BNL 34710 INFORMAL REPORT BNL--34710 DE85 000290 Synchrotron light Source BROOKHAVEN NATIONAL LABORATORY DISTRIBUTION OF THIS DOCUMENT IS UNLIMITED ..M The National Synchrotron Light Source the storage ring vacuum chamber to mirror The NSLS is a national user facility avail- (NSLS) is designed to provide the world's assemblies or apertures where it is further able without charge to users. Proprietary brightest continuous sources of X-ray and channeled down two or three separate work can be done on a full cost recovery UV radiation. It is also the first X-ray facil'ity experimental beam lines. With a total of 44 basis, with the option to retain titleto inven- in the United States dedicated for use as a ports on the two storage rings, this leads to tions resulting from research at the NSLS. synchrotron light source. There is a 750 the possibility of having as many as 90 There are several modes of use of exper- MeV electron storage ring with 16 ports for experiments (1 for each beam line) operat- imental facilities. A large number of beam VUV and IR research and a 2.5 GeV elec- ing simultaneously at the NSLS. lines have been designed and constructed tron storage ring with 28 ports for X-ray Electrons moving along an arc at veloci- by the 30 Participating Research Teams research. ties much less than the speed of light emit (PRTs). PRTs are, for the most part, user Bursts of electrons are first generated by radiation in a dipole pattern. However, at groups from outside BNL with large, long- an electron cjun, accelerated to 70 MeV by a velocities approaching the speed of light, range programs which have been approved linear accelerator (LINAC), and further this radiation is thrown forward in a narrow by the NSLS Program Advisory Commit- accelerated to 750 MeV in the booster syn- cone in the electron's direction of motion tee. The PRTs are given priority for up to chrotron which also groups the electrons much like a laser beam. This concentration 75% of their beam line's operational time. in 5 bunches equally spaced around its 28 of radiation in the forward direction is General users, who may have a less sub- meter circumference. The booster then responsible for the high intrinsic bright- stantial need for the use of the facility, are injects the 750 MeV electron bunches into ness. The radiation is also completely polar- scheduled for both PRT beam lines and for the VUV storage ring or into the X-ray stor- ized, with the electric ve:tor lying in the lines built by NSLS for the general commu- age ring where they are accelerated to their plane of the electron's orbit. The spectrum nity. final 2.5 GeV energy. The booster and stor- of synchrotron radiation extends from the age rings use a common r.f. accelerating infrared up to gamma rays. Since the elec- frequency of 50 MHz. An ultra-high vacuum trons are accelerated in bunches, the result- environment is maintained in each storage ing synchrotron radiation also comes in ring to allow the electrons to circulate for pulses too (less than 10~9 sec in duration). hours at velocities close to the speed of These unique properties ot synchrotron light before being knocked out of their radiation (high brightness, broad and con- orbit by residual gas atoms. tinuous energy range, high polarization Synchrotion radiation is produced when and time structure) have attracted scient- these relativistic electrons are bent in arcs ists from universities, government labora- by the storage ring dipole magnets. The tories and industry. radiation is emitted at a tangent to each point of the arc and travels through ports in DISTRIBUTION OF THIS DOCUMENT IS EXPERIMENTAL BEAM PORTS (16) VUV EXPERIMENTAL STORAGE BEAM PORTS (28) RING RADIATION PATTERN MECHANICAL EQUIPMENT X-RAY STORAGE RING rj j '• X-RAY SHIELD TUNNEL NATIONAL SYNCHROTRON LIGHT SOURCE BROOKHAVEN NATIONAL LABORATORY ENERGY (eV) 1000 100 10 -1- ~r | i i I i i I ' ' 10" - < - /^^ 1j\. - 1016 able (2000-40r)0A) UV source of average <l / 3B PERIOD UNDULATOR The VUV storage ring is 51 meters in cir- / (2 S,,;, = 3.5 mrad) cumference and is designed to operate power in the one watt range. 8 / with a 700 MeV stored electron energy and The X-ray ring is 170 meters in circum- 5) 1015 _ a 1 Ampere beam current. Presently it ference and is designed to operate with a z operaies at 750 MeV, has achieved peak 2.5 GeV stored electron energy and a 500 o Y Ac = 25.3 A ^^< to- _ A ARC SOURCE - / beam current values over 400 mA and a mA beam current. There are 6 straight sec- /I (2e,,2 = 10 mrad) 13 (PI source brightness value of about 4X10 tions available on this ring for insertion _ 2 2 10" photons/sec, mm , mrad ,0.1% bandwidth. devices. The first X-ray insertion device, a / I1 z _ As such, it is the highest brightness VUV 60 KiloGauss 6 pole superconducting wig- UJ // I VUV RING ~ synchrotron radiation source in operation. gler, extends the spectrum into the 100 KeV z - I/ II 30 60 The VUV ring has two 3.2 meter long energy region. 3 III ill ill II 10' straight sections available for special inser- 0.1 10 100 1000 tion devices called wigglers and undula- WAVELENGTH (A) tors. These are periodic magnet structures designed to significantly enhance fne pho- ton intensity and/or brightness o/er speci- fied energy regions. As electrons pass ENERGY (KeV) through these devices, they "wiggle" or 100 10^ 1 0.1 "undulate" and then return to their pre- —pn—i f—i—i f vious storage ring orbit. One of the VUV _ 10" _ 60 30 storage ring straight sections is now used 6 POLE for a 38-period permanent magnet undula- SUPERCON. WIGGLER tor, which has been installed and operated, £ 10' and is now being instrumented for use in the 100-1000A range. It provides for a S E potential brightness increase, compared with a VUV arc source, of approximately a 10' factor of 100. in O During dedicated 300 MeV storage ring operation, the undulator is part of a unique Free Electron Laser designed to be a nar- i- 10'3 - 6 V) row band (5A/A = 10~ ) continuously tune- z X-RAY RING - UJ I- 0.3 0.6 i I I I 0.1 1 10 100 WAVELENGTH (A) When PRT proposals were first solicited in 1979, there was an overwhelming re- sponse from the scientific community which clearly perceived the advantage of having dedicated experimental facilities on high brightness sources of X-ray and UV radiation. The PRT policy has made it pos- sible to simultaneously build up scientific capability in a number of different areas. The facility has a wide range of research equipment available to users for basic and applied studies in condensed matter, sur- face science, photochemistry and photo- physics, lithography, crystallography, small- angle scattering, metallurgy, x-ray micro- scopy, etc. (See Table I) The involvement of scientists from the full spectrum of U.S. institutions is seen in the lists of PRT X-ray and UV beam lines. (Tables Hand III) DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi- bility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer- ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom- mendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of tl.'- United States Government or any agency thereof. _ 1 | TJ m o CO > x cn H 3" 3" C6 o =; x 3 2. 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