Low-temperature semiconductor resistance thermometer with heat conductor

Low-temperature semiconductor resistance thermometer with heat conductor S.P. L o g v i n e n k o a n d O.A~ R o s s o s h a n s k i i Inslilute for Low Temperalure Physics and Engineering, UkrSSR Academy of Scnences, 47 Lennn Avenue, Kharkov 310164, USSR Received 22 February 1984 A 0 . 5 - 1 0 0 K GaAs Ihermomeler wnlh a Iorotdal elemenl and a heal conduclor 0mproving Ihe thermal conlacl and mechanical slrenglh ~s described. AI 4.2 K the reproducib,liry ,s 10 mK and the Ihermal res,slance us about 104 KW -1 for P -'= 10 -6 W. Keywords: cryogenics; thermometers; semiconductors; resistance t h e r m o m e t e r s

When ()perallntJ, w,lh a h)w-lemperalure semnc~)nduch)r res)slance Iherm()meler. Ihe vahd signal is deLe.rmmed by paramelers (reslsiance, (_)perulmg currem) Ihe values (_)1 wh)ch are I)mlled by p()ss,hle ()verheal~ng ol Ihe sensing elemenl due h)J()tule heal A new 'T'SAD4K resistance Iherm()meler ()perallngby a h)ur-lead clrcull(Fig /)was des)~.)ned h),reprove heal Iransler A reduct,(.)n ~n heal reslSlall~.'e helween Ihe sel,slng elemenl and Ihe medtum measured ~s achieved hv placing Ihe sensnn~ elemenl ori a heal c~mduch)r made Ir~m a c~pper rod(Ihe PF'TV wnre ,s

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062 mm dnameler) The heal c~mduch~r ts ele~.lrncally ns()laled Ir(mn Ihe 2 rrim dlameler cvhndrlcul (_~aAs Zn sensing element wnlh a II 7 mm axial bore Currenl and polenlnal c~mlacls, In/l% Zn, are h~cated on opposile cylnnder planes, and Iheir mulual arrangemenl ullecls Ihe value ~1 p~qenllal c~mlacl signal acc~rdlng lo Ihe h)rmula I./.(I-stn a) h~r() '._ at '__ 7t/2. where I1. us Ihe vollage al Ihe p()lenllal ccmlacls h~r or = (). and e is Ihe angle hetween planes parallel h)Ihe cyhnder axts and passing lhrough Ihe currenl and polenl.ul c~mlacls Leads made of ,nsulaled copper ¢onducl~)rs ((I()X mm dnameler) pnwlde heal Irunsler irom Ihe senstng elemenl Ihrough several coils wound onh~ Ihe heal eonduclor. 'The copper case ns I'dled wilh helnum gas al a pressure ol ~ . lip Pa. The Ihermq~meler-lest ohjecI heal Iransler can he aceompl.shed Ihn)ugh Ihe heal conduch~r hi Ihe lesl ohlecl hxed b~ screw, soldered ~r welded (Ihe cane lemperalure ns I() he no more Ihan 3'73 K) Wnlh Ihe sensing elemenl I)xed, Ihe resnslance thermomeler can be used al higher loads The I-1' characlernsl,cs from reslslance Ihermometers of Ihe 17pes TSAD2-1, T S A D 2 - 2 ' a n d T S A D 4 1 ( ,mmersed nn Inquid h e h u m at 4.2 K were laken ,n Ihe region I ,' I(I-~ Iol . I() "~ A ( G a . A s s e n s i n g e l e m e n l s ) a n d are shq~wn nn Fig J 'The I- l" characlensllc li)r Ihe TSAD2- I res,slance Ihermomeler m which Ihe sensnng elemenl- lesl mednum heal Iransler occurs Ihrough leads a n d heal Iranslergas. nsshown h v c u r v e I A I I h e n n , l n u l p o r l , o n o l Ihe curve Ihe dependence ns linear As Ihe currenl ,s nncreased, the res.slance Iherm~m, eler heats up resulltnt., nn a reducl,on ~1' his resu~lance and nn Ihe dependence nonlnnearnl~, F(~r Ihe'T'SAD2-2 reslslance Ihermomeler. which has a case wllh an trripr~wed c~mvecllVe heal exchange and where Ihe heal Iransler ns acc,,mpl,shed Ihr()uph slrlp leads .n Ihermul c~mlacl with Ihe cane, hq.:h currenl can he supplied w,lh,.ul h,ss nn Ihe I - I ' curve I.nearntv (curve 2) 'The I - I characlernsl.c Irom Ihe 'TSAD4 K reslslance IherrriLmieler issh~wn by curve ~ ']"he resulls obtained ,ndicale Ihal Ihe heal res,slance of Ihe 'TSAE)4K Iherm,,meler reduces I,, Ihal ~)1 Ihe sensing elemenl ~mnier,~ed d.recllv .n Inqund hel.um 'The same resulls were ,~hlatned h,r Ihe ah,)ve resnslance Iherm~, reelers al I '~ K ,n Inqu,d and L:;-is

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The lemperalure ¢haraclerisl)cs ol Ihe re.,,islanee Ihermomeler wHh a G',.tAsZ.n sen~ing, elemetH (Ihe impurl .b/concenlral~on being, ~.'~ . I()'; crn -~) were taken belween ()~ and I()() K 'T'o calibrate Ihe resislanee Ihermomelers h)r the ran~.es ~d'() '~ h~4.2 I,,L4 2 il) 20 K and 2(t Io I()() K, condensall~m He~ and He,~ thermomelers, g,e r m a n i u m '1'SG- I Ihermomelers and p l a l i n u m 'T'SPN-I Ihermomelers were used 'The charaelerlslic is ~.'~lmp~l,~ed of several p(.)rt,on~ of dd'lerenl slupes which are deter. mined by Ihe m.'livallun enerL.,~' for each purl=on (Ft,~ 3) In Ihe ,mpu nW e~mduellc)n porlic)n ( t()- liIO K), Ihe aclwaliun enert..~, ¢~. ,s aboul 1)O2 eV Fur ' r . ~,() I,,L. Ihere clecc, r.s a Irans~llon Io a hopping, mechamsrn ~ll e~mducll~)n wHh Ihe achvaluln enert.,~ ez ,~-,()()()2N eV And I'~lr '/'. I(I K Ihe a¢l,valion ener~,~ decrease.'., morn m m Icallv (r ~.-"=''T' ''~) '1"11is m a re~jon ol ele¢lrlcal c(mduclivil~/wilh a variable leng, lh ()1 the lump as c)pp~sed Io the regjon will) Ihe v~mslanl a¢livallon ener~.,,?/ t'~ where an averatt.e dt,slance hetween irripurilw~ remains unchan~.ed wilh varlalu)ns in lemperalure 'The reprodcielhlli~ ,s a pr,neiple cr,lerum ~.'(inlr~ll IIn~, Ihe elliciency and ¢apablhly ol the res,Mam.'e Ihermumeler.~ Ior precise rrlea.'.,tirenwnl.'., WHh Ihe lhermomelrical parameler wrlllerl d~lwn a.~ a lemperalure equlvalenl, the reproduelbdH3' can he oblamed hy ealculalmg a rc.iI mean square and m a x i m u m devlalion Irom Ihe lemperalLire Io he measured A sel ~1 ~,2 'T'~AD,4K res,slance Ihern,~melers were le.,,led ul ,4 2 K li)r Ihree m~mlhs 'T'hlrleen lesl rLin.~ were perh.)rmed wllh ddlerenl per,(ids o1' time helween Ihem

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and aller eavh run the Ihern)omelers were healed up hi ~,(H) K. For '7~,% ,~11he Iherm(m~elers te.slecL Ihe r(,)l mean square dewul)on does nol exceed I() mK. hall' or Ihe Ihermomelers having, a deviation below '~ mK. 'T'he reprlbduL'lbdlty ol Ihe remain,n~. 2~'~i, is no more Ihan 20 inK. For '7~% of Ihe Ihermomeler.,, Ihe m a x i m u m devlallon d(les nul exceed 21) mK and rur 2~'~i, t0 m R F'c~r 2, 21) and '7'7 K., the r~.)l-mean-square d e v l a l , m ol Ihe malurll3 ' ol'lhe Iherm,lmeler.~ m no more Ihan I(). ~() and '~() m l ~ respeclively 'Thus. Ihe above, resistance Iherrmm)eler wHh Ihe (JaAs Zn ~en,,in~:, elernenl, Ihe at.'l,vall~ln energy ol which reduce.`, wllh lemperalure, enahles Ihe measurernenl range h.i he exlended hlwards low lemperalure.,, as cqDmpared I,) Ihal aeeepled hy 'T'SAD2-I Ihermomelers 'T'hm ,.,, due h~ Ihe lavl Ihat Ihe pracllcal IimH ~.iven hy a m a x i m u m alh)wed value ,)1 Ihe diss,paled Ira)wet .,~eems h) he .~hllled hecause of an iml3r, wed heal Iran~ler hetween sensing elemenl and leMed medium Beside.',, as Ihe measure menls ~1 repr~lduc,hllll3' indlcale. Ihe re~l,~lam.'e Ihermll meier ,n quesl,(m can he ranked as a hlL.~.her preclsl~m w~lrkln~. Iherml)meler hlr Ihe 2-20 K ran.~.e perrnHllng. Iransp()rlal,m l~llll,1~.~ operull~m will) v,hrallons presenl and hnear accelerallons Lip h~ II)4 ,tf Reference I

tA)gvmenko, S.P., Ros~;o~,haw,kii, O.A., Poludich Y V. t,I ol. (_;aA~

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