The Gravitational Wave Detetor
\Mario Shenberg": Status of the Projet
O.D.Aguiar 1
,L.A. Andrade 1
, L. Camargo Filho 4
, C.A. Costa 1
,J.C.N. de Araujo 1
,
E.C. del Rey Neto 1
,S.T. de Souza 2
,A.C. Fauth 4
, C. Frajua 5
,G. Frossati 7
,
S.R. Furtado 1
,V.G.S. Furtado 1
, N.S. Magalh~aes 6
, R.M.Marinho Jr. 3
,
E.S. Matos 1
, M.T. Meliani 1
, J.L. Melo 1
,O.D. Miranda 1
, N.F. Oliveira Jr. 2
,
K.L. Ribeiro 1
,K.B.M. Salles 1
, C. Stellati 3
, W.F. VellosoJr. 1
1. InstitutoNaionaldePesquisas Espaiais-Divis~aodeAstrofsia,S~aoJosedosCampos,S.P.,Brazil
2. Universidade deS~aoPaulo-InstitutodeFsia,S~aoPaulo,SP,Brazil
3. InstitutoTenologiode Aeronautia, S~aoJose dosCampos,SP,Brazil
4. UniversidadeEstadual de Campinas-Institutode Fsia,Campinas,SP,Brazil
5. CentroFederalde EnsinoTenologiodeS~aoPaulo,S~aoPaulo,SP, Brazil
6. UniversidadeBandeirantede S~aoPaulo,S~aoPaulo,SP, Brazil
7. LeidenUniversity-KammerlinghOnnesLaboratory, Leiden,TheNetherlands
Reeivedon31January,2002
Therst phase ofthe Brazilian Graviton Projet is the onstrutionand operation of the
grav-itational wave detetorMario Shenbergat the PhysisInstitute of theUniversity of S~ao Paulo.
Thisgravitationalwavespherialantennaisplannedtofeatureasensitivitybetterthanh=10-21
Hz-1/2atthe3.0-3.4kHzbandwidth,andtoworknotonlyasadetetor,butalsoasatestbedfor
thedevelopmentofnewtehnologies. Herewepresentthestatusofthisdetetor.
I The projet[1℄
Theantennawillweightabout1150kg[2℄,whihisonly
a fatorof 2less massive than existent antennas. By
ooling it to muh lower temperatures (15 20mK),
however,andbymakingitspherial(omnidiretional),
weexpetaonsiderableimprovementinsensitivity[3℄.
The projet will be divided in two phases:
GRANTEDphaseanddetetorphase. Inthe
Gravita-tionalRadiationANtennaTEhonologyDemonstration
phase(GRANTED),wewilltestthefollowingaspets:
a) the feasibility to onstrut a heavy ( 1150kg)
opper-aluminum (94% 6%) spherial mass, whih
presentsahigh(Q
m
>107)mehanialFigureofMerit
at20mK [4℄;
b) thefeasibilityto quikly(less than aweek)ool
suhamassdownto 20mK[5℄;
)thefeasibilitytoextratandanalyzedatafroma
transduerattahedtothespherialsurfae;
d) the feasibility to protet suh a spherialmass
fromlaboratoryandenvironmentvibrationsbytheuse
ofdesignedvibrationisolationsystemsforthemass
sus-pension, the dilution refrigerator and the transduer
wiring.
phase(GRANTED),weintendtoonstrutandplaea
set ofhigh sensitivitytransduersattahed tothe
sur-fae of the sphere, transforming the above prototype
intoaneetivegravitationalwavedetetor,theMario
SCHENBERGdetetor,inthe3:0 3:4kHz frequeny
bandwidth.
II The sienti goals of the
present detetor
A 65m-diameter Cu Al (94% 6%) antenna will
be overing the 3:0 3:4kHz bandwidth, whih has
astrophysialimportane. Itwouldbeoperatingin
o-inidenewiththeDuthMini-GRAIL andtheItalian
SFERA antennas,and somelargelaser interferometer
detetors, whih an also over suh high frequenies
withsimilarsensitivities [6℄.
Theastrophysialeventsthatweantiipateas
prob-able andidates for detetion in the 3:0 3:4kHz
re-gion, where the SCHENBERG detetor will be
sensi-tive, are [7℄: ore ollapse in supernova events;
neu-tronstarsgoing tohydrodynamialinstability; quakes
the rst quadrupole normal mode of 3:8M
blak
holes; oalesene of 1:9M
neutron stars and/or
blakholes.
Wealsoanspeulatesome\exoti"souressuhas:
rotationofbosoniorstrangematterstarsat1:6kHz;
inspirallingofmini-blakholebinaries.
III The Shenberg group
Thegroupis dividedin sixmajorsubjets:
1)Cryogenis,withProf. NeiOliveiraJr. (Co-PI),
Prof. Giorgio Frossati (Co-PI), Karla Salles (Master
student), SergioFurtado (Master student),and Sergio
deSouza (Masterstudent);
2)Astrophysial SouresandGravitation,withDr.
Jose C.N. de Araujo, Dr. Oswaldo D. Miranda, Dr.
MaraMeliani,andDr. EdgarddelReyNeto[8℄;
3)Vibration Isolation,with Dr. Walter VellosoJr.
andJoseMelo(Ph.D.student)[9℄;
4) Transduers, with Dr. Carlos Frajua, Kilder
Ribeiro(Ph.D.student),andLuizAndrade(Ph.D.
stu-dent);
5) CosmiRayDetetion Hardware, with Dr.
An-dersonFauthandLuioCamargoFilho(undergraduate
student);
6)DataAnalysis,withDr. RubensMarinhoJr.,Dr.
Nadja Magalh~aes, ClaudemirStellati (Ph.D. student),
CesarCosta(Masterstudent),ValeriaFurtado(Master
student),andEmlioMatos(MasterStudent)[10℄.
The Brazilian group is developing this projet in
ollaboration with the Duth group and all four
ma-jorgroupsoperatingryogeniresonantmassantennas
(ALLEGRO, NAUTILUS & EXPLORER, AURIGA
and NIOB
E). It also reeives ollaboration from
re-searhersandprofessorsworkingatsomeother
Brazil-ian institutions and universities and at somelaser
in-terferometer projets(LIGO,VIRGO,andLISA).
IV The status of the detetor
IV.1 Site preparation
ThesitepreparationattheUniversityofS~aoPaulo
is under theoordinationofN. OliveiraJr., andis
al-most ompleted. A pit has been onstruted in one
of hislaboratoryrooms,wherethedetetor willbe
lo-ated. There isone hydrauli pistoninside a onrete
olumn at eah of the four orners of this pit. These
pistonsformahydraulisystemthatanliftupto2m
areinfored4 tononretebase,onwhihthe
dete-tor will be assembled. A rane has been installed on
the topof a sliding struture onneted to the upper
part of the room walls. This rane together with the
hydrauli system will provide some exibility for the
IV.2Cryogeni hambers
The ryogenihambershavebeen designedby G.
Frossatiand ollaborators. Theywill beshippedfrom
KADEL(USA)in Otoberof2001,andwillbe
assem-bledontheonretebase assoonastheyarriveatthe
UniversityofS~aoPaulo.
Frossati has also designed thedilution refrigerator
thatisgoingtobeused inthedetetor.
IV.3Vibration isolation system
Thevibrationisolationsystemthat willbeusedin
theMarioShenbergdetetoristheprodutofa
teh-nologydevelopedby various gravitational wave
dete-torgroupsinafewdeadesofexperiene. Thedesigned
oneusesC springsthat wereproposedbyItalians
ol-laborators. Meloand Vellosohavedonesomedetailed
alulationsusingthisdesignandaniteelement
soft-ware (NASTRAN). They were ableto design a
vibra-tionisolationsystemfree fromresonanes loseto the
3:0 3:4kHz frequeny band. This system, that will
beinsidetheryogenihambers,togetherwitharoom
temperaturevibrationisolation systemverysimilar to
theone used by theALLEGROdetetor, will beable
to attenuate morethan 360dB the vibrationsoming
thoughtheantennasuspensionsystem.
ThissystemwillbeastatITALBRONZE(Brazil),
andwillbedeliveredbytheendof2001.
IV.4Sphere
A rst spherial antenna has been ast by
ITAL-BRONZE (Brazil) at the beginning of 2001. It was
senttotheDuth groupfortesting.
The Shenberg antenna will be ast at
ITAL-BRONZEbytheend of2001.
IV.5Transduers
Weplantouseasetofseventwo-mehanial-mode
parametri transduers pumped at about 10GHz for
monitoringtherstmonopole(onetransduer)andrst
ve quadrupole (six transduers) modes of the
spher-ialantenna. This will be done in ollaboration with
theAustraliangroupandwithothergroupsinBrazil.
IV.6Shedule
Therstryogenirun issheduletothebeginning
of2002andthersttransduertesttoaboutsixmonths
later. Finally,weplantoputthedetetorina
ommis-sioningphasesometimein 2003.
Aknowledgments
This work hasbeensupportedby FAPESP(under
grants No. 1998/13468-9, 1996/01872-4,
1997/06024-4, 1999/10809-2, 2000/10374-5, 2001/04189-3,
2001/04086-0, 2001/04226-6), CNPq (under grants
Referenes
[1℄ ProposalsubmittedinNovemberof1998andapproved
byFAPESPinApril2000
[2℄ TheinitialproposalwasaCu Al (6%)800kg
buky-ballantenna.However,inommonagreementwiththe
Mini-GRAILandSFERAgroupswedeidedtohange
it to a Cu Al (6%) 1150kg spherial antenna. The
highfrequenyoperation oftheantennarequires that
thetransduersbelampedattheantennasurfae
in-steadof bolted, therefore therewouldbe noneed for
atsurfaes(normallyrequiredforboltingtransduers)
and so, for a polyhedronshape antenna.Thenatural
spherialshapealsohasmoremass(morerosssetion
to the waves). Thediameter was inreased too (from
60mto65m)beausewehadmoreroominthe
ryo-genihambersandbeausethe3:0 3:4kHzfrequeny
windowseemed moreinteresting fromthe
astrophysi-alpointofviewofthegravitationalwavesoureslisted
onx2omparedtotheoriginal3:9 4:3kHzfrequeny
one. For example, for hydrodynamial instabilities of
neutronsstars,Houser(1998Mon.Not.R.Astron.So.
299,1069)showedthatafrequenybandbelow3:5kHz
wouldhavemorehanestoseeastrongersignal
[3℄ Forward, R. L. 1971 General Relativity and
Gravi-tation 2, 149. Wagoner, R. V. and Paik, H-J. 1977,
ProeedingsoftheAademiaNazionaledeiLinei,
In-ternational SymposiumonExperimentalGravitation,
Pavia, Italy, Sept. 1976, p.257. Johnson, W. W. and
Merkowitz, S. M. 1993 Physial Review Letters 70,
2367. Coia, E. 1997, 14thInternational Conferene
on General Relativity and Gravitational, Florene,
1995, World Sienti, Singapore, pp. 103. Waard,
A. and Frossati, G. 2000, Proeedings of the Third
Edoardo Amaldi Conferene on Gravitational Waves,
1999, Pasadena, California. AIPConferene
Proeed-ings.AmerianInstituteofPhysis523,268
[4℄ Frossati,G.etal.1997,ProeedingoftheFirst
Interna-tionalWorkshopofOmnidiretionalGravitational
Ra-diationObservatory,S~aoJosedosCampos,Brazil,May
26-31,1996,editedbyW.F.Velloso,O.D.Aguiar,and
N.S.Magalh~aes,WorldSienti,Singapore,179
[5℄ This has already been demonstrated by the Duth
[6℄ ProeedingsoftheThirdEdoardoAmaldiConferene
on Gravitational Waves, 1999, Pasadena, California.
AIP Conferene Proeedings. Amerian Institute of
Physis523(2000)
[7℄ Wagoner, R. V. 1984 Ap.J. 278, 345. Shutz, B. F.
1997, Relativisti Astrophysis andGravitational
Ra-diation, eds. J-A.Mark and J-P.Lasota, Cambridge
Univ. Press. Anderson, N. and Kokkotas, K.D. 1996
Phys.Rev. Lett, 774134. Anderson, N.; Araujo, M.
E. andShutz, B.F.1993 Class. QuantumGrav. 10,
757. Friedman,J.L.;Ipser, J.R.andParker,L. 1989
Phys.Rev.Lett.623015.Haensel,P.;Lasota,J-P.and
Zdunik,J.L.1999preprint(astro-ph/9905036).
Naka-mura, T.; Sasaki, M.; Tanaka, T.and Thorne, K. S.
1997 Ap.J.487L139.Thorne,K.S.1987,300Years
of Gravitation, edited by S. Hawking and W. Israel,
CambridgeUniv.Press,Cambridge,pp.330.Harry,G.
M.; Stevenson, T.R.and Paik,H-J.1996 Phys.Rev.
D542409
[8℄ deAraujo,J.C.N.;Miranda,O.D.andAguiar,O.D.
2001 Ap.J.550368. Meliani,M. T.;deAraujo,J.C.
N.andAguiar,O.D.2000Astron.Astrophys.358417.
deAraujo,J.C.N.;Miranda,O.D.andAguiar,O.D.
2000Phys.Rev.D61124015.Novello,M.;Loreni,V.
A.; Freitas,L. and Aguiar,O.D. 1999 Phys.Lett.A
254245.Mosquera-Cuesta,H.J.;deAraujo,J.C.N.;
Aguiar,O.D.andHorvath,J.E.1998Phys.Rev.Lett.
802988
[9℄ VellosoJr.,W.F.;Melo,J.L.andAguiar,O.D.2000
Rev.Si.Instrum.712552
[10℄ Magalh~aes,N.S.;Aguiar,O.D.;Frajua,C.and
Mar-inhoJr., R.M.2001 Nul.Instrum.Meth.Phys.Res.
A457175. Magalh~aes, N.S.; Aguiar, O.D.; Frajua,
C.; Marinho Jr.,R.M. andChiang,J.2001 Nul.
In-strum.Meth.Phys.Res.(inpress).MarinhoJr.,R.M.;
Magalh~aes,N.S.; Aguiar,O.D.andFrajua,C.2001
Phys.Rev.D(inpress).Magalh~es,N.S.;Johnson,W.
W.; Frajua, C. and Aguiar, O.D. 1997 Ap.J. 475
462. Magalh~aes, N. S.; Aguiar,O.D.and Frajua, C.
2001Phys.Rev.D(inpress).Magalh~aes,N.S.;Aguiar,
O.D. andFrajua,C.1997 Gen.Rel. Grav. 291511.
Magalh~aes, N. S.; Johnson, W. W.; Frajua, C. and
