SOFCAL (Scintillating Optical Fiber Calorimeter)

SOFCAL was a compact hybrid instrument consisting of a passive emulsion chamber and a thin active ionization calorimeter which was developed to study high energy cosmic ray spectra. The novel component of this instrument was a thin sampling calorimeter that employed small scintillating optical fibers to measure the energy of electromagnetic cascades produced by cosmic rays interacting in the instrument. A planar Cerenkov counter was used to measure the charge of the primary particles.

The energies were estimated from the amount of scintillation light produced at different depths in the calorimeter by the cascades. The scintillation signals were recorded with two image intensified CCD cameras coupled to the scintillating fibers that were arranged as a 10 layer (X,Y) hodoscope. The CCD images were also used to determine the trajectory of each cascade detected.

Balloon launched on: 5/20/1997 at 13:43 utc
Launch site: Scientific Flight Balloon Facility, Fort Sumner, (NM), US  
Balloon launched by: National Scientific Balloon Facility (NSBF)
Balloon manufacturer/size/composition: Zero Pressure Balloon Raven 40L - 1.100.000 m3
Balloon serial number: R39.00-2-107
Flight identification number: 432N
End of flight (L for landing time, W for last contact, otherwise termination time): 5/21/1997 at 14:56 utc
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 26 h
Landing site: 14 miles SW of Congress, Arizona, US
Payload weight: 4500 lbs

• A Scintillating Way to Hunt Cosmic Rays NASA Press release
• NASA Balloon Flights (1989-1998) in NASA Historical Data Book, Vol. VII: NASA Launch Systems, Space Transportation, Human Spaceflight, and Space Science, 1989-1998
• The Scintillating Optical Fiber Calorimeter Instrument Performance (SOFCAL) 26th International Cosmic Ray Conference. August 17-25, 1999. Salt Lake City, Utah, USA