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Status Report of Status Report of CERN Axion Solar Telescope (CAST) CERN Axion Solar Telescope (CAST)

ExperimentExperiment

Dieter H.H. Hoffmann(Tech. University Darmstadt & GSI – Darmstadt)

on behalf of the CAST collaboration

ICHEP, Moscow July 27ICHEP, Moscow July 27thth 2006 2006

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Summary of presentation

• Brief CAST overview • Analysis of 2004 data (phase I)• CAST phase II• Schedule for next months• Conclusions

CAST Collaboration

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CERN and CAST

CAST

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CAST working principle Sikivie [1983]

Axion source Axion detection

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CAST historyCAST history

2002 2003 2004 2005 2006

CAST construction

CAST phase I CAST phase II

First commissioning runs

First Physics runs

Physics runs – Enhanced operation

Work to upgrade for phase II

First physics runs – phase II 4He

Phase II (4He) operation

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Cern Axion Solar Telescope

Thomas Sahner

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CAST setup overviewCAST setup overview

LHC test magnet

TPC

Micromegas&

CCD/Telescope

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Tracking System:

Calibrated and correlated with celestial coordinates

Tracking System:

Calibrated and correlated with celestial coordinates

Twice a year (September&March) we can

film the Sun through the window

Twice a year (September&March) we can

film the Sun through the window

Looking at sunrise

Magnet, sun tracking

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TPC

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HECμM

XRTCCD

HEC

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keV4.2Ea

Solar axion spectrum

Paγ 1.710-17

2

GeV10

g110

aγγ

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~33% →

On-Axis Effective Areas at PANTER and at CAST

0.0

2.0

4.0

6.0

8.0

10.0

12.0

0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5

Energy [keV]

Calculated effective area in PANTER (48 mm diameter aperture)

Measured Effective area in PANTER (48 mm diameter aperture)

Expected effective area at CAST (42 mm diameter aperture)

The effective area of the X-ray telescope f (Eγ).

↓ 4.5 keV

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2004 data analysis2004 data analysisCCD/Telescope

• Spot position well determined• Full sensitivity of telescope

exploited• Counts inside the spot

compatible with background level

Tracking data Signal simulation

•No axion signal detected

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2004 data analysis2004 data analysis

TPC 2004 subtracted spectrum Micromegas 2004 subtracted spectrum

• ~200 h of tracking data for each detector• Almost non-interrupted operation. High quality data

•No axion signal detected

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2004 result2004 result

for

• New exclusion plot, improving 2003 result

• Factor of 7 improvement beyond previous experimental searches.

• It goes beyond astrophysical limit of globular clusters for coherence masses

• Publication now under preparation

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CAST phase II – principle of CAST phase II – principle of detectiondetection

Extending the coherence to higher axion masses...•Coherence condition (qL << 1) is recovered for a narrow mass range around m

Ne: number of electrons/cm3

: gas density (g/cm3)

axionsTransverse magnetic field (B)

X ray

X raydetector

L

Aaxions

Transverse magnetic field (B)Transverse magnetic field (B)X ray

X raydetector

X ray

X raydetector

X ray

X raydetector

L

A

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CAST phase IICAST phase II

• CAST phase II approved CAST phase II approved by CERN Research Board by CERN Research Board on Dec 2004on Dec 2004• Data taking with Data taking with 44He He started last Novemberstarted last November• 33He phase will start mid He phase will start mid 2007 (LLNL will provide 2007 (LLNL will provide the the 33He)He)

CAST phase II sensitivityCAST phase II sensitivity

Cosmological limit Cosmological limit (Hannestad et al, JCAP 0507 (05) 002)(Hannestad et al, JCAP 0507 (05) 002)

Presentprogress

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ScheduleSchedule

2006 July Aug Sep Oct Nov Dec

Data taking with 4He • 1 step per day

• tests for ramping?

3He system road map

Complete TDR

Complete Add. MoU

TD Review Start construction components

New detection line MM+optic

PANTER tests

Installation in CAST

P ~ 9 mbarP ~ 9 mbarmmaa ~ 0.31eV ~ 0.31eV

PP ~ 12 mbar~ 12 mbar

mmaa ~ 0.37eV~ 0.37eV

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ScheduleSchedule

2007 J F M A M J J A S O N D

3He System

Installation in CAST

Commissioning

Data taking

• Start 3He

physics runs• Double step• Possibility of ramping mode?

2008 2009

Data taking • Time needed to fully exploit new setup

P ~ 45 mbarP ~ 45 mbarmmaa ~ 0.71 eV ~ 0.71 eV

P ~ 120 mbarP ~ 120 mbarmmaa ~ 1.16 eV ~ 1.16 eV

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ConclusionsConclusions• CAST has successfully performed its transition into

phase II:• Phase I data analysis finished. Publication under preparation• Upgrades to start phase II done during 2005: 4He system, cold

windows• Phase II 4He data taking ongoing

• Started in Nov 2005• Up to 4 mbar scanned already. 4He runs planned until the end of

the year• Installation of new detector line with a second X-ray

optics planned before the end of the year• Phase II 3He operation scheduled for mid next year

• 3He system designed. Technical report in preparation• Schedule for next months has been presented• CAST will reach 60 mbar (0.8 eV) during 2008• 3He allows extension to even higher masses (1.16 eV)