IS* ^s *1^ o Events and Happenings.. |I LL Sep te 9 Vl , No.^ r in the SLAC Community

1II LC3 I CL\ LI 01 II * * I I I LSeptember 1994, Vol. 5, No. 9

1994 SLAC Summer Science Institute

Looking Out to Astrophysics and Cosmologyby Jill Mhyre

PARTICLE PHYSICISTS havebeen known to joke about the ten-dency of theorists in astrophysicsand cosmology to fly into therealm of science fiction with littlesupportive data. This summer, theparticle physicists stopped joking.In the past couple of years, experi-ments in astrophysics and cosmol-ogy have begun to constrain thetheorists by returning data fasterthan ever before. The 1994 SLACSummer Science Institute, whichtraditionally has focused on issuesin particle physics, paid tribute tothese recent advances in data col-lection, and in the words of confer-ence co-director Lance Dixon,"looked out, so to speak, to theinterface between particle physics,astrophysics, and cosmology."

Professor Michael Turner of theUniversity of Chicago opened theschool with an overview of the BigBang theory of the evolution of theuniverse. This series of three lecturesoutlined the modem view of astro-physics and cosmology, and high-lighted the importance of the rapidexplosion of new experimental datathat has been acquired in recentyears. This data continues to buildsupport of the Standard Model BigBang theory, even as it builds the con-viction that we have seen only a smallfraction of the matter around us.Turner began his lectures with anassertion that "dark matter does

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In keeping with the focus of the 1994 SLAC Summer Science Institute,participants visit nearby Lick observatory.

exist," and this became the centraltheme of the school.

Theorist Joel Primack of UCSanta Cruz compared the currentenvironment in astrophysics to theworld of particle physics in "themid seventies when the StandardModel of particle physics was cre-ated." He said, "We are livingthrough an era like that. Data isstreaming in all the time, and if allthe data were true, then every the-ory would be ruled out. You haveto have strong nerves to livethrough that kind of an era." Headvised physicists to have severalback-up theories in the event ofincriminating evidence againsttheir favorite.

Philip Lubin of UC Santa Barbarapresented one example of the newdata-the search for anisotropies in

the microwave background. Bypointing two antennae to the sky,separated by varying degrees, sci-entists can explore different angu-lar and linear scales of backgroundvariation. The Cosmic BackgroundExperiment (COBE) opened thisfield by scanning differencesbetween angles of about 15degrees, but newer experimentsare looking at much smaller angu-lar scales. Lubin works with theAdvanced Cosmic MicrowaveExplorer (ACME) which measuresanisotropy as a function of fre-quency at angular scales of about 1degree. The results show a signalon the order of 100-200 microKelvins from peak to peak. If thisdata is cosmological and not theresult of a galactic artifact, it

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agrees with the predictions madeby cold dark matter theories.

ACME and other groups collect-ing microwave anisotropy datahave the difficult task of separat-ing the faint cosmological back-ground from signals caused byatmospheric absorption, galacticsynchrotron radiation, inter galac-tic dust, and radio stars. BernardSadoulet talked about the lownoise CCD detectors and signal-processing techniques used toresolve the small signal from astream of detector noise.

Presenting another example ofrecent data collection, CharlesAlcock of Lawrence LivermoreLaboratory described the work ofthe Massive Compact Halo Object(MACHO) group and similar exper-iments called EROS and OGLE, andChristophe Magneville of DAPH-NIA-Saclay, France discussedEROS in more detail. All threegroups are looking for microlens-ing events to provide evidence forbaryonic dark matter in the galac-tic halo. They expect that theremay be many objects, like Jupiter,that are large and compact butwithout enough density to com-bust and shine. When such anobject passes almost in front of astar, gravitational lensing ampli-fies the light from the star in a rec-ognizable way. If compact objectsmake up the galactic halo, then atany given time the predicted num-ber of microlensing events occur-ring is roughly one per millionstars; however, the duration of theevents depends on the mass distri-bution of the objects. To maximizethe probability that they will findan event, they are surveying atotal of 9 million stars every cou-ple of days, and EROS is measur-ing a smaller group of about150,000 stars every ten minutes.Execution of this experiment hasbeen surprisingly fast so far. Pro-posed only seven years ago, EROS,

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MACHO, and OGLEhad published 14candidate events bythe time of the con-ference.

Another speaker,Sanjib Mishra ofHarvard University,touched on bothastronrhvsics andL... _r- --j -_..

particle physics The Summer Inwhen he reviewed dents and postdata that suggests with physiciststhat neutrinos havea mass. Data from undergrounddetectors show that fewer than theexpected number of muon neutri-nos relative to electron neutrinosare produced when cosmic rayshit the earth's atmosphere. Twocollaborations, IMB andKamiokande, now postulate thatsuch a deficit of muon neutrinoscould be explained by the oscilla-tion of muon neutrinos into tauneutrinos, which requires that neu-trinos have a small mass. Thedetectors are not sensitive to thetau flavor of neutrino.

This information is not whatpeople who have proposed the tauneutrino as a component of darkmatter would hope to find. The

stitute provides physics graduate stu-doctorates a chance to meet and talkfrom around the world, as shown above.

oscillation rate indicated by theatmospheric results requires a tauneutrino mass of 0.1 eV, which istoo small compared to the mini-mum of 20 eV required for the tauneutrino to be a useful dark mattercandidate.

A number of the conferencespeakers speculated about thenature of the dark matter of theuniverse. All agreed that darkmatter exists. The movements ofgalaxies and superclusters toapparently empty fields of spacecalled great attractors, the rapidcreation of galaxies, the ratios ofprimordial helium, hydrogen andlithium in the universe, and the

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inflationary theory all require theexistence of huge amounts of darkmatter, but say little about its com-position. Primordial nuclear abun-dances and Big Bangnucleosynthesis plus inflation pre-dict that 90% of the universe iscomposed of non-baryonic parti-cles. Axions, weakly interactingparticles (WIMPS), and the lightestsupersymmetry particles (LSPs) arepossible candidates, as discussedby Mark Srednicki of UC SantaBarbara.

The field of dark matter opensone of the strongest connectionsbetween particle physics and cos-mology. While astrophysicists

search for baryonic dark matter inthe universe with experimentslike MACHO and for cosmologi-cally produced dark matter withterrestrial low-noise solid-statedetectors, as described bySadoulet, particle physicists con-tribute to the search by lookingfor potential dark matter candi-dates in their theories and theircolliders. "The axions," for exam-ple, "were particles invented byparticle physicists to solve thestrong charge-parity problem inparticle physics," said Turner."When you calculate their relicabundance you find out that theyjust happen to close the uni-verse." Dark matter may even be

composed of particles that haveyet to be discovered.

A strong cross-fertilizationbetween theorists and experimen-talists, and between particle physi-cists, cosmologists, andastrophysicists may help open thedoor to the true nature of darkmatter, and to a host of other ques-tions about the universe and theparticles that compose it. TheSLAC Summer Institute on ParticlePhysics turned to astrophysics andcosmology to address the issue ofdark matter from multiple per-spectives, and to promote essentialcommunication between thesewidely disparate but interconnect-ed fields of physics.

Recycled equipment helps local schoolsAS PART of the national effort toimprove math and science educa-tion, SLAC is making donations ofsurplus equipment to public

schools. According to HelenQuinn, Assistant to the Directorfor Education and Public Out-reach, "This is a wonderful oppor-

tunity for SLAC toprovide a commu-nity service. Weare giving teachersthe tools they needto do demonstra-tions and hands-onactivities in theclassroom."

The first dona-tion took placerecently whenBruce Anderson, ahigh-school physicsteacher, collected apower supply touse in his classes atJFK High School inFremont. Andersonplans to use thepower supply toconduct electricityand magnetism

Alan Conrad, left, helps JFK High Sch<Bruce Anderson select equipment frorsalvage warehouse.

strations in at least five of myclasses, and that means over 150students a year will have the bene-fit of this equipment." JFK HighSchool is an urban school with amultiracial student body. Ander-son hopes to attract more interestfrom his female and minority stu-dents with the use of the SLACdonated equipment.

Anderson was formerly anelectrical engineer and has workedclosely with similar equipment.He attended the SLAC workshopon Particles and Interactions,directed by Helen Quinn, in June1994. He plans to incorporate theinformation from the workshopand the use of the equipment intohis lessons.

SLAC employees who have sur-plus equipment that they thinkmight be useful to schools can con-tact Alan Conrad in the warehouse

*at ext. 2329, or P.A. Moore in theEducation Office at ext. 3826.

P.A. Moore

ool teacher demonstrations.n the SLAC "I'll be able to

use these demon-

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Justification for non-competitive procurementsOUR CONTRACT WITH DOErequires SLAC to procure goodsand services using competitiveprocedures to the maximumextent possible. However, on occa-sion, situations arise that makecompetition either impossible ornot feasible. In such situations, it isthe requisitioner's responsibility todocument the reasons why a "solesource" is required. For procure-ments estimated to be below$10,000, a justification is requiredon the Purchase Requisition. Forprocurements estimated to exceed$10,000, a signed "sole source"memorandum is required. The"sole source" memorandum mustinclude the following information:

* A succinct description of therequired supply/servicewith sufficient detail to dis-tinguish the item from anysimilar but non-interchange-able item. This may beaccomplished through refer-ence to special features orpertinent specifications.

*. A description of the circum-stances necessitating otherthan full and open competi-tion. This section shouldmake a clear argument insupport of the restriction ofcompetition.

o* Reference to a particular req-uisition or purchase ordernumber to distinguish theimmediate requirement fromany previous or subsequentpurchase of the same item.

* A statement of attempts tolocate competition, includingmarket surveys. Market sur-veys should include the sur-vey methods (e.g., phonecontacts, publication in jour-nals, and/or posting notices)and the date of the survey.

* Characterization of responses(e.g., "no responses" or"respondents lacked requiredtechnical expertise").

* If other sources offer an item,state clearly the reasons forthe unacceptability of that

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tions of the requirement,state why the offered perfor-mance is not acceptable.

*. Plans for future, follow-onacquisitions, and the steps tobe taken to locate/developcompetitive sources.

*o The sole source justificationmemorandum must besigned by the Requisitioner.

*. The Buyer and the Purchas-ing Officer will review thesole source justificationmemorandum and signifytheir concurrence by signingthe document.

-Alan Saltzberg

Practicing the 3Rs: Reduce, Reuse,KUDOS TO BALBIR GOSAL Laboratory (LBL). LBL saved mon- our "dedicatiand the Mechanical Fabrication ey on waste disposal, and SLAC contributing tDepartment (MFD) for agreeing to received useful chemicals at no mission to prereuse approximately 1,500 pounds cost. Since the chemicals involved ations, procesof metal finishing chemicals sup- were not very expensive, SLAC's As Gosal zplied by Lawrence Berkeley cost saving was small, but the when conside

environment was spared anunnecessary setbacks and LBLsaved approximately $1,000. Thisis a terrific example of a good envi-ronmental practice.

As a result of Gosal's andMFD's accomplishments, at theannual DOE Waste MinimizationConference held last May DOEpresented SLAC with a "Certificateof Appreciation" in recognition of

no need to bediate locale. Ithe list of posto outside oftion.

For additiabout SLAC'sand pollutioiplease contacext. 3401.

Recycleion and leadership ino the Department'sevent pollution in oper-ses and programs."and MFD have shown,ering the 3Rs, there islimited by the imme-

It may pay to expandssible areas for reuseour own organiza-

onal information5 waste minimizationn prevention program,:t Rich Cellamare at

-Melinda Saltzberg

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The Interaction Point © 1994, is published by Information Services of Stanford Linear Accelerator Center. Editor: Evelyn Eldridge-Diaz. StaffWriter: Jill Mhyre. Photographs: Staff. Deadline for articles is the first of every month. Items are published on a space-available basis and are

subject to edit. Submissions may be sent electronically to TIP@SLACVM or by SLAC mail to TIP, MS 68. Phone 926-4128.

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GEM internships complement fellowshipsGRADUATE SCHOOL opens adaunting range of possible careers,so internships have traditionallyhelped students focus their plans.Four masters students in Engineer-ing-Sharon Meadows, OscarMadrigal, Vince Sanchez, andTamara Richardson-came toSLAC this summer to try out thehigh-energy physics field and getsome work experience. They arepart of the Graduate Education forMinority students fellowship pro-gram (GEM).

Tamara Richardson wrote thecomputer code for a new boardthat will transfer information fromthe accelerator to the control room.She is a first-year masters studentin Electrical Engineering from theGeorgia Institute of Technology.Advised by Jeff Olson, Dave Nel-son, and Diane Yeremain, Tamarahad "a pretty good time" aroundSLAC this summer. Originally hop-ing to "combine hardware andsoftware design and electronicsexperience," she worked with JeffOlson to "get some exposure todesigning hardware" and to com-plement her programming. Shewas pleased that her work "will bemeaningful when [she leaves],"given that her advisers in the pro-gram, "are actually going toimplement it." Not only did shegaining valuable work experience,but she provided SLAC withimportant work.

Tamara and the other GEM stu-dents were able to share the Sum-mer Science Program's (SSP) tours,lectures, and trips to Santa Cruz,San Francisco, and Los Angeles,and they lived along side the SSPstudents in the Manzanita trailerson Stanford campus. In spite ofthese close connections to SSP,Tamara and her three GEM coun-terparts were part of a very differ-ent program from SSP.

SSP is a SLAC summer programdesigned to provide an introduc-

GEM participants Sharon Meadows, Tamara Richardson, and VinceSanchez. Not pictured is Oscar Madrigal.

tion to the real world of physicsand engineering to undergraduatestudents. GEM, on the other hand,is a national fellowship programfor graduate students that followsthe recipients from the time theyreceive the award until their grad-uation. In addition to the paidsummer internships, GEM pro-vides a fellowship to fund the stu-dent's graduate school expenses,and to provide an additionalannual stipend, said Brent Hendry,the GEM coordinator at SLAC'sAffirmative Action Office.

SLAC and a group of scienceand engineering companies found-ed GEM in 1976. Since that time,the program has grown into a col-lection of 75 universities and 85industrial companies, saidHendry. While the GEM coalition

provides the fellowships, SLACand the other individual institu-tions select the GEM students, andsponsor them through the summerwith work internships. At SLAC,GEM director an AffirmativeAction Officer SueVon Gee orga-nizes the summer internships inareas in which the students haveexpressed an interest.

The benefits of the program goboth ways. "In exchange for a littlework space and some time from asupervisor," said Hendry, "thedepartments basically get a full-time summer worker." While stu-dents gain valuable workexperience, they provide SLACwith new ideas and fresh energy.

-Jill Mhyre

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offers internships and insights

Shown above are graduates of the 1994 SLAC Summer Science Program. Standing, from left to right, are:James Berry, Clover Huang, Carlos Figueroa, Karen McClenahan, Louis-Gregory Strogler, Jihong Park, JoseLorenzo, Charles Nickel, Sarah Mathis, Tehari Finch, Lynford Goddard, Marisela Reyes, Gabriel Velasquez,Evelyn Aviles-Hernandez, and Kera Bell. Sitting, from left to right, are: Gena Poe, Gabriel Perez-Giz, Kelly Yang,Xuandzung Tran, Waukeshia Jackson, Anna Shapiro, Magdalena Garza, and Ebony Waller.

THE 25TH CLASS of studentsarrived at SLAC for the SummerScience Program (SSP), and accord-ing to Carlos Figueroa, the SSPdirector, the students this yearwere super. Coming from all overthe country, they shared an inter-est in science and engineering thatSLAC worked to promote with thenine-week program which includ-ed lectures, tours of Bay Area labo-ratories and companies, and anindividual project at SLAC.

The SSP program was designedto allow students "to compare per-sonal career objectives with theopportunities available in the com-munity." According to a past stu-dent, "SLAC SSP exposes studentsto the everyday experiences ofpracticing physicists at the timewhen students might be consider-ing careers in physics." The pro-gram targets engineering andphysics students from groups thatare under-represented in the field,including minorities, women, andpeople from rural backgrounds.

SSP Director Carlos Figueroa isproud of the program. He was a

participant in 1986, and had a greatexperience, but says that the pro-gram today is of even higher quali-ty. He credits the work of KarenMcClenahan, the SSP Coordinator,whose organization gives the pro-gram a "more permanent feel." Herefforts were also evident to thisyear's students. Harvard physicsmajor Tehani Finch was impressedthat "the administrators took thetime to get such prominent speak-ers to talk"-speakers from SLAC,Stanford University, and Bay Areaindustrial companies.

Figueroa also credits SLACleadership for making the pro-gram a priority and funding itgenerously, doubling the studentstipend this year to $450 per week.The extra funding made the pro-gram more competitive. With 187applications for 20 spots, the selec-tion committee admitted only twoalternates, so they "basically got[their] first choice of students,"said Figueroa.

But more importantly, the stu-dents in the program seemed hap-py to be at SLAC. Many reported

positive experiences in their inde-pendent projects, especially thosestudents who were working inareas closely related to their courseof study in school. Evelyn Aviles-Hernandez, a computer engineer-ing major from the University ofPuerto Rico, created hypertextprograms to link documents forthe World Wide Web, which sherecognized will be an increasinglyimportant venue for passing infor-mation in the future. "It's been agood experience," said Evelyn, "towork with systems such as UNIXand HTML-a hypertext markuplanguage." She anticipated thather skills will be valuable not onlyin future classes, but also in theworkplace.

Hernandez credited her super-visors, Joan Winters and TonyJohnson, for creating such a valu-able work experience." They giveme suggestions, but let me workmy own way." Several studentsagreed that a good supervisor isthe key to a strong independentproject. About thirty-five SLAC

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physicists and engineers super-vised the students this year. "Theyare dedicated to working withyoung people to challenge them,"said Figueroa, who worked withthe supervisors to establish theinternships.

Burton Richter also recognizedthe important role that the SLACfaculty play in SSP. "The key tothis [program] is the commitmentof the scientists and engineers atthe Laboratory to generate thekind of work assignments that willbenefit the students and to pro-vide the necessary supervision

and mentoring. The full faculty ofthe Laboratory has committeditself to this effort, and with thatcommitment, I believe that theSummer Science Program willmaintain its effectiveness for along time."

Morning lectures and Fridaytours complemented the indepen-dent projects. The group touredLBL, Lawrence Livermore, HewlettPackard, Highland Technologies-a small company with less than 20staff members, Lucas MedicalCenter, and Lick Observatory.They were able to compare large,medium, and small company envi-

ronments to get an idea of the dis-tinct opportunities available ineach.

Finch was "glad to see SLACfunding a program like this." Heexplained that "as an undergrad inscience you have a few caseswhere people will come to youwith an opportunity, but most ofthe time, you are out on your own.It isn't until your third or fourthyear of graduate school that youget a clear picture of the field." SSPgave its students a sneak previewof the physics and engineeringprofessions. -Jill Mhyre

Keeping track of those sun vibrationsONE OUT OF EVERY SEVENAmericans will develop skin can-cer at some point in their lives.Dermatologists diagnose 1 millionnew cases each year, making it themost common form of cancer-three times more common thanbreast or lung cancer.

Dr. Bernard Recht, a practicingdermatologist at Foothill MedicalCenter, taught people what theyneed to know about avoiding skincancer and surviving its harmfuleffects in a New Options for Well-ness presentation on September 9.He emphasized the importance ofrecognizing cancer early to sub-stantially reduce the rate of severescarring and death. People shouldbe aware of their skin and regular-ly look for any changes-darken-ing, bleeding, itching, hurting, andscabbing. The most common skincancers include squamous cell car-cinoma, basal cell carcinoma, andmelanoma.

Fortunately, skin cancer is easyto cure. Today, 95% of skin cancerpatients recover following med-ically approved treatment. Evi-dence comes from Australia wherethe rate of skin cancer has actuallyrisen in the past ten years, but the

Karl Brown's cap protects his skinfrom harmful sun rays.

death rate has been dramaticallyreduced because of an aggressiveeducational campaign that isteaching people to be aware oftheir skin, and to have all changesexamined by a dermatologist.

Many common growths thatare non-cancerous, or benign,remain only on the surface of theskin. Moles are the most commonof a wide variety of harmlessgrowths on the skin. While 25% ofcancers do grow from pre-existingmoles, the other 75% of cancersoriginate as cancer cells. Moles are

not dangerous unless they havechanged, and the removal of allmoles would be an unnecessaryprocedure that would not takeaway the risks for skin cancer.

Skin cancer is related to genet-ics and to the number of blisteringsunburns the individual had as achild. The best way to prevent sundamage is to use sun block with anSPF of 15, and to apply it every fewhours. Higher factors may irritatethe skin because of the high con-centration of chemicals in thelotion, so 15 applied regularly andliberally appears to be the ideal.Because UVB rays burn, and UVArays augment the effect of UVBrays, sunscreens are now availableto block both kinds of solar rays.

Sunburns definitely indicateskin damage, but a tan is a badsign as well. No matter how slow-ly you tanned, if your skin is dark-er than its normal tone, it isdamaged and your body is releas-ing melanin to prevent furtherharm. So remember to use yoursunscreen, and keep an eye onyour skin. Weighing in at about 6pounds, the skin is the largestorgan in your body. Take care of it.

-Jill Mhyre

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SSRL completes FY94 SPEAR runby John Arthur and Ray Isle

THE STANFORD SYNCHROTRONRadiation Laboratory (SSRL) hasjust completed its operation of theSPEAR synchrotron light source forfiscal year 1994. During sevenmonths of running, over 340experiments were performedinvolving more than 560 scientistsfrom around the world. The exper-iments addressed a wide range ofquestions in chemistry, biology,materials science, and physics. Adescription of a particular set offundamental physics experimentsis given below. SPEAR is nowgoing through a busy maintenanceperiod, in preparation for anotherexperimental run starting inDecember.

During two weeks in August, amultinational collaboration per-formed several experiments atSPEAR involving x-ray scatteringfrom nuclear resonances. JohnArthur, Alfred Baron, and StanleyRuby from SSRL were joined byAlexander Chumakov from theFrench ESRF synchrotron facility,Gennadi Smirnov from the Kur-chatov Institute in Moscow, Uwevan Buerck from the TechnicalInstitute in Munich, and GeorgeBrown from the University of Cali-fornia at Santa Cruz.

In typical x-ray scatteringexperiments, the x-rays interactwith the electron shells of the sam-ple atoms. Interactions with thenuclei are thousands of timesweaker, and can be ignored. How-ever, with certain nuclei at particu-lar energies there is a muchstronger reaction, a resonance.Tickle a nuclear resonance with anx-ray at the resonant frequencyand you'll get a much bigger reac-tion than normal, much biggerthan the electron reaction as well.However, the tricky thing aboutnuclear resonances is that they are

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Gennadi Smirnoff, left, Uwe van Buerck, and Alfred Baron, set up the tim-ing electronics for the Mossbauer experiment.

extremely narrow, less than onemicroelectron volt wide, so a veryparticular frequency is required toexcite the resonance. In the pastradioactive sources have beenused to supply these precise fre-quencies, but recent developmentsin x-ray optics have made it possi-ble to use the broadband pulsefrom a synchrotron source toexcite the nuclei. Since the syn-chrotron beam is pulsed, collimat-ed, and polarized, it has distinctadvantages as a means of nuclearexcitation, though special tech-niques are still required to sepa-rate the nuclear scattered signalfrom background scattering byatomic electrons.

In the collaboration's first seriesof experiments, the isotope Fe-57was used. Fe-57 has become the

workhorse for nuclear scatteringstudies using both radioactiveexcitation and synchrotron excita-tion, because of the key roleplayed by iron in materials sci-ence, chemistry, magnetism, andbiology. With the Fe-57 isotope,experiments at a number of syn-chrotron laboratories, includingSSRL, have contributed to anunderstanding of its scatteringproperties, which are far morecomplicated than those of stan-dard atomic x-ray scattering. Therecent work at SSRL continued theexploration of the fundamentalphysics of nuclear scattering withthree experiments: a study ofcoherent and incoherent nuclearscattering in thick stainless steelfoils; a study of interference effects

See SSRL, page 10

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2nd Cooperative R&D Agreement projectSLAC has entered into a specialagreement with two privatecompanies in order to adapt itsx-ray mirror technology forcommercial and industrial use.

The two companies areAdelphi Technology, Inc. ofPalo Alto, California, andn-V1 Arm-; C',- T -T a- s -4 11 r A nt; o 1 "c

U V oUIc yi ltne LLl VlcaLtelialls

Company, Inc. (OSMC) of Troy,Michigan. They have signed aCooperative Research and Devel-opment Agreement with SLAC todevelop a method to reliablydesign and manufacture state-of-the-art multilayer coatingsrequired for high-efficiency x-raymirrors.

This agreement is part of a spe-cial Department of Energy pro-gram designed to encourage the

transfer of technology developedin national laboratories into theprivate sector. DOE is investing$230,000 in the project, while Adel-phi and OSMC are contributing$140,000.

High efficiency x-ray optics areexpected to play a crucial role inemerging technologies that requireprecision imaging and analysis inthe x-ray range. Examples of such

potential applications includeupgrading of the quality ofangiograms (x-ray images ofblood vessels), improved detec-tion of ultra-low concentrationsof impurities on semiconductorwafers, and imaging of astro-nomical x-ray sources.

SLAC has supported pioneer-ing work in the area of multi-

layer x-ray optics in conjunctionwith Stanford's Vapor Phase Syn-thesis Laboratory.

This work and the develop-ment of x-ray beam lines for spe-cialized research applications areongoing activities at the StanfordSynchrotron Radiation Laboratory,now a division of SLAC.

See Development, page 10

Procurement process better serves customersLAST JANUARY, the Team OnProcurement Systems (TOPS) wasformed. Since that time, the com-mittee has met weekly to analyzethe current procurement process,and to make recommendations forits improvement. TOPS supple-mented its own analysis by con-ducting focus group meetingswith approximately 75 employees.These customers of the procure-ment process gave TOPS helpfulopinions and ideas regarding theprocurement process, along withsome war stories. Simultaneously,but separately, another group isgathering user reqirements to rec-ommend a new procurement soft-ware package.

Based on the information TOPSgathered, the group drafted theRequisitioner's Manual to helpSLAC employees use the procure-ment process more effectively, tominimize the number of purchas-ing delays due to inadequately-

written requisitions and poorly-understood procedures, and tohelp requesters work their waythrough the many DOE proce-dures, rules, and regulations. Thefinal version of the manual will bedistributed within two months.

In addition to drafting the Req-uisitioner's Manual, TOPS is ana-lyzing ways to reduce the time ittakes for a completed requisitionto reach the Purchasing Depart-ment. These recommendationswill be given to Jerry Jobe, Associ-ate Director of the Business Ser-vices Division, and to the SLACDirectorate.

TOPS hopes that its careful sug-gestions in the Requisitioner'sManual and recommendations tothe Directorate will improve ser-vice and reduce delays for allSLAC employees who use the pro-curement process.

Jill Mhyre

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Continued from SSRL, page 8

in scattering from fixed and ultra-sonically-vibrated foils; and astudy of the loss of coherence indiffusing systems. Each of theseexperiments examined a differentmechanism by which the coher-ence that is initially induced by thesynchrotron pulse in a large num-ber of sample nuclei can be lostwith time. This work will eventu-ally find applications in the studyof magnetic materials, phase tran-sitions, and chemical reactions.

The goal of the final two experi-ments involved finding resonancesthat had never been observedbefore using synchrotron excita-tion. Two isotopes were used:Kr-83 and Ta-181. In the kryptonexperiment, a Kr-83 gas samplewas used, leading to the firstobservation of synchrotron-excitednuclear fluorescence in a gas. This

experiment showed the feasibilityof using nuclear resonant scatter-ing of synchrotron radiation tostudy the full range of solid-liquid-gas phase transitions. In the finalexperiment, the nuclear resonancein Ta-181 was observed for the firsttime using synchrotron excitation.Because this resonance is extreme-ly narrow, the experimental teamcan claim the nuclear scattered x-ray beam as the most monochro-matic synchrotron light beam everproduced. For this experiment, aspecial eight-hour period of single-bunch operation of SPEAR (withonly one electron bunch in thestorage ring) allowed a measure-ment of the Ta-181 nuclear lifetimeto be performed, showing thewidth of the resonance to be lessthan one nanoelectron volt, andthe corresponding fractional band-width of the scattered beam to be

Continued from Development, page 9

Because of the high energy lev-els involved, highly efficient x-rayoptics are more difficult to designand manufacture than those re-quired for visible light beams. Animportant method for enhancingthe effectiveness of x-ray mirrors,for example, involves the deposi-tion of coatings that are only a fewatomic layers in thickness on a sub-strate. These multilayer coatings, inturn, are typically composed ofrepeated layer-pairs of two differ-ent materials. The number, compo-sitions and thicknesses of thelayer-pairs must be precisely speci-fied for the energy of the beamwith which the mirror will be used.

Under the new agreement thedevelopment of multilayer coat-ings which can be precisely tai-lored to reflect x-ray beams shouldbe significantly extended.

Adelphi, which has concentrat-ed on the development of x-raysources and optics for the past 11

about one part in 1013. By provingthat the techniques and capabilitiesare available to discern these reso-nances, the SSRL team has pavedthe way for future, more compli-cated experiments such as thoseperformed on the Fe-57 isotope.

years, will assist SLAC researchersin translating theoretical designsof multilayer x-ray optics into fab-rication requirements, and in theeventual testing of fabricatedoptics. Its broad range of expertisein x-ray sources and optics isexpected to help define potentialcommercial applications for multi-layer optics.

OSMC, which will fabricate thex-ray devices designed on thisjoint project, is a pioneer in thefield of engineered materials pro-duced by rapid solidification andvacuum deposition processes.

These materials are used in theproduction of bonded permanentmagnets and to reflect x-rays andneutrons in vacuum spectrome-ters, monochromators, x-ray tele-scopes, x-ray microscopes, x-raylithography systems, neutronpolarizers, and neutron wave-guides.

Patrick Lui

10

KeplerComets you say shoot from

nothing?In heaven's name what

other than matter can bematter's mother.

Lorine Niedecker

From the Other Side of the Century:

A New American Poetry 1960-1990

L A

- w

_ -WIN6- ----.. 000"

Quick help responseYOU KNOW ABOUT calling theSCS Help Desk at 926-HELP (ext.4357) for computer needs andproblems, right? Well, now if yourneeds, questions, and problemsare non-critical and if phoningisn't convenient, you can send ane-mail message to

help@slac.stanford.eduIf your problem is critical, contin-ue to call 926-HELP (ext. 4357) andleave an urgent voicemail messageif a person doesn't answer.

The Help Desk will look formessages addressed to

help@slac.stanford.eduhourly during normal workinghours (8 AM to 5 PM, Mondaythrough Friday) and will try toacknowledge receipt of your mes-sage within about two hours. TheHelp Desk staff will get back toyou with an answer or solutionthemselves or route it to a moreappropriate expert.

The reason we suggest that youcall 926-HELP for critical issues isthat the Help Desk can offer amore appropriately quickresponse. Voicemail left on thisnumber for urgent issues arereceived and responded to within20 minutes, 24 hours a day, 7 daysa week.

-Billie Bennett andSandra Crawford

How to stop a phonephreak and protect yourvoice messagesSEVERAL VOICEMAIL users atSLAC have missed getting impor-tant messages when someone witha similar extension accidentallyaccessed the wrong mailbox. On awider scale, toll fraud robs busi-ness and government of about $2.5billion a year.

SLAC's voicemail systemalready enforces several rules tohelp prevent phone fraud:

*. Passwords must be from fourto 16 digits in length.

* A new password may notrepeat any of your five mostrecent passwords.

** Mailboxes are locked aftertwo consecutive invalidlogon attempts.

You can protect your own mes-sages and help protect SLAC's tele-phone system against would-bephone phreaks by selecting a goodvoicemail password and changingit regularly. Beginning in Novem-ber, the system will require usersto change their passwords at leastonce every 90 days. If your pass-word expires, you will not be ableto access your messages or anymailbox commands until youchange the password.

Picking a passwordA "good" password is one that

isn't easy for someone else toguess. It takes an average of 28minutes to break a four-digit codeand six hours to break an eight-digit code. So adding a couple ofdigits to your password canimprove security a lot. Avoidusing passwords that match your

mailbox number or that containstrings of the same digit or stringsof consecutive digits. Also avoidusing passwords containing thecurrent year or information easilyconnected to you such as a name,street address, or department code.

Changing a passwordTo change your password,

either when it expires or sooner:1. Press 84.2. When prompted, enter the

new password, followed by #(pound sign).

3. When prompted, re-enter thenew password, followed by #.

4. When prompted, enter yourold password, followed by #.

Voicemail will confirm thatyour password has been changed.

You can now continue withyour other voicemail activities.

If you enter an invalid pass-word, or the new passwords donot match, you will be taken out ofthe password change procedureand must start the series again.

-Ute Hayes

Departmentspay for ownexpress mailTHE AMOUNT OF SLAC mailsent by Express Mail doubledbetween October 1992 and April1994. Although Express Mail doesprovide next-day delivery to majordomestic markets, it is consider-ably more expensive than firstclass. For example, the cost to maila letter-size piece of domestic mailby first class via the US Postal Ser-vice is $.29. That same piece ofmail will cost $9.95 throughExpress Mail. International mail ismore expensive. As of April 25,the cost of Express Mail has beencharged back to the departmentrequesting that service.

-Jill Mhyre

11

Mary Tropiano, from a photo taken at her retirement dinner.

MARY TROPIANO, who man-aged the SLAC cafeteria undercontract with Mannings during the1970s, died of Alzheimer's diseaseon Monday, August 15. For thoseof you who worked with her in the'70s, Mary was the short, snow-white haired lady who alwayswore a smile and loved everyone.

Mary came to the US from hernative Italy at age 10. She lived inthe Bay Area for 74 years. She issurvived by her daughterAntoinette Mummert of Hayward,her son Nicholas Tropiano of Cas-tro Valley, her sister Emily Nigroof San Leandro, 12 grandchildren,17 great-grandchildren, and manynieces and nephews.

Mary loved her job at SLAC andliked to cater for special occasions.Always up well before dawn tocommute from the East Bay shewould arrive at the cafeteria hoursbefore the breakfast crowd andquite often be there after 5 PM.

Mary gave several of hergrandchildren a chance to earnsome pocket money and experi-ence the job force by bringingthem to work with her. In the win-ter, they just couldn't get overGrandma starting work before the

sun came up and leaving after thesun went down.

Mary was involved with otherpursuits outside of cafeteria man-aging. She was president of theSpanish Ranch Mobile HomesAssociation for several years andloved to play bingo. She also likedto take weekend trips to Reno,where she always did quite wellon the slot machines. But the timethat she was really on "cloudnine" was when she won $12,000playing Keno.

Mary spent her last months in anursing home. Her daughter Annsaid that Mary, even with hermemory failing, continued toremark how badly the kitchenthere was run and how she couldhave run it for less and still hadbetter food.

Mary will be missed by us all!When our paths crossed (severaltimes a year), she always askedthese three questions:

"How are things at SLAC?""How is the food in the cafeteria?"

"How are all the wonderfulpeople?"

Vern Smith

12