An electronic device includes an electronic component and a heat dissipating casing configured to dissipate heat from the electronic component. The switch member is connected to a driven shaft, and the driven shaft is connected to a brake member. Desirable properties for a downhole detector include; high temperature operation, reliablerobust packaging, good resolution, high countrate capability, high density, high Z, low radioactive background, low neutron cross-section, high light output, single decay time, efficiency, linearity, size availability, etc. At the second time or later chances of escaping, an actual escaping occurs to generate an indirect escaping light.