Avalanche Photodiode Research Group
Physics Department
Brookhaven National Laboratory

Photographs of planar avalanche photodiodes (APDs) fabricated at RMD

Wide angle photo of BNL APD test lab

Development of Very Large, High Gain APDs for Particle Physics

APD Group Members:

Mary Bishai , Nicolo Cartiglia , Milind Diwan,

Mark Dierckxsens , Laurence Littenberg , Mike Sivertz , Brett Viren

 Email the BNL APD group

A Photomultiplier Tube

For several decades, photomultiplier tubes (PMT) have been the key technology for sensing light for most particle physics research operations. Despite their success, PMTs have a number of limitations: (1) large PMTs are bulky and expensive (2) PMTs have limited sensitivity over a small wavelength band (3) PMTs have low quantum efficiency (4) PMTs cannot operate under high magnetic fields. To address the photo-sensing needs of the next generation of high energy, nuclear and astro-physics experiments, BNL has embarked on a research program into alternative designs of large area photosensors. A promising replacement for the PMT is the silicon avalanche photodiode (APD). APDs have many applications as generic photodectors in several science and engineering fields, including opto-electronics and medical imaging.

The BNL photodetector research group has recently been awarded phase II of a DOE grant to develop very large area APDs with performance suitable for high energy physics applications. The research is to be carried out in partnership with Radiation Monitoring Devices Inc. in Boston, MA.

There are several potential applications for very large area APDs that are of particular interest to the BNL group. In particular, the development of technologies for the next generation of very large, megaton-size, neutrino detectors to be used in very long baseline neutrino oscillation experiments .

PMTs lining the SuperKamiokande Detector. The detector is being filled with water.

The SuperKamiokande neutrino detector in Japan is one of the most successful of the current generation of neutrino detectors. SuperK is a 50 kTon water detector instrumented with PMTs that detects neutrinos from the sun and produced in the atmosphere. High energy charged particles, such as electrons and muons produced from the interaction of neutrinos in the water, produce a cone of Cherenkov light in the detector with wavelengths ranging from UV to the visible.

Rings of Cherenkov light detected by PMTs in the proposed UNO detector

The next generation of neutrino detector is being considered for different locations within the US and will be at least 500 kTons in mass. Searches for evidence of proton decay, detection of neutrinos from supernovae, and detailed studies of neutrinos from man-made accelerators, are some of the physics measurements envisioned for such a detector.

Photograph of a 3x13x14 cm PbWO4 scintillation block with APDs from RMD and Hamamatsu.

In addition to their potential use as photodetectors for mega-ton neutrino detectors, the BNL group is also interested in the potential application of large area APDs to calorimetery measurements as part of the Rare Symmetry Violating Processes project at BNL. APDs can efficiently collect light from the solid-state inorganic scintillator calorimeters used in the KOPIO and MECO detectors. The amount of light collected is used to measure the energy of particles traversing these detectors.

This page is under construction