A modest prehistory of low-temperature detectors

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Nuclear Instruments and Methods in Physics Research A 520 (2004) 4–10

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A modest prehistory of low-temperature detectors

Georges Waysand*

Groupe de Physique des Solides, Universit!e Paris 6, Campus Boucicaut 140 rue de Lourmel, 75015 Paris, France

Laboratoire Souterrain Bas Bruit de Rustrel, Pays d’Apt Universit !e d’Avignon et des Pays du Vaucluse, Rustrel 84400, France

Dedicated to the memory of Sandro Vitale

Abstract

The early days of low temperature detectors are an entanglement between particle physics, astronomy and low-

temperature physics. They are traced from 1903 to the first of the LTD meetings, ‘‘LTD-zero’’, which took place at the

Groupe de Physique des Solides in Paris, in April 1983.

r 2003 Published by Elsevier B.V.

PACS: 29.40; 64.60; 95.55; 01.65; 01.75

Keywords: Detectors; Metastable states; Space telescope; History of sciences; Sciences and society

1. Introduction

This gathering being the 10th session of theLTD meetings, I have been asked by the organiz-ing committee to present their prehistory. Indeed,they are the outcome of a very modest encounter,now nicknamed ‘‘LTD-zero’’. LTD-zero tookplace at the Groupe de Physique des Solides, atthat time associated with Universit!e Paris 7, just 20years ago. It was organized by Fran@ois Vanucciand myself. Sandro Vitale, Director of the Schoolof Medical Physics in Genoa, was one of thespeakers. Sandro is best known to our community

onding author. Groupe de Physique des Solides,

Paris 6, Campus Boucicaut 140 rue de Lourmel,

, France. Tel.: +33-1-43-25-66-40; fax: +33-1-43-

ddress: [email protected] (G. Waysand).

http://www.elsevier.nl/inca/publications/store/5/0/5/

- see front matter r 2003 Published by Elsevier B.V.

/j.nima.2003.11.208

by his elegant experiment on rhenium to demon-strate the X emission fine structure [1]. It was theresult of a long race in low-temperature detection.Registering for LTD-zero, he explained in hisshort letter: ‘‘Presently, I am interested in Joseph-son tunnel detectors for low energy spectro-scopy’’.1 Sandro passed two years ago. This talkis dedicated to his memory.I would like to place our activity in a larger

frame, hence the title of this talk: modestprehistory.To explore the entanglement between particle

physics, astronomy and low temperatures, mystarting point for this sketchy perspective will be1903, just a century ago: in 28min from now (anda few pages ahead for the reader), let us hope thatwe will reach our common LTD birth date: 1983.

1Sandro Vitale to Fran@ois Vanucci , March 14, 1983 (myarchives).

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G. Waysand / Nuclear Instruments and Methods in Physics Research A 520 (2004) 4–10 5

This centennial choice is more than a calendarcoincidence. In 1903, physicists were not many.However, the variety of their interests led to acurious situation which somehow is at the originof the present division of physics in differentfields, each with its own tradition—a divisionwhich we feel so strongly in low-temperaturedetectors.

2. a rays, ‘‘emanations’’yand helium

On June 25, 1903 (thus almost day for day acentury ago), Marie Sklodowska Curie presentedthe findings of her work about a rays in herdoctoral thesis. For her, a rays were alreadyparticles electrically charged and projected at highspeeds2 but nobody was certain that their naturewas independent of the emitting element. A littlecelebration in Marie’s honour, was arranged in theevening by Paul Langevin. Ernest Rutherford wasamong the guests. He was then working in Canadabut temporarily in Paris and anxious to meetMarie Curie. He had good reason. His study of thedeflection of radiation in magnetic fields had notmet with success until he had been sent a stronglyradioactive preparation by the Curies.

a rays were recognized to be emitted by mineralseach time they contained uranium or thorium, buttheir nature was unclear since gaseous radioactive‘‘emanations’’ as they were called by Rutherfordwere also noticed. The most advanced viewtowards the solution of this problem was indeedput forward by Rutherford and Soddy just a yearbefore:

‘‘ythe speculation naturally arises whether thepresence of helium in minerals and its invariableassociation with uranium and thorium, may notbe connected with their radioactivity [2].’’

2 ‘‘It was not till 1900 that Madame Curie threw out the

suggestion that the a-rays, which were stopped by small

thicknesses of metal or glass, proceeding from polonium, might

be of the nature of small particles, projected with great velocity,

but which lost their energy in passing through matter.’’ William

Ramsay (Nobel Lecture for chemistry 1904). Ramsay followed

Rutherford and named ‘‘a rays’’ what we call nowadays a rays.

And again in this year 1903:

‘‘y possibly helium is an ultimate product ofthe disintegration of one of the radioactiveelements, since it is only found in radioactiveminerals.’’

Rutherford based his conviction upon anapproximate measure of e/m=5000 electromag-netic units against 9650 for hydrogen atom (thisone provided by water electrolysis).3 This straight-forward method of identification by a crude massspectrography experiment was at odds with theusual chemical method of analysis of the period:optical spectroscopy.In fact, helium had been discovered by optical

spectroscopy. During the solar eclipse of 1868P.J.C. Janssen, sent to India for observation of thesolar spectrum, noticed a new yellow spectral linein the sun.

‘‘It was suspected by Frankland and Lockyerthat the line was due to hydrogen; but no meanswas found of causing that element to show sucha line. They therefore came to the conclusionthat it must be due to the presence in the solaratmosphere of an element unknown on theearth; and they gave it the name ‘‘helium’’, tosuggest its solar origin. Shortly afterwards,Langlet, working in Cleve’s laboratory, discov-ered helium independently4.’’

Helium at that time was also of interest for thecompletion of the periodic table which was themain interest of Ramsay. Indeed Soddy, the first ofRutherford’s students, left Canada to work withRamsay. According to Ramsay (in his Nobelspeech for chemistry the next year):

‘‘...we at once began to investigate the proper-ties of the radium emanation; for its life is somuch longer than that of the thorium emana-tion (in the proportion 463,000 to 87) that it ispossible to deal with it by ordinary physicalmethods. The emanation from about 60 milli-grams of radium bromide was collected during8 days; it was introduced into a minute

3E. Rutherford, Nobel Lecture.4W. Ramsay, Nobel Lecture.

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measuring tube, and its volume determined; itwas found to be a self-luminous gas, obeyingBoyle’s law; and its volume slowly contractedduring four weeks, until at the end of that timeonly the smallest visible bubble remained,which nevertheless still appeared as a brilliantspeck of light; and on heating the tube whichhad contained the gas, a gas was evolved fromthe walls, possessing three and a half times thevolume of the emanation, which showed thespectrum of helium. It had doubtless beenprojected with a velocity considerable enoughto cause the molecules to imbed themselves inthe glass of tube, from which they were expelledat a red heat.Other experiments showed that it is easy, by

heating a radium salt which has been preparedfor some time, to expel the helium which hasaccumulated; this result has been repeatedlyconfirmed, not only by Soddy and myself, butalso by other observers.’’

Rutherford and Geiger had calculated, on theassumption that the ‘‘a-particle’’ was a heliumatom, that 1 g of radium in equilibrium shouldproduce a volume of 158mm3 of helium per year.With the exception of the recipe to get helium,

these preoccupations were secondary for JamesDewar and Kamerlingh Onnes. They were compe-titors for its liquefaction. Dewar, enjoyed makinga show of presenting during his public lectures atthe Royal Institution the last experiments he hadbuilt. He insisted on using glass, contrary to theadvice of his assistants who were aware thatpresumably at low temperature, radiation heatcannot be neglected. In the end, Dewar’s obsti-nance resulted in helium being liquified for the firsttime, not at the Royal Institution in London but atthe Natuurkunde Laboratory in Leiden.

3. The golden age of physics

The mystery of the emanation was not totallysolved. The ‘‘self-luminous gas’’ was evidently notonly composed of helium. After many years, in thetwenties, it was recognized that the radioactivepart of the emanation was a single element

unknown up to then: radon. But that was alreadythe golden (and still innocent) age of physics.Physicists were not many, but each of them coulddream to get his b #aton de Mar!echal as we say inFrench. A group photograph of smiling physicistsfrom Leningrad, published in a recent biographyof Yacob Frenkel, is a good evidence of this: L.Gurevitch, L. Landau, L. Rosenkevitch, A.Arsenieva, Ya. Frenkel, G. Gamow, M. Man-chinskii, D. Ivanenko and G. Mandel are in frontof a blackboard upon which someone has writtenwith a piece of chalk: ‘‘ANNO QUANTI XXIX’’as if it was engraved above the pediment of atemple [3].Of course, all the achievements of the 1920s and

1930s are our daily tools. But the discovery of theneutron and the positron, the extensive use of thetunnel effect formalism for the description of the aray emission, and the superfluidity of helium are ofextreme importance for what will be low-tempera-ture particle detection.If the late 1920s and 1930s were the golden age

of physics, they were also a dark time for societies.Let us just recall the words of the late NicolasKurti at the banquet talk of LTD4:

‘‘An important event in the history of theClarendon was Hitler’s coming to power inGermany in 1933 which resulted in an influx ofGerman academic refugeesy .’’

Let us also remind ourselves of the fate of thosein a picture taken on the steps of the low-temperature laboratory of Kharkov in the SovietUnion in 1934. Seated on a sunny day in the frontrow are: Shubnikov (shot in 38), Leipunski (jailed,then freed to become a leader of the atomicprogram), Landau (jailed and according to himsaved from a certain death by Kapitza), and finallyKapitza who was denied to return to his MondLaboratory while he was on vacation in the SovietUnion [4].The combination of scientific and political

factors at the end of the 1930s had created adouble movement:

* an internal movement: some physicists faced theemerging division of physics by moving fromone field to another: Kapitza was hired by

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Rutherford mostly for doing nuclear physics,but he moved towards low temperatures,contrary to Kurchatov, who started in semi-conductors but switched to nuclear physics.

* an exile movement, mostly from the thirdReich, Austria and Italy, because of the naziantisemitic laws, which created a deep modifi-cation of the repartition of the scientific work-force within Europe, and between Europe andthe United States.

This scientifico-political context had two im-portant consequences for low-temperature detec-tors:

* the first particle detection at low temperaturewas performed in Oxford by Nicolas Kurtiwhen he brought (without safety precautions!) a1.5 g radium source near his adiabatic demag-netization cryostat, and watched the tempera-ture elevation in order to evaluate its coolingpower. With Simon and Mendelssohn, he hadjust arrived from Breslau (nowadays Wroclaw)a few years before.

* superfluid helium was discovered in Cambridgeby Allen and Misener in spite of Stalin y andin Moscow by Kapitza thanks to Stalin.

However low-temperature as a specific field ofactivity was still in its infancy. There were onlyaround 10 low-temperature laboratories worldwide. The first suggestion of a superconductingbolometer was published on the eve of the war [5].These early developments were almost totallystopped during WWII.

4. A new knot between particle physics, cosmology

and low-temperature physics: superconductivity

After WWII, physics was booming. As a resultof specialization, the borders between fields wereless permeable. Superconductivity, unexpectedly,was to be an exception for a small number ofpeople. The intertwining between nuclear techni-ques and theory leading to the breakthrough of themicroscopic theory, as well as the feedback onparticle physics after Bardeen, Cooper and

Schrieffer had provided the microscopic theory,are still not fully appreciated nowadays.The isotope effect (giving an immediate proof of

the electron–phonon interaction), the concept ofelectron pairing, the utilization of many-bodyproblem techniques, and the later direct measure-ment of the energy gap by tunnel effect are directimportations into condensed matter physics ofproducts, tools and concepts from nuclear andparticle physics.However, in the reverse direction, superconduc-

tivity is the field from which in 1963 BrianJosephson gave to the notion of the phase of thewave function a physical meaning. Particle theo-reticians were happy to describe the vacuum of theStandard Model by analogy with the electromag-netic vacuum inside a superconductor, and moregenerally enjoyed the concepts of broken symme-tries and phase transitions "a la Ginzburg-Landau.In the same way our present description of neutronstar is a byproduct of the microscopic under-standing of superconductivity. Of course, weshould not forget, less mundane but not lessimportant, the numerous utilizations of super-conductivity, either already or potentially in use:transition edge sensors, superheated superconduct-ing grains, tunnel and Josephson junctions andmore generally all the devices in which a spatialmodulation of the order parameter allows thetrapping of quasiparticles. This is evident if nowwe have a look at the main driving force for thedevelopment of low-temperature detectors: obser-vational astronomy.

5. Cosmic microwave background and infrared

astronomy

The bolometer was invented by Langley in 1881and presented in its original publication with someverbosity:

‘‘I had flattered myself with the hope ofsucceeding better than my predecessors. I foundhowever, that though I got results, they were tooobscure to be of any great value, and that sciencepossessed no instrument that could deal success-fully with quantity of radiant heat so minute.

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I have entered into these preliminary remarksas an explanation of the necessity of such aninstrument as that which I have called theBolometer (bolZ,metron), or Actinic Balance,to the cost of whose construction I have meantto devote the sum the Rumsford Committee didme the honor of proposing that the Academyappropriate.Impelled by the pressure of this actual

necessity, I therefore tried to invent somethingmore sensitive than the thermopile, which couldbe at the same time equally accurate, whichshould, I mean, be essentially a ‘‘meter’’ and nota mere indicator of the presence of a feebleradiation. This distinction is a radical one [6].’’

In the late 1950s, Scovil and his associates atBell Labs were building the world’s lowest-noisemicrowave amplifiers, ruby travelling wave ma-sers. These amplifiers were cooled to 4.2K or lessby liquid helium. They were used by Penzias andWilson behind a 20-ft horn-reflector and thereference noise source was also cooled at 4.2K ina separate cryostat. With this combination ofinstruments the spectrum of the cosmic microwavebackground, was discovered and measured at thattime estimated to be a 3K black body spectrum[7]. Since then, the study of the cosmic microwavebackground has been linked to low temperaturedetection.Infrared spectroscopy was a child of this

evolution. Low, one of its pioneers was in 1969reporting on the state of the art of germaniumbolometers. At that time the operating tempera-ture of the typical detector was 2K, with an areaof 1� 1mm2, a focal ratio of f/15 and range ofsensitivity from 7 to 14 mm, a background powerof Q=2� 107W with a thermal conductanceG=10�6W/K, and a noise equivalent power of3� 10�14W/Hz1/2. Contrary to most of us in ourproposals for new funding, Low was apparentlynot an optimist, in his conclusion asking himself:

‘‘The questions arise: ‘‘What of the future?’’, asdetector sensitivity increases through futuredevelopments, can we expect an ever increasingobservational sensitivity? It is clear that theanswer is negative unless the background powercan be reduced...’’

But Low also saw clearly the solution:

‘‘By refrigerating the entire telescope andplacing it in space, it should be possible toextend the observational capability by severalorders of magnitude [8].’’

That has been done.

6. The background of LTD zero: superheated

superconducting grains

Simultaneous with Low’s efforts in infrareddetection, specialists in superconductivity andtheoreticians of phase transitions were puzzled byan irritating issue: Why hysteretic behavior wasnot observed in type I superconductors in spite oftheir first order phase transition in a magneticfield? Of course, it was a minor issue, but theunderstanding of superconductivity has more thanonce been changed drastically by unexpectedexperimental facts. Carefully metallurgically pre-pared pure type I crystals, cylinders, and whiskerswere tested in magnetic fields. If their transitions ina magnetic field were hysteretic, it was almostnegligible. Supercooling was far more easilyobserved than superheating but, in every case,the width of the hysteretic cycle was far from thetheoretical limit of metastability for superheatedand supercooled states.The Orsay group of superconductivity had the

idea to try the same experiment with super-conducting microspheres. The idea of usingmercury came almost immediately, but the veryclever trick was to remember that a long time agomercury salts were prescribed to cure syphiliticchancre. In fact, the ointment was a poisonbecause it also contained metallic mercury, andhad been finally discarded. Orsay at the time beingstill a rural little town, would it be possible that thelocal pharmacy still had the drug? Such was thecase. A small nut of pomade filling the interior of atiny cylindrical coil which was part of a resonantLC circuit was plunged into a liquid helium bathunder reduced pressure. The long awaited resultwas there: superheated and supercooled stateswere immediatly observed as predicted by theory.A conversation between P.G. de Gennes and G.

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Charpak launched the idea of overcoming themetastability barrier by X-irradiation. The path formore mundane experiments was open. In 1975 atDESY, with a 6GeV pure electron beam, a singlechannel transition radiation detector provided adirect proof of transition radiation theory thanksto the wide energy band response of the SSGdetector. Real-time read-out of a single super-heated grain transiting to the normal state wasrealized at the same time. More recently a 16channel device was operated at 100mK wasoperated at CERN [9]. For rare event experiments,one of the drawbacks of SSG detectors is the needof a quiet electromagnetic environment. ZeroGauss chambers are useless since a magnetic fieldis mandatory to get superheated states. Thisdifficulty is now overcome at the LaboratoireSouterrain Bas Bruit de Rustrel-Pays d’Apt (50 kmeast of Avignon). In this low noise undergroundlaboratory below 1500mwe, in a volume of1250m3 without m-metal, the noise level above10Hz is better than 2 fT/Hz1/2, less than a hundredtimes the magnetic noise of your sleeping brain inits cooler phase! (for more details see Ref. [10]).In the early 1980s Raghavan proposed an

experiment to detect solar neutrinos with a low-energy threshold, 128KeV. The target was indiumand besides X’s and g’s the product was tin, bothsuperconductors! Evidently, it had to be large-scale experiment, 4 tons of indium being requiredfor a rate of one event/day. Because of theirmassive nature and easy pixellization, SSG werean evident candidate. To check the interest of thisidea, together with Fran@ois Vanucci, a high-energy physicist from Paris 7, we decided toorganize an informal meeting at Groupe dePhysique des Solides of University Paris-7 to seewhat could be the response of particle physicists tosuch an idea.

7. LTD zero

The small poster for the meeting (a single A4sheet of paper) announced a ‘‘Workshop onMetastable Superconductors in Particle Physics’’on 14–15 April 1983. At the opening of theworkshop, 33 participants had registered and a

little bit more than 20 scientists from a dozen ofsolid state groups and high-energy physics labora-tories actually participated to the meeting.After an introduction to SSG, the state of the

art for the read-out electronics was presented byA. Hrisoho (Orsay), and for transition radiationdetection by D. Perret-Gallix (Annecy). TheJosephson effects were discussed by C. Vanneste(Nice), non-equilibrium superconductivity by N.Perrin (Paris). F. Celani (Frascati) presentedelectronics read-out for tunnel junctions detectorsto introduce indeed a round table about Josephsondevices for SSG. The second day R.S. Raghavan(Bell Labs.) presented his indium solar neutrinocapture proposal and Leo Stodolsky (Max PlanckMunich) described the application of SSG as aneutral current detector for neutrino physics andastronomy. Of course it ended by a round table...after many informal discussions in the caf!essurrounding Jussieu and lively meals taken atnear-by restaurant of cuisine lyonnaise... ). Theoverall budget for all that was less than 1500French francs (230 euros). One outcome of all thisis still alive: LTD meetings.

Acknowledgements

I thank N. Coron (Orsay), V.L. Ginzburg(Lebedev), T.A. Girard (Lisboa), Ch. Glasshauser(Rutgers & Livingston), the late N. Kurti (Ox-ford), J.M. Kantor (Math Paris 7), P. de Marcillac(Orsay), M. Ribeiro Gomes (Lisboa) and JeanMatricon (GPS-Paris 7) co-author of Cold Wars,

A History of Superconductivity (Rutgers UniversityPress, August 2003). They gave to me varioushelps, discussions, interviews and documentations.The mistakes, if any, are mine, of course.

References

[1] F. Gatti, et al., Nature 397 (1999) 137.

[2] E. Rutherford, F. Soddy, Philos. Mag. 4 (1902) 582.

[3] Victor Ya. Frenkel Yakov Ilitch Frenkel, His Work, Life

and Letters, Birkh.auser Verlag, Basel, 1996, p. 141.

[4] Jean Matricon, Georges Waysand, La guerre du Froid,

une histoire de la supraconductivit!e, !editions du Seuil,

Paris, 1994, p. 147 (ISBN 2.02.021792.9 and also in the

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Anglo-American updated version, Cold Wars, A History of

Superconductivity, Rutgers University Press, 2003, p. 93).

[5] A. Goetz, Phys. Rev. 55 (1939) 1270.

[6] S.P. Langley, Proc. Natl. Acad. Arts Sci. 16 (1881) 342.

[7] A.A. Penzias, R.W. Wilson, Astrophys. J. 142 (1965) 419.

[8] F.J. Low, in: W.H. Hogan, T. S. Moss (Eds. ), Cryogenicsz

and Infrared Detection, Proceedings of a Technical

Colloquim on Cryogenics and Infrared Detection Systems,

April 17–18, 1969, Frankfurt-am-Main, West-Germany.

Boston Technical Publishers Inc, Boston, 1969, p. 21.

[9] L.C.L. Yuan, C.P. Chen, C.Y. Huang, S.C. Lee, G.

Waysand, P. Perrier, D. Limagne, V. Jeudy, T. Girard,

Nucl. Instr. and Meth. A 441 (2000) 479.

[10] http://www.Isbb.univ-avignon.fr.

http://www.Isbb.univ-avignon.fr

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A modest prehistory of low-temperature detectors