Towards a new generation axion helioscope
Igor G Irastorza Universidad de Zaragoza
International Conference onParticle Physics IstambulIstambul,, Turkey,Turkey, June 2020--25th25th 2011 Outline
TlkTalk bbdased on JCAP 06 (2011) 013
OutlineOutline:: – Axions: motivation,motivation, theory,theory, cosmologycosmology.. – Solar axions & the axion helioscopppe concept ––PreviousPrevioushelioscopes & CAST ––TechnicalTechnicalprospects for a new helioscope – Sensitivity prospects ––ConclusionsConclusions
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 2 Zaragoza AXION motivation
Strong CP problem: why strong interactions seem not to violate CP? – CP violating term in QCD is not forbidden . But neutron electric dipole moment not observed. Natural answer if Peccei-Quinn mechanism exist. – New U(1) gl lob al symmet ry spontlbktaneously broken.
As a result, new pseudoscalar, neutral and very light particle is predicted, the axion. It couples to the photon in every model. PRIMAKOFF EFFECT
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 3 Zaragoza AXION motivation: Cosmology
Axions are produced in the earlyyy Universe by a number of processes: – Axion realignment – Decay of axion strings NONNON--RELATIVISTICRELATIVISTIC – Decay of axion walls (COLD) AXIONS
In general, Range of axion masses of 10--66 ––1010--33 eV are of interest for the axionto be the (main component of the) CDM.
– Thermal production RELATIVISTIC (HOT) AXIONS
In order to have substantial relativistic axiondensity, the axionmass must be close to 1 eV.eV. (ma >1.02 eV gives densities too much in excess to be
compatible with latest CMB data) Hannestad et al, JCAP 0804 (2008) 019 [0803.1585 (astro-ph)]
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 4 Zaragoza Solar Axions
SlSolar axi ons prod uced db by ph otonoton--toto-- axion conversion of the solar plasma photons
Solar axion flux [van Bibber PRD 39 (89)] [CAST JCAP 04(2007)010]
Solar physics + Primakoff effect
Only one unknown
parameter ga
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 5 Zaragoza Axion Helioscope principle
Axion helioscope [Sikivie, PRL 51 (87)]
AXION PHOTON CONVERSION
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 6 Zaragoza COHERENCE 1 Helioscopes Previous helioscopes: – First implementation at Brookhaven (just few hours of data) [Lazarus et at. PRL 69 (92)] – TOKYO Helioscope (SUMICO): 2 .3 m long 4 T magnet
Presently running: – CERN Axion Solar Telescope (CAST) ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 7 Zaragoza CAST experiment @ CERN Decommissioned LHC test magnet (L=10m, B=9 T) Moving platform ±8°V ±40°H (to allow up to 50 days / year of alignment) 4 magnet bores to look for X rays 3 X rays detector prototypes being used. X ray Focusing System to increase signal/noise ratio.
LHC test magnet
Micromegas TPC (<2007) & 2 Micromegas CCD/Telescope (>2008)
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 8 Zaragoza New Micromegas detectors for CAST
Since 2008 2 new Micromegas detectors replaced the TPC in the sunset side. – Better shielding At sunrise side. The Micromegas detector substantially upgraded: – microbulk, shielding, monitoring, frontal calibration , flow controller , In overall increasingly better Sunset backgrounds & sensitivity Micromegas
Sunrise Micromegas
See talk by C. Yildiz
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 9 Zaragoza CAST X -ray telescope
CAST innovationof the “helioscope concept”
Wolter I typegrazing incident optics (prototype (prototype for ABRIXAS mission)mission) From Ø43 mm ( magnet bore) Ø3mmspot3 mm spot improves signal to background ratio
ICPP, Istambul, June 2011Igor G. Irastorza / Universidad de 10 Zaragoza CAST X -ray telescope
Tracking data Signal simulation Spot from the telescope on the CCD detector Determination of the spot position by calibrations and precise alignment of tltelescope. Counts inside the spot compatible with background level
ICPP, Istambul, June 2011Igor G. Irastorza / Universidad de 11 Zaragoza 11 ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 12 Zaragoza Towards a new generation axion helioscope
Ingredients of a successful helioscope CAST is established as a reference result in experimental axion physics (*) CAST PRL2004 most cited experimental paper in axion physics No other technique can realistically imppgrove CAST in a wide mass range. Large & powerful magnet...
Next step in the field new generation axionheliosco pe ...X-ray optics,...
CAST has shown the way to improve the helioscoppqe technique…
...and low background detectors
ICPP, Istambul, June 2011Igor G. Irastorza / Universidad de 13 Zaragoza 13 Axion Helioscopes FOM
3 elements drive the sensitivity of anaxion helioscope
X-RAY X-RAY MAGNET OPTICS DETECTORS
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 14 Zaragoza Sensitivity scenarios
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 15 Zaragoza New magnet
CAST enjoys one of the best existing magnets than one can “recycle” for axion physics (LHC test magnet) OlOnly way to mak e a step f urth er is to built a new magnet, specially conceived for this. Work ongoing, but best option up to know is a toroidal configuration: – Much bigger aperture than CAST: ~1 m per bore – Relatively Light (no iron yoke) – BB(?)ores at room temperature (?)
Cross section of the magnet
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 16 Zaragoza Inspired by ATLAS… ?
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 17 Zaragoza X-ray optics
During the last four decades, the x-ray astronomy community has devoted billions of dollars to develop reflective xx--rayray optics XMM-Newton Innovations include: telescope with 56 – Nested designs (so called Wolter telescopes) nested shells ––LowLow--costcost substrates – Highly reflective coatings
Although NGAH will require fabrication of dedicated optics, it will be crucial to leverage Ni E = 4.5 keV as much infrastructure as possible to minimize σ = 0–20 Å cost and risks
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 18 Zaragoza One possibility: thermallythermally--formedformed glblass substrates NASA is currently building NuSTARNuSTAR,, a hard x-x-rayray telescope
NuSTAR uses thin glass substrates coated with multilayers to enhance reflectivity up to 80 keV NuSTAR optics assembly machine The specialized tooling to shape the substrates and assemble the optics will be available after NuSTAR is launched in 2012
Hardware can be easily configured to make optics with a varitiety of fd des igns and si zes NuSTAR ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de telescope 19 Zaragoza An ultralow-b MM for the NGAH
Goal: at least 10--77 c/c/keVkeV/cm/cm2/s, simulations dt10down to 10-8 c/kVkeV/cm2/if/s if possible. Work ongggoing: – Experimental tests with current detectors at CERN, Saclay & Zaragoza – Especially: underground setup at Canfranc Lab
– Simulation works to build up a See talks by background model C. Yildiz & ––DesiDesign a new detector with T.T. DafniDafifni improvements implemented R&D low background detectors Latest Micromegas: x20 improved History of background improvement of Micromegas detectors at CAST background ––ShieldingShielding 2003 Nominal values at CAST – Radiopurity. New manufacturingtechnique 2004 2006 (microbulk readouts) ––MoreMore powerful offline cuts 2008-10 Tests in controlled conditions underground at Canfranc: – Better shielding coverage – Thicker shielding
Backgrounds around 2x10-7 c/keV/s/cm2 with improved shielding ~ x30 better than CAST
See talks by C. Yildiz & T. Dafni How much beyond CAST we can hope for?
Factor 8 to 30 better in 6 ga (4000 to 10 in signal strength!!)
Conservative scenario Realistic scenario
Optimistic scenarios
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 22 Zaragoza How much beyond CAST we can hope for?
Much larger QCD axion region explored
Helioscopppe prosp ects
In combination with dark Astrophysical matter axion searches a hints for ALPs big part of the QCD axion modldel region could ldb be explored next decade.
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 23 Zaragoza The cooling of white dwarfts (Isern et al. 2008,2010) Luminosity function (WD’s (WD’sper unit magnitudemagnitude)) altered by axion cooling Claim of detection of new cooling mechanism (Isern 2008 ) AxionAxion--electronelectron coupling of ~1x10--1313 ( axion massesof 2-2-55 meVor larger) fits data .
DFSZ axion (cos=1)
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 24 Zaragoza The cooling of white dwarfts
meV masses seem out of reach of EXTRA bremstrahlung emission ~50 times even an improved axion helioscope… helioscope… larger than standard Primakoff emission BUT Axion-electron coupling provides extra axion emission from the SunSun…… Extra emission concentrated at lower energies (~1 keV)
Such axion could produce a detectable signal in the new axion helioscope
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 25 Zaragoza Conclusions
CAST most powerful axion helioscope to-date. Established as a reference result in axion physics. Expertise gathered in magnet, optics, low back detectors
Towards a new generation axion helioscope: feasibility study in progress. First results (JCAP 016) show good prospects to improve CAST 1-1.5 orders of magnitude in ga. In combination with dark matter axion searches (ADMX) a big part of the QCD axion model region could be explored next decade. White dftdwarftse-coupldled axi?ions?, relicaxi?ions?, ALPs?… towards an International Axion Observatory Looking for more interested ggproups…
ICPP, Istambul, June 2011 Igor G. Irastorza / Universidad de 26 Zaragoza