Fixed Target Program - Meson Area
- Historic Photos
- First Magnet Installed
- Meson Lab opens for business with a big order (September, 1972)
- Inside the NAL Meson laboratory (September, 1972)
- Progress continues in NAL Meson Area (July, 1973)
- First streamer chamber collaboration completed here (May, 1976)
- Meson achieves design intensity (April, 1977)
- What has... (October, 1977)
Meson Lab Construction November, 1972
Source: The Village Crier Vol. 3 No. 21, May 27, 1971
The first magnet was recently installed in the NAL Meson Laboratory. On hand to assist in the initial installation are (l. to r.): John Caffey, Jim Humbert, Umer Patel, John Satti and Don Richied
Photo by Tim Fielding, NAL
Source: The Village Crier Vol. 3 No. 34, August 26, 1971
The accelerator provided 200BeV beam on September 18th and 19th for a number of emulsion experiments in the Meson Laboratory. Beam was detected in the P Central building of the Proton Laboratory for the first time at 3:40 a.m. on Friday, September 22nd. 200 BeV beam was again available for experiments at the end of the week.
(Editor's Note: The NAL Meson Laboratory staff drove hard toward completion in 1972. Their efforts to finish were equalled only by the smashing success of the first experiments already carried out there. Art Greene, Physicist on the staff of the Director's Office, and Alan Wehman, Physicist of the Meson Laboratory, contributed the following information on this operational area of NAL.)
On Wednesday morning, September 20, 1972, the NAL Meson Laboratory completed a task difficult to surpass in the future - the completion of nine experiments within a four-day period. Over forty "stacks" of nuclear emulsions were exposed to 200 BeV protons. Physicists from Poland, India, France, Japan, the U.S.S.R., and the United States arrived at NAL for the International Conference with individual emulsion detectors, effectively bringing their experiments in their suitcases. It remained for the visiting physicists and NAL personnel to make the final preparations for the exposures.
Historically, nuclear emulsions were the detection media used for some of the first studies of high energy particle interactions. Due to their light weight and small size, they were frequently used as a detector of cosmic ray interactions in flights of high altitude balloons or satellites. The emulsion material itself is very similar to that used for photographic film, but is produced in sheets up to 1/16" thick and without a backing. A "stack" is formed by several layers of emulsion, bound together and sealed from light. Normally, the stack is exposed to a few hundred thousand particles, some of which interact in the emulsion material producing the interactions of interest to physicists. The emulsion layers are then mounted on glass plates, and undergo an elaborate development process to unveil the traces of particles. Analysis is done exclusively with microscopes, and it takes many months to locate and analyze a few hundred events of interest. Because of this, the primary effort for the experimenter follows the exposure and does not precede it, as with many high energy physics experiments.
This drawing shows the external proton beam path to the Meson Lab Target and the six secondary particle beams (M 1-6), produced from interactions in the target box (MTB). Also, the Main Laboratory Building (MLB) (under construction). Other buildings and enclosures on the line house the beams and the experiments which use the beams. Indicated also are the first experiments utilizing each beam (E-72, E4-I, E-69A, E-96, E-75, E-104)
The Japanese physicists, who participated in the effort under the direction of Dr. Niu of the University of Tokyo, recognized the need for a giant helium bag to reduce interactions of beam protons with air in a 200-foot section of beam line. They immediately set out to construct such an item, utilizing their many years of experience in constructing high altitude helium-filled balloons.
However, it was a clever technique devised by members of the NAL Switchyard Section that provided the essential ingredient. They were successful in shaving off just a few thousand protons from the billions of protons in the circulating beam, and sending them on to the Meson Lab. (Too many particles would over-expose the emulsions and make them useless. Radiation Physics Section and Meson Lab personnel had constructed several monitoring devices to assure that beam could be measured and set for this low intensity.) After a frantic day of last minute preparations, it was decided to go ahead with the initial exposures. The first round of stacks were completed by midnight, and with continued coordination with members of the Acceleration Section, those remaining were exposed by 5:45 a.m. on Wednesday morning, September 20, 1972, just 15 minutes before the end of the available time.
The physicists concerned with the emulsion experiments were: J. Gierula of the Institute of Nuclear Research - Cracow, Poland; David King of the University of Tennessee; P.K. Malhotra of the Tata Institute of Fundamental Research, Bombay, India; G. Thomas of Ball State University, Muncie, Indiana; R. Kaiser and J. Massue of the Center of Nuclear Research -- Strasbourg, France; S. Ozaki and M. Teranaka of Osaka City University, Japan; K. Kui and T. Ogata of Tokyo University, Japan; Jere Lord of the University of Washington; V. Nikitin of Dubna representing M. Tretyakova of the Lebedev Physical Institute, Moscow, U.S.S.R., and Andreas Van Ginneken of NAL.
Following this success, the members of the Meson Laboratory Section continued their preparations for the more complex experiments to come. This included getting ready the 80-ft. long targeting arrangement that allowed six secondary particle beams to share the common target struck by the external proton beam from the accelerator. Preparation was made for operation of the many magnets, collimators, vacuum systems, control systems, etc., of the complex transport systems that carried these particles to experiments placed at various points in the 1,000 ft. long tunnels housing these beam lines. Provisions were made for containment of radiation by a massive overhead covering of soil. Finally, space was provided for the experimenters' equipment in these beam lines, including electrical power systems, water cooling systems, air conditioning systems, and magnets.
The next experiments scheduled for the Meson operations were a quark search and a neutron total cross section measurement. The quark experiment was a hunt for fractionally-charged "quark' particles by physicists from Yale University and Brookhaven National Laboratory, utilizing the normally neutral M4 "KQ" beam as a charged particle path. The neutron total cross section experiment utilized the tunnels of the M3 "neutron" neutral beam and involved physicists from the University of Michigan and Wisconsin.
The nucleus of the Meson Lab group was the old Booster group. Among these were Jim Michelassi, Jan Ryk, Umer Patel, Jim Humbert, Leo Ray, Bud Koecher, Frank Ascolese, Dick Nelson and Joyce Arado. The efforts of Don Richied, Bob Kolar, Bill Lord, Tony Glowacki - among others - contributed to the fine crew of the the Meson Laboratory. Staff physicists of the Meson Laboratory in this effort were Dick Lundy, Klaus Pretzl and Alan Wehman. Valuable contributions in the past toward creation of the Meson Lab were made by a host of others, including Jim Sanford, Lincoln Read, Ed Bleser, Dick Orr, Dick Carrigan, Dave Carey, Dave Eartly, and Roland Juhala - just to single out a heroic few. Groups outside the Section making valuable contributions were the Controls Group under Bob Daniels, the Alignment Group under Bill Testin, and DUSAF represented by Tom Pawlak.
Assisting with the emulsion experiments were Lou Voyvodic (Experiment Coordinator) and Jim Hoover of the Neutrino Lab; Bleser, Gene Fisk, Joe Gomilar, Jack McCarthy, Robert Oberholtzer, Les Oleksiuk, and Claus Rode of the Switchyard Section; Bob Horbis, Leonard Indykiewicz, Randy Ingamells, Kolar, Lundy, Pretzl, Richied, and Dimetrios Zafiropoulos.
Don Richied and John Caffey inspecting a sweeping magnet in the M-3 line. The magnet in the pit is for the M-4 line, 4-feet below the ground level
(L to R) R. Lundy, K. Pretzl, R. Kolar, L. Voyvodic at the location of the emulsion experiments
Umer Patel (Left) and Frank Ascolese at neutron detector of the neutron total cross section experiment
|(Photos by Tim Fielding)|
Source: The Village Crier Vol. 4 No. 31, September 28, 1972
An aerial view of the Detector Building and some of the experimental lines of the NAL Meson Area. Since the photo was taken in April, 1973, enclosures, the same as over the M6 Line, were completed over the Ml Line and the M2 Line (the two lower rectangles extending from the building). Main accelerator is to the left (southwest) of the building
The Meson Area recently finished "hosting" the Brookhaven-Yale quark search at NAL, one of the first searches for particles that were predicted by theories for some years and required the high energies of the NAL accelerator for experimental verification. The quark, for instance, was proposed in a conjecture by Murray Gell-Mann (who was also a member of the NAL Program Advisory Committee in 1973) and Yuval Ne'emen in 1961. According to their ideas, a particle with a fractional electrical charge, named the "quark" by Gell-Mann, could be used to understand the known sub-atomic particles such as mesons and protons, by considering these particles to be built up from quarks.
installing target load on the Meson target train
The experimental plans for Experiment #72 matched the plans to activate the M-4 Line of the Meson Section. Experimenters from the Brookhaven-Yale University collaboration installed their equipment on the M-4 Line and ran for 500 hours until completion on June 11. No quark was found in this first run, but a modest effort by the group continued. "They demonstrated again what has been found before - a measure of the rareness of quarks," according to Richard Lundy, head of the NAL Meson Section.
Experiment 75, another quark search, began in the Meson Area. Taiji Yamanouchi of NAL's Neutrino Section, was spokesman for the group, in collaboration with Tom Nash of NAL's Proton Section; David Nease, Cornell graduate student, and John Sculli of New York University. This group took data in May for the first phase of their plan; the second phase was completed in August, 1973.
Equipment and enclosure of the Single Arm Spectrometer in the M6 Line
R. Gustafson (Experiment 4A) at liquid hydrogen target in the M3 Line
The Meson Area provided locations for six relatively fixed beam lines, using beams of secondary particles, particles produced following the collision of the proton beam from the Main Accelerator with a metal target on the Meson Target train. These particles were typically mesons (medium-mass particles), although one of the six lines was a neutron particle beam and another a diffracted proton beam. Beam from the accelerator entered an 80 ft. Meson Target Box containing the tungsten target mounted in the array of equipment located on a 3-car target train. The six lines began at the target box and transported beams some 1400 ft. farther down the line to the Detector Building, each beam with certain characteristics. The six lines and their status in July 1973 was:
A charged particle beam line stressing high intensity, with a 220 BeV energy limit at present, and provision for Cerenkov counters which tag the particles. Five experiments were approved for this line, plus one test.
A charged particle beam of diffracted protons swept from the M3 neutral beam line and recombined to yield high momentum. Seven experiments were approved for this line including the NAL quark search.
This line is a neutral beam from which all charged particles were removed. The neutron particles here were used by four experiments already approved.
Also a neutral beam line, extending at an angle downward from the horizontal position of the other Meson Lines. M4 passed under the detector building into a tunnel on the north side of the building where experiments were installed. The large initial angle resulted in higher relative production of neutral kaon and neutron particles. Two experiments were scheduled here.
A test line for the present.
Divided into two branches - east and west. One utilized a single spectrometer, the other scattering equipment, both studied the effects of the secondary particles striking targets in the Meson Detector Building. The Single Arm Spectrometer was housed in a metal enclosure extending 600 feet from the north end of the Detector Building. Three experiments were approved for the M6 Line.
Headquarters for the Meson Area, located 1400 feet from the target, was the Detector Building. The arched roof of the 250' X 160' building was formed by C-shaped corrugated steel elements placed on one side and assembled in rows to form a striking scalloped effect on the exterior. The Detector Building housed controls for the main components of the Meson Lines as well as administrative offices, a 20-ton crane spanning the entire length of the building, and a vast array of experimental set-ups.
Administration of the Meson Section was headed by Dick Lundy, with assistance in liaison from Frank Ascolese, and Joyce Arado as secretary. Liaison physicists in the section were S. Ecklund, H. Haggarty, P. Koehler, E. Malamud, and A. Wehmann. The operations group was headed by R. Trendler. Engineering work was handled by R. Niemann, with Marie Nelson as secretary. The installation group was led by R. Kolar. Components for the Meson Lines were built by a group headed by J. Michelassi as supervisor. Beam line and experimental design was the work of T. Glowacki. U. Patel, and J. Satti.
Source: The Village Crier Vol. 5 No. 25, July 12, 1973
BP3 magnet used in E-86 and E-416
One of the international collaborations so common at Fermilab has completed a successful run in the Meson Area. Scientists from the University of Washington at Seattle, the University of California at Davis, and the Laboratoire de l'Accelerateur Lineaire at Orsay, France came together in the Midwestern United States, bringing with them years of collaboration and joint studies. They recently completed two of the first streamer chamber experiments at Fermilab energies, E-416 and E-86.
The experimenters included T. Burnett, V. Cook, S. Csorna, A. Jonckheere, R. Kenyon, H. J. Lubatti, K. Moriyasu, and B. Robinson of the University of Washington; J. Klems, W. Ko, R. Lander, D. Pellett, of the University of California, Davis; J. Colas, D. Fournier, P. Rancon, and J. J. Veillet of the Laboratoire de l'Accelerateur Lineaire, Orsay. The late Prof. A. Lagarrigue of Orsay did much to make the collaboration possible.
have finished winding 101 turns on the iron in an all-night session
The same magnet that is such an important part of the experiment had previously served the experimenters at CERN, in Geneva, Switzerland, from 1961 to 1964. It was at Orsay that the present collaborators first became interested in doing an experiment to study the diffractive dissociation of particles. In 1970 they submitted a proposal to continue at Fermilab the research they had begun in Europe. The French scientists also furnished the cameras for the experimental apparatus. The California experimenters on E-416 furnished the scintillators for the muon telescope and a calorimeter. The University of Washington provided the experiment's other hardware.
changes in the Marx generator box
The experiments use the first streamer chamber in a major experiment at Fermilab. The streamer chamber, a vessel 1m x 50 cm x 30 cm (about the size of a trunk) is filled with neon gas, then mounted inside the magnet. A beam of particles comes through the beam pipe of the M-l beam line. For E-416 a 5 cm lucite target was placed at the upstream end of the streamer chamber. A carefully-calculated combination of electronic devices ignores unwanted events but permits up to five cameras with shutters continually open, to be triggered by "good" events visible through the glass side of the streamer chamber. A good event results in a picture similar to a bubble chamber track picture. The film is analyzed on automatic scanning devices at both the University of Washington and at Orsay, France.
Photo of an event in the streamer chamber triggered by two muons, illustrating the Vee of a neutral strange particle decay. E-416 (.completed in July, 1975) was searching for correlations of dimuons with neutral strange particles in pi minus interactions
E-416 searched for "charmed" particles by looking in the streamer chamber for neutral strange particles produced in association with muons. "Charm" may be a property similar to strangeness. Charm has received a great deal of attention since the discoveries in the neutrino beam at Fermilab and the discovery of the J/psi. Theorists at Fermilab and elsewhere have suggested that charmed particles would occasionally decay into a muon plus a strange particle and a neutrino. To see this decay, a large muon detector, consisting of magnetized iron absorber, provided by Fermilab, plus scintillators and spark chambers, was placed behind the streamer chamber to signal whenever a muon was produced. A picture was then taken of that interaction in the streamer chamber.
The streamer chamber pictures were scanned and the number of "Vees" (neutral strange particles look like the letter V in a streamer chamber) associated with muons were counted. This number was compared with the number of Vees ordinarily produced without a muon. Any excess of the Vee-plus-muons events could be an indication of possible charmed particles.
"Charm, unfortunately, turned out to be even more elusive than we thought," reports Henry Lubatti of the University of Washington, spokesman for E-416. "We did not find any excess in the number of Vees produced with muons over that ordinarily produced without muons."
The experiment, however, did see a handful of psi/J events, and they have submitted a proposal to use their streamer chamber to further study the details of how psis are produced, still unknown to particle physicists.
E-416's search for charm was a diversion from E-86, which studied the diffractive dissociation of pions on helium nucleus targets. For E-86 the streamer chamber was filled with helium gas which acted as the target and also produced streamers for the charged tracks. The sensitivity of this experiment can be inferred from the fact that bags of helium gas are often used in experiments as a cheap substitute for vacuum pipes! The experimenters returned to E-86 after the charm search and these data are now being analyzed.
"E-86 and E-416 have demonstrated how streamer chambers can effectively bridge the gap between bubble chambers and pure electronic detectors," Dr. Lubatti says. "Streamer chambers can operate with high intensity beams and can be triggered like counter experiments. Thus, they are uniquely suited for detecting very rare events and showing every charged particle, as well as many neutral particles, from the interactions."
Source: The Village Crier Vol. 8 No. 21, May 27, 1976
The Meson Experimental Area achieved an intensity of 10(10) protons per pulse on the M-2 beam line for the first time on Friday morning, April 15. The success follows several weeks of intense efforts in the Area to achieve this design intensity. Additional Shielding and a new monitoring system were installed. The Switchyard group assisted in the test.
Looking past on six years of waiting for the diffracted proton beam, one of its designers, Rich Orr, comments, "Linc Read and I stated in the 'Meson Laboratory Preliminary Design Report' in March 1971 that the M2 Diffracted Proton Beam would deliver 'an intensity of about 1010 diffracted protons / pulse.'
"Tim Toohig and the Meson Lab people have finally made honest men of us. At this intensity, the beam will be able to feed a much wider range of experiments than was previously possible."
Source: The Village Crier Vol. 9 No. 16, April 21, 1977
... 34 legs, a stainless steel body 50 feet long and does high-energy physics? It's a helium transfer line that was carried .3 miles in about 10 minutes from Lab 8 to Lab 6 in the Village. Seventeen volunteers--16 men and a woman--put their shoulders (and legs) to the task on one sunny afternoon recently.
Meson Lab's technical group had constructed the line, a five-inch diameter pipe, in Lab 8. It was designed to be used in conjunction with three energy doubler/saver magnets in Lab 6. Project Leader Umer Patel (Meson) reported that Chuck Grozis and Roger Deneen (Res. Services) had helped design and construct the line; Leo Ray and John Caffey (Meson) did much of the fabrication.
Chuck Brown (Meson) added that the goal of the project is to create a tri-magnet module that will be self-contained, easily controlled and serviced by operating crews in the Meson Area. Another main feature will be interchangeability for existing strings of main ring magnets in Meson tunnels. The line will run from magnets in the tunnels to a refrigerator in a small building outside the Meson shielding berm.
(L-R): Diane Garcia, John Williams, Chuck Grozis, Leo Ray, Clarence Rogers, Roger Deneen, Steve Anderson, Jim Peifer, Jim Seeman, Ray Carra, Wayne Waldon, Calvin Grayson, Bud Koecher, John Caffey, Lee Mapalo, Bob Jensen, Bob Maly
Source: The Village Crier Vol. 9 No. 41, October 20, 1977
Painting the Meson building, 1982