Five cool things an ‘atom smasher’ can do

Santa Fe New Mexican - - HEALTH & SCIENCE - By Bruce Carl­sten

Early in the 20th cen­tury, sci­en­tists be­gan to un­ravel the atom’s in­ner work­ings, dis­cov­er­ing tiny par­ti­cles like pro­tons, neu­trons and elec­trons. To bet­ter un­der­stand how these par­ti­cles work, pi­o­neer sci­en­tists de­vel­oped and built “atom smash­ers,” huge ma­chines that ac­cel­er­ate par­ti­cles to near the speed of light and crash them into each other at ex­tremely high en­er­gies.

To­day, ac­cel­er­a­tors are com­mon in var­i­ous places, from hos­pi­tals, where they cre­ate par­ti­cles for med­i­cal imag­ing and treat­ing dis­eases, to world-class re­search lab­o­ra­to­ries, where they con­tinue to ex­plore how the uni­verse works at the small­est scale.

Los Alamos Na­tional Lab­o­ra­tory has sev­eral ac­cel­er­a­tors pep­pered through­out its 43 square miles. By far its largest is the ac­cel­er­a­tor at the Los Alamos Neu­tron Sci­ence Cen­ter (LANSCE). The most pow­er­ful lin­ear ac­cel­er­a­tor in the world when it opened in 1972, LANSCE speeds pro­tons, one of the ba­sic build­ing blocks of atoms, to 84 per­cent the speed of light and en­er­gies as high as 800 mil­lion elec­tron volts.

The pro­tons trav­el­ing down the ac­cel­er­a­tor are mov­ing a tril­lion times faster than a mos­quito trav­el­ing down the same ac­cel­er­a­tor — that’s a pretty big deal. Pro­tons are very light, so each one car­ries very lit­tle ac­tual en­ergy, but there are so many that to­gether they de­liver nearly a megawatt, one mil­lion watts, of av­er­age power to tar­gets at the end of the ac­cel­er­a­tor.

Sci­en­tists pri­mar­ily use big ac­cel­er­a­tors to con­duct ba­sic re­search into the fun­da­men­tal mys­ter­ies of the uni­verse, but work done with these ma­chines also im­proves our daily lives. The fol­low­ing are five cool things pro­duced to­day at ac­cel­er­a­tors around the world.

1. Cool­ing down neu­trons to study na­ture’s hid­den se­crets

Con­nected to the LANSCE ac­cel­er­a­tor is the Ul­tra­cold Neu­tron fa­cil­ity, which uses the ac­cel­er­a­tor to pro­duce high­en­ergy neu­trons. Along with pro­tons, neu­trons make up an atom’s core, the nu­cleus. Neu­trons do not have an elec­tric charge—they are neu­tral. Sci­en­tists use a heavy form of hy­dro­gen to slow neu­trons pro­duced by LANSCE by one mil­lion bil­lion fold to only a few me­ters per sec­ond and then trap the slow neu­trons in a mag­netic “bath­tub.”

By slow­ing down neu­trons, sci­en­tists can make un­prece­dented mea­sure­ments and con­duct ex­per­i­ments about their prop­er­ties, like how long a neu­tron takes to de­cay. In­deed, Los Alamos sci­en­tists have cal­cu­lated the most pre­cise “life­span” of the neu­tron. Such mea­sure­ments and ex­per­i­ments could help an­swer ques­tions as­so­ci­ated with the fun­da­men­tal con­stants of na­ture, such as how the uni­verse was orig­i­nally formed.

2. Pro­duc­ing med­i­cal iso­topes to di­ag­nose and treat can­cer

Ac­cel­er­a­tors make ra­dioiso­topes, which play a key role in var­i­ous ap­pli­ca­tions, one be­ing nu­clear medicine. A ra­dioiso­tope emits ra­di­a­tion that can be used to di­ag­nose and treat var­i­ous dis­eases. LANSCE makes var­i­ous iso­topes, in­clud­ing one used to treat ap­prox­i­mately 30,000 car­diac pa­tients per month—it’s that com­mon. Los Alamos is trans­fer­ring work on med­i­cal-imag­ing iso­topes to in­dus­try while sci­en­tists shift their at­ten­tion to ad­vanced re­search to push the use of ra­dioiso­topes for med­i­cal ap­pli­ca­tions even fur­ther. For ex­am­ple, iso­topes are be­ing de­vel­oped to bat­tle can­cer by de­stroy­ing tar­geted cells in tu­mors.

3. De­sign­ing new ma­te­ri­als

Ac­cel­er­a­tors are used to make ma­te­ri­als stronger through ion im­plan­ta­tion. This process uses an ac­cel­er­a­tor to smash elec­tri­cally charged el­e­ments known as ions into a solid tar­get, thus chang­ing the tar­get’s phys­i­cal, chem­i­cal or elec­tri­cal prop­er­ties. Ac­cel­er­a­tors can also be used to de­velop de­tec­tors for non­de­struc­tive test­ing, which can be used, for ex­am­ple, to in­spect bridges to see if they have minute cracks or other im­per­fec­tions that in time could lead to dis­as­ter. LANSCE in­stru­ments can also char­ac­ter­ize man­u­fac­tur­ing flaws non­de­struc­tively in ma­te­ri­als such as tung­sten.

Physi­cists use elec­tron ac­cel­er­a­tors to cre­ate high-en­ergy X-rays ca­pa­ble of pen­e­trat­ing the very na­ture of mat­ter. With these in­cred­i­ble light sources, it is now pos­si­ble to make movies of mol­e­cules as they move and flex and take still images of chem­i­cal re­ac­tions. That lets sci­en­tists study them at pre­cise mo­ments in time and ex­am­ine the very struc­ture of mat­ter so re­searchers can, for ex­am­ple, find ways to make ma­te­ri­als stronger, more flex­i­ble or more dam­age re­sis­tant.

4. Cre­at­ing new nu­clear re­ac­tors and fu­els

Al­though sci­en­tists have made in­roads with al­ter­na­tive en­ergy sources like wind and so­lar, nu­clear en­ergy re­mains a vi­able op­tion for en­ergy pro­duc­tion. LANSCE sci­en­tists, work­ing through the Depart­ment of En­ergy’s Ad­vanced Fuel Cy­cle Ini­tia­tive, are de­vel­op­ing new classes of nu­clear re­ac­tors and new types of fu­els. Us­ing in­stru­ments at­tached to LANSCE, sci­en­tists can char­ac­ter­ize nu­clear fu­els and find ways to make them safer and cleaner. Safe and cleaner re­ac­tors and fuel will help de­crease Amer­ica’s pro­duc­tion of green­house gases. Also, sci­en­tists are de­sign­ing new re­ac­tors based on fu­els that can­not be used in nu­clear weapons, greatly re­duc­ing the chances of the fuel be­ing stolen for its pos­si­ble use in nu­clear ter­ror­ism.

5. Tak­ing ex­otic images

In 1998, pa­le­on­tol­o­gists dis­cov­ered a 74-mil­lion-year-old fos­sil of a dis­tant rel­a­tive of a tyran­nosaur. Al­though the out­side of the skull looks im­pres­sive, what it looked like from the in­side proved elu­sive, as it was a chunk of solid rock. Con­ven­tional X-ray ma­chines could not pen­e­trate it.

The New Mex­ico Mu­seum of Na­tional His­tory and Sci­ence brought the skull to Los Alamos, where sci­en­tists used the LANSCE ac­cel­er­a­tor to cre­ate a beam of high-en­ergy neu­trons ca­pa­ble of go­ing where X-rays can’t. The re­sul­tant scan of the skull re­vealed startling in­ter­nal de­tails, such as unerupted teeth, brain and si­nus cav­i­ties, the in­ter­nal struc­ture of some small bones and even path­ways where nerves and blood ves­sels once tra­versed to give the tyran­nosaur life.

Bruce Carl­sten is a Los Alamos Na­tional Lab­o­ra­tory Fel­low and a se­nior re­search and de­vel­op­ment en­gi­neer work­ing in phys­i­cal sciences.

LOS ALAMOS NA­TIONAL LAB­O­RA­TORY PHOTO

In­jec­tors at the Los Alamos Neu­tron Sci­ence Cen­ter cre­ate the high-en­ergy par­ti­cles for the beam used to ex­plore the ba­sic prop­er­ties of mat­ter.

Sci­ence on the Hill

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