PHOTON COUNTING HEAD H12775 OVERVIEW The H12775 is a photon counting head device containing of a 10-mm (1/2") diameter head-on photomultiplier tube, along with a high-speed photon counting circuit and a high-voltage power supply circuit. The high voltage supply for photomultiplier tube and the discrimination level are preset to optimum values, allowing photon counting measurement by just connecting a +5 V supply. The H12775 has a function of over light detection output for indicating the excessive light operating condition. PRODUCT VARIATIONS Type No. H12775 Photocathode Bialkali Window material Borosilicate glass Features For visible range This product can’t be used at vacuum environment or reduced pressure environment. SPECIFICATIONS Parameter Input voltage Max. input voltage Max. input current Effective area Peak sensitivity wavelength 300 nm 400 nm Count sensitivity 500 nm 600 nm Count linearity *1 Dark count *2 Pulse-pair resolution Output pulse width Load resistance 50 Ω Output pulse height Un-terminated Recommended load resistance Signal output logic Over light High level detection output *3 Low level Operating ambient temperature *4 Storage temperature *4 Weight *1: Random pulse, at 10 % count loss *2: After 30 minutes storage in darkness Subject to local technical requirements and regulations, availability of products included in this promotional material may vary. Please consult with our sales office. Information furnished by HAMAMATSU is believed to be reliable. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications are subject to change without notice. No patent rights are granted to any of the circuits described herein. ©2017 Hamamatsu

PHOTON COUNTING HEADS H12775 Figure 1: Count sensitivity Figure 2: Dark count Figure 3: Output waveform OUTPUT PULSE HEIGHT (1 V/div.) Figure 4: Count rate linearity and over light detection output Figure 5: Count rate linearity correction TPMOB0218EA OUTPUT COUNT 108 107 106 OVER LIGHT DETECTION OUTPUT Linearity correction formula N : real count rate (s-1) M : measured count rate (s-1) t : pulse pair-resolution (s) RELATIVE INPUT LIGHT Figure 6: Block diagram AMPLIFIER PULSE COMPARATOR SHAPER TO PULSE COUNTER POSITIVE LOGIC L.L.D. HIGH VOLTAGE POWER SUPPLY CIRCUIT OVER LIGHT DETECTION OUTPUT...