches 105 111 106

xy 0.042 (0.074) 0.025 0.029



DAFNE contribution on the short term:• dedicated e-cloud studies to clarify the origin of the high

heat load observed in few arcs at LHC• systematic studies on carbon coating, which is the main

technique foreseen to keep under control the excessive heat load on the HL-LHC triplet magnets

DAFNE contribution on the long term:• characterize new components in terms of impedance• Systematic measurements on LASER treated surface as a

function of the laser parameter in order to achieve an optimal trade-off between e-cloud mitigation and impedance

• measure synchrotron radiation impact on vacuum systems• test NEG coating in order to optimize film thickness without

compromising the NEG coating activation efficiency• provide reliable experimental data to be used for validating

simulation code• characterize coating with high temperature superconductor

Running Colliders can dedicate very limited time to equipment test and measurements


refrigerator plant LINDE TCF 50 nominal compressor power of 250 kW, delivering two cold He lines:• 4.4 K @ 3.0 bar (100 W nominal power + 1.14 g/s LHe);• 77 K @ 10 bar (900 W nominal power).

G.O. Delle Monache, DAFNE, CR-1 (2005)

existing DAFNE cryogenic systemlayout of DAFNE cryo system for 6 SC magnets

marginal for 4.4 K operation of 1 cavity ?


RF CAVITY LONGITUDINAL KICKER TRANSVERSE KICKER

INJECTION KICKER WALL CURRENT & DCCT MONITOR SHIELDED BELLOWS

HOM Damped Vacuum Chamber Elements

D. Alesini, A. Drago, A. Gallo, A. Ghigo, M. Serio, A Stella, M. Zobov, F. Marcellini, P. Raimondi


DAFNE achievements

• luminosity achieved at DAFNE is almost an order of magnitude higher than the one obtained at other colliders operating in the low energy range

• Impedance budget is a factor 80 lower than in similar storage ring (EPA)

• Collisions with negative momentum compaction gave a 25% gain in termsof specific luminosity at low current without sextupoles

• Longitudinal feedback kicker designed for DAFNE has been adopted at: KEKB, BESSYII, PLS, SLS, HLS, ELETTRA, KEK Photon Factory, PEP II …

• Maximum current stored in the DAFNE electron ring, 2.45 A, is the higherever stored in particle factories and modern synchrotron radiation sources.

• DAFNE is the only collider operating routinely with, and thanks to the electrodes for e-Cloud mitigation

• Crab-Waist collision scheme proved to be an effective approach to increase luminosity in circular colliders even in presence of an experimental apparatus strongly perturbing beam dynamics.

DAΦNE as Open Accelerator Test Facility - CERN Indico

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