Energy calibration of a PIN diode

– build the energy calibration dependency for PIN diode detector


– Radium-226 source
– PIN diode detector
– Crate CAMAC
– Intelligent controller
– High voltage power supply (HV)
– Amplifier
– Charge-to-digital converter (QDC)
– Vacuum station
– Vacuum gauge
– Computer
– Cables and accessories
Study the scheme of the experimental setup.
There are the structural elements of the experimental setup. Connect the PIN diode with the CAMAC modules in a proper way.
Connect the amplifier and the charge-to-digital converter by the cabel LEMO-LEMO in a proper way.
Switch ON the CAMAC crate.
Set CAMAC command N, A, F to read ADC. N A F
The working range for the input signal of a 12-bit charge-to-digital converter (QDC) lies in the range from 0 to 1 Volt. This range is divided into 212 = 4096 parts (channels). Thus, the amplitude of the input signal can be measured with an accuracy of ~ 1/4096 = 0.000244141 V.
The energy corresponding to the light peak in the energy distribution of 252Cf is ~ 102.5 MeV. In order to use the proposed QDC for measurement of energies in the range from 0 to 102.5 MeV, 102.5/4096 ~ 0.025 MeV/channel should correspond to 1 part (per 1 channel) of the QDC input range.
The reference source of alpha particles from 226Ra has a line with an energy of 7.687 MeV. When using this line to calibrate a spectrometer with the above mentioned energy range (from 0 to 102.5 MeV), the peak of alpha particles should fall at ~ 7.687/0.025 = 307 QDC channel.
Select the gain factor on the amplifier so that the peak of alpha particles from radium-226 with a maximum energy of 7.687 MeV falls as close as possible to the 307th channel.
There is the spectrum of radium alpha particles. Find centers of gravity of alpha-peaks. Move the blue and the red cursors to limit the area of the peak you wish to study and see "Mean value". Fill the table below with calculated values (round values to 1 decimal place).
Mean value 125.8 Mean value, channel Energy, MeV 4.784 5.489 6.002 7.687
Build the graph of the obtained dependency.
The obtained slope and intercept are the coefficients of the linear calibration of the energy scale of the PIN diode. Mean value, channel Energy, MeV 4.784 5.489 6.002 7.687