Preparations - Intensive work on preparation with the reservation of a picnic shelter in May continued with a June 21 trip to Mt. Mitchell to verify that the picnic shelter we had reserved really was suitable for our experiment. Mt. Mitchell still had banks of Rhododendron in bloom, does have the high altitude we need, and treated us to the sight of a young bear scampering across the Blue Ridge Parkway on our way home. Our picnic shelter was superbly suited to our purposes. It even had protective walls, but it was down at least the equivalent of one story from the parking lot and it had no electrical power. We would need to bring a suitable generator and a dolly to help transport our equipment, including the generator and 500 pounds of concrete bricks, down to the shelter.
Med Webster's garage has a roof more like the picnic shelter than the thick concrete floors and roof of the physics building, so preparations were done in his garage. Bill and Med tested the generator (courtesy of Prof. Mendenhall) on a rainy July 4th. It provided satisfactory power - for four and a half hours on a gallon of gasoline - for both units and a lamp. A curve of counting rate vs. the number of bricks in a telescope was taken to show that there was a "soft component" which could be greatly reduced by two bricks (8 cm) and the counters were left recording high statistics runs for the low altitude data which would be compared with data taken on Mt. Mitchell.
Monday Jul 8 at Med Webster's house. (directions )
8:30 - 9:00 coffee, informal discussion
9;00-10:00 MSW - background on relativity, time dilation, cosmic rays, and physicists with Jewish connections in late 30s early 40s. Distribute copies of Rossi's historical note on Mt. Evans experiment. Questions: 1) How do we know the speed of Cosmic Ray Muons? 2) How do we know the average or half lifetime of a muon at rest? 3) Why do we put in about a meter of concrete for the mountain run? 4) What numbers do we compare from the different altitude experiments? 5) Why record triple coincidences as well as 4-folds? 5) Why do we record data at fixed intervals (1 hr?) rather than just at the start and end of day? If we record 10,000 counts in two hours, what would we quote as the hourly rate and its uncertainty?
10-10:15 break, coffee, cookies, and even coke (but only if you bring it).
10:15-11 1) Anderson - counters in muon week 2) Berry - Europe trip which almost included CERN 3) Gigante - CR flux in the Smokies, trip with Cincinnati group.
11 Bill Gabella - What is new at CERN?
Noon Lunch - go to Green Hills if you did not bring one.
1:30 MSW Reimbursement for travel, Signing time sheet, Parking passes for Friday. Update personnel data.
Where is the Carolina Country Inn (Burnsville, NC)? Who is driving and who is taking parts of counters, bricks, hand truck, generator?
Systematics of data recording, both disk files and manual recording.
Record the data for the sets which are running in the basement. Turn off and disassemble the two units. Apportion parts to cars which will take the parts and people to Mt. Mitchell.
Tues Jul 9 Drive to motel in Burnsville NC
Wednesday July 10 was clearly the highlight of our week. It started with an early breakfast in Burnsville. We arrived at our picnic shelter shortly after 8 and began packing our apparatus, bricks, and generator down the hill. Willing hands made a quick job of setting up. Setting the generator below and outside cut noise and exhaust fumes in the shelter but required a tent. Meaghan making a check. Kim and Terry checking out maps of local trails. Med in a discussion with Kim and Diana. Bill H. deep thoughts interrupted for photo.
Hikes on the beautiful trails were a good break from watching computer screens. The top of the mountain was about a hundred feet above our site and the trail to the peak provided a good overview of the area. That is Diana's car in about the middle of the picture and our shelter roof is just visible through the trees near it. They call these the Smokey Mountains, but those wisps are cold, damp clouds. The very top of Mt. Mitchell has a viewing area built up above the trees and a brass disk in the floor to mark the peak and state the claim that this is the highest point east of the Mississippi.
Our only equipment problem was an intermittent connection in the plugs which supplied power to the bases of the photomultipliers in two of the detectors for our 23 brick counter. These showed up as very low singles counting rate on the scaler. A good connection could be reestablished by twisting the cable connector where it plugged in near the base of the tube. But the tube was dead for several minutes before the evidence showed on the scalers screen and it took a few minutes more to reset the connector. Despite paying close attention, here by Diana and Kim and Diana and Jim, we lost about an hour of data time because of this problem.
An unexpected outreach opportunity was the interest showed by about a dozen groups visiting the park and curious about what we were doing. Kim became our public relations officer and explained about muons and time dilation to a young couple and to two teachers who stopped by. Everyone appears happy and pleased with our days work on Mt. Mitchell as we pose for a final picture before packing our muon counters back into cars at the end of the day.
Thursday Jul 11 Drive back home.
Fri July 12 8:30 Assemble in Vanderbilt Stevenson Science Center 6322. If you have brought apparatus back, drive to loading dock where someone with a cart will help you unload. Then go park and come to the meeting in SC 6322.
Just in time to help with the unloading,we were joined by Spencer Pasero who is reviewing our Quarknet program.
Our main objective is to calculate the muon rates in Nashville and on the mountain (with errors) and to answer the question: Are these rates in Nashville and on the mountain consistent with a particle which is moving at approximately the speed of light and which has a (laboratory frame of reference) lifetime of 2.2 microsec? That is a 1/e lifetime, the half life is 1.52 microsec. To answer this question and to clarify the loss of muons which do not have sufficient energy to penetrate the entire air column, we split into three groups with a specific assignment for each.
But first Med offered an amusing and very timely diversion on moving particle physics size instruments. James Anderson and Bill Hunnicutt went to the Ferimlab workshop two weeks later and were there to welcome the g-2 ring to Fermilab. Bill H snapped some great pictures of event: Coming down the drive viewed through one of the lower windows of Wilson Hall. It really is there. Look in the second from right of the lowest row of horizontal rectangular windows. Closeup of ring on trailer , and parked (temporarily) in front of Wilson Hall. Thanks for the pics, Bill.
At the end of the day each group presented its work and Bill and Med have edited the contributions into a paper which presents very convincing proof that time dilation is needed to account for the very small decrease of the muon flux in Nashville as compared to Mt. Mitchell.