1 Introduction

Radiations of varied degrees cause and induce many Physico-chemical changes in the materials that come into contact with them in the environment. Radiations influence various materials by varying degrees, depending on the type of radiation, radiation dosage level, exposure time, material characteristics, environmental conditions, etc. (Chandrappa et al. 2021; Aly et al. 2015). Radiation dosimetry is the main point of much research due to the use of radiation in various applications(Baccini, et al. 2019; Andreo, et al. 2017). A dosimeter is any instrument that can produce an output value that represents the average absorbed dose deposited in its sensitive volume by ionizing radiation(Baccini, et al. 2019; Chu, et al. 2008). What's needed is a system that's simple to be used and set up, and that can detect radiation in real-time and from far distances. It also needs to be long-lasting and cost-effective.

Polymers with excellent surface and bulk properties have grown in relevance significantly over the last few decades due to their low weight, low cost, easy processability, and ease of fabrication of thick and thin samples. PVA (Poly-Vinyl Alcohol) is a polymeric substance with a wide range of applications. This is due to their great optical properties, lightweight, and mechanical properties, as well as the fact that they are an excellent host material for composites(Hadi Al-kadhemy et al. 2014; Ali Omer and Ali Bashir 2018). Most PVA works have composites that are sensitive to low or high-energy radiations, resulting in improved or degraded physicochemical qualities (Chandrappa et al. 2021; Hadi Al-kadhemy et al. 2014; Ibrahim et al. 2021; Mir et al. 2016; Sharaf et al. 1995; Al-Kadhemy and Abass 2013; Raghuvanshi et al. 2012; Antar 2014).

When high-energy radiation (i.e., X-rays, \(\gamma\)-rays, etc.) interacts with polymeric materials, it causes chain scission. This results in a decrease in molecular weight, and inter/intermolecular cross-linking. This also results in an increase in molecular weight, emission of atoms, molecules, and molecular fragments, free radical formation, and the production of reactive oxygen species (ROS). All of this eventually leads to degradation, color change, brittleness, hardness, etc. Where, the optical, thermal, mechanical, dielectric, and conductivity properties of radiation-exposed composite materials could be fine-tuned as a result of these structural alterations (Chandrappa et al. 2021; Raouafi et al. 2018). Many scientists have been studying the impact of irradiation on doped polymer composite materials to investigate their unique features (Hadi Al-kadhemy et al. 2014; Ali Omer and Ali Bashir 2018; Al-Kadhemy and Abass 2013).

Gamma-Ray radiation dosimetry at the micro and the nanoscale is required for medical and industrial applications such as microbeam radiation treatment, microelectronics, and radio-synthesis of nanomaterials(Archer et al. 2019; Chmielewska 2017; Zimek 2017). Different techniques, such as the oscillometric readout method, the Gafchromic method, the spectrophotometric readout method, and optical methods, can be used to determine the gamma-ray radiation dose (Ibrahim et al. 2021). Based on the radiation effects, the optical approaches for radiation dose monitoring can be divided into four types. The first type is based on the radiation-induced luminescence and thermoluminescence effect (Ali Omer and Ali Bashir 2018; Rozaila et al. 2016; Afifi 2021). The second type is based on the radiation-induced attenuation (RIA) effect (Cai et al. 2017; Kashaykin et al. 2019; Kashaykin et al. 2015). The third type is based on varying the frequency of the Brillouin scattering in the distributed optical fibers (Alasia, et al. 2005). The final type is based on photonic crystal fiber and Bragg gratings structures (Baccini, et al. 2019). Photonic crystals (PhCs) have recently gained prominence in a variety of applications such as optical fibers, sensors, and biomedical devices (Entezam et al. 2016; Elsayed et al. 2021; Sayed et al. 2022). Photonic band gaps (PBGs) are a key and unique feature of PhCs that prevent light from propagating at particular frequency intervals, which come from destructive interference of the PhC's constituent materials. Reference (Bijalwan et al. 2021) study the sensing performance of a one-dimensional photonic crystal (PC) based sensor for the detection of blood plasma and cancer cells. Reference (Abohassan et al. 2021) create an effective sensor based on a one-dimensional binary photonic crystal for detecting the fat content in commercial milk. Reference (Qutb et al. 2021) using a 1D-defective photonic crystal structure, show the sensing concept for concurrently detecting the salinity and temperature of seawater. Reference (Sabra, et al. 2022) In the mid-IR range, the 1D-PhC was introduced as an optical pressure sensor.

Polymers, metals, semiconductors, liquid crystals, superconductors, metamaterials, and dielectrics are all utilized in the design of PhCs (Hadi Al-kadhemy et al. 2014; Elsayed et al. 2021; Wu 2021; Iwamoto et al. 2021; Park et al. 2021). The incorporation of porous silicon (PSi) layers in PhCs as a novel sensor design to improve sensitivity is the focus of recent research (Ivanov et al. 2022; Van 2022). PSi layer is commonly fabricated by an electrochemical etching route. Due to its simplicity of manufacture, different pore sizes and morphologies, vast surface area, and controlled surface modification and reactivity, it is highly recommended and considered to be a promising candidate (Al-Syadi et al. 2021; Yue et al. 2019; Zhong et al. 2020; Zaky and Aly 2021).

In this work, we develop a highly sensitive radiation dosimeter; 1D-PhC based on PSi layers infiltrated by PVA-polymer doped with crystal violet (CV) and carbol fuchsine (CF) dyes. Also, we studied the behavior of this structure when exposed to different doses of gamma rays emitted from a 60Co-radioactive source. In addition, the results show how the PSi-layer enhanced the optical properties of the doped PVA-Polymer, and how the porosity of PSi-layers affects our structure. Then, the effect of gamma-ray doses ranging from 0 to 70 Gy on our structure is studied. Finally, the effect of thicknesses of the two layers on our structure and how much they affect the sensitivity of this radiation-dosimeter are discussed.

2 Theoretical framework

In this part, we design a gamma-ray dosimeter by a 1D-PhC based on the Porous Si layer. As shown in Fig. 1, the structure is configured as [Air (PSi1/PSi2) N1 substrate]. Where, PSi1, PSi2 are the first and second porous silicon layers with porosity P1, P2, respectively, and N1 represents the number of periods. For gamma-ray detection, we used PSi-layer to be infiltrated by the doped PVA-Polymer. The transfer matrix method (TMM) is used to study the transmittance spectra of our structure (Ahmed and Mehaney 2019; Aly and Sayed 2020; Aly et al., 2009; Aly and Mohamed. 2015).

Fig. 1
figure 1

Schematic diagram of a 1D-Binary PhC gamma-ray dosimeter. The structure of 1D-PhC is surrounded by air and glass substrate and the number of periods = 20

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As a result, the Porous Silicon layer, the doped PVA-Polymer, and the transfer matrix method are the main points to illustrate our theoretical study.

2.1 Optical properties of the porous silicon layer

The optical refractive index of the PSi layer (nPSi) that is filled with Polymer (nPolymer) with porosity (P) is calculated using Bruggeman's effective medium equation (Zaky and Aly 2021; Ahmed and Mehaney 2019).

$${\mathrm{n}}_{(\mathrm{PSi})}=0.5\sqrt{\in +\varphi }$$
(1)
$$\upepsilon =3\mathrm{P}\left({{\mathrm{n}}_{\left(\mathrm{Polymer}\right)}}^{2}-{{\mathrm{n}}_{\left(\mathrm{Si}\right)}}^{2}\right)+\left(2{{\mathrm{n}}_{\left(\mathrm{Si}\right)}}^{2}-{{\mathrm{n}}_{\left(\mathrm{Polymer}\right)}}^{2}\right)$$
(2)
$$\varphi =\sqrt{{{\upepsilon }^{2}+(8}^{2}{{\mathrm{n}}_{\left(\mathrm{Si}\right)}}^{2}{{\mathrm{n}}_{\left(\mathrm{Polymer}\right)}}^{2})}$$
(3)

where, \({n}_{(Si)}\) is the refractive index of the silicon, and is equal to 3.7 (Elsayed et al. 2021).

2.2 Optical properties of the PVA-polymer

The film samples of the (PVA/CV + CF) polymer were prepared by using a solvent casting method. These films were irradiated At room temperature with gamma-ray doses of 0–70 (Gy) emitted from 60Co-source (Antar 2014).

The refractive index of the (PVA/CV + CF) polymer is given as a function of wavelength and gamma-ray radiation doses Dγ (Gy) by fitting the experimental results using the Matlab program (Antar 2014). Applying the cubic fitting to the experimental data, the following fitted equations can be used to express the refractive index of the polymer as follows.

$$\mathrm{n}(\mathrm{D})=\mathrm{A}{\uplambda }^{3}+\mathrm{B}{\uplambda }^{2}+\mathrm{C\lambda }+\mathrm{D}$$
(4)

where, A, B, C, and C are the fitted coefficients and are listed in Table 1. The R-square value of the fitting is equal that the value of 0.015963 through gamma-ray radiation doses ranging from 0 (unirradiated sample) to 70 Gy.

Table 1 Constants of the refractive index of the (PVA/CV + CF)-Polymer are given as a function of wavelength at different gamma-ray doses (Gy)
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2.3 Transfers matrix method (TMM)

The transfer matrix method (TMM) is used to determine the optical properties of the presnt structure (transmittance, reflectance, and absorbance spectra) because of electromagnetic waves interaction with our structure. Many previous studies have investigated the details of TMM (Elsayed et al. 2021; Sayed et al. 2022; Zaky and Aly 2021; Aly et al. 2022; Abadla et al. 2021; El-Shemy et al. 2022; Mehaney et al. 2019; Mehaney 2019). The following matrix (M) represents the total transfer matrix for the proposed structure with the number of periods (N1) of PSi1 and PSi2-layers:

$$M=({M}_{{PSi}_{1}}{M}_{{PSi}_{2}}{)}^{{N}_{1}}=\left(\begin{array}{cc}{m}_{11}& {m}_{12}\\ {m}_{21}& {m}_{22}\end{array}\right)$$
(5)

Then, the transmittance spectra of our structure could be described according to the previous matrices as: -

$$T=\frac{{P}_{s}}{{P}_{o}}{\left|t\right|}^{2}=\frac{2{P}_{o}}{({m}_{11}+{m}_{12}{P}_{s}){P}_{o}+{m}_{21}+{m}_{22}{P}_{s}}$$
(6)

where, \({P}_{o},{P}_{s}\) are the propagation matrix of air and substrate for TE-polarization, respectively.

3 Results and discussion

Herein, the numerical results of our 1D-PhC gamma-ray dosimeter based on PSi-layer are discussed in this section. These results include the transmittance spectra of our structure in the visible region for a transverse electric (TE) polarization. The refractive indices of Si, air and glass are nSi = 3.7, nAir = 1, and ns = 1.52, respectively (Zimek 2017). The refractive index of the PSi and Polymer are mentioned in Eqs. (1) and (4). By injecting the polymer at the top of the structure, the pores will be infiltrated with the polymer as shown in Fig. 1. The thickness of the first layer (PSi1) and the second layer (PSi2) are d1 = 30 nm, and d2 = 73 nm with porosity of P1 = 20%, P2 = 80%, respectively. Furthermore, the period of numbers is N1 = 20.

The first point in this section explains the effect of radiation on the dimension of our radiation dosimeter and the reason for choosing these materials. The radiation damage is critical for devices that operate in radiation-prone environments. Wherein, radiation dosimeters are exposed to pressure, temperature, or strain from external sources during Gamma-radiation. The reason behind choosing Si material is that the refractive index of Si changes below (5 × 10–5) at (Dγ = 1000 kGy). Also, the thermo-optic coefficient of Si is equal (2.3 × 10–4) at (Dγ = 66.5 kGy, and 32 °C) (Baccini, et al. 2019; Cocorullo et al. 2002). And the maximum rise in the temperature of Si is equal to (3.2 °C) due to the radiation effect. Besides, the thermal expansion coefficient of the Si is very small and equals (≈ 2.6 × 10–6)(Okada and Tokumaru 1984). Therefore, the change in the refractive index of Si caused by the radiation processes across a γ-dose range from 0 to 70 Gy can be ignored. Additionally, the effect of radiation on the geometrical dimensions (thermal expansion) of the proposed sensor (radiation dosimeter) is ignored. The thermal strain caused by radiation can thus be ignored (Ibrahim et al. 2021). To sum up, we think the proposed structure is suitable for measuring gamma rays without being destroyed.

For, the effect of radiation on the refractive index of the (PVA/CV + CF) polymer is shown in Fig. 2. The fitting of the experimental results examined in reference(Antar 2014) is discussed in this figure. Based on this figure, the fitting parameters in Table 1 are calculated. Through the varied values of Dγ (Gy), the figure demonstrates a sufficient matching with the experimental results. This indicates that the fitting process produces the same results as the experimental data, and the fitting parameters are suitable for calculating the (PVA/CV + CF) polymer's refractive index.

Fig. 2
figure 2

The response of the refractive index of PVA-Polymer doped with CV + CF to the Gamma-Ray radiation variation based on the fitting of the experimental data(Antar 2014)

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Figure 2, shows the (PVA/CV + CF) refractive index for unirradiated and irradiated polymer in the range (10–70 Gy) γ-ray doses from wavelength 380 nm to 550 nm. The refractive index reduces gradually as the wavelength increases, and the changes become larger as the wavelength increases. Whereas crystallization, density, electronic structure, and defects are all potential causes for changes in the refractive index induced by γ-radiation (Antar 2014). The refractive index increases with doses of irradiation, as shown in Fig. 2; for example, when doses irradiation increases from 0 to 70 Gy, the n changes from 2.24 to 2.40 at the wavelength (λ = 555 nm). The increase in the polymer's refractive index after irradiation could be due to ionization, and/or atomic displacements caused by a gamma-ray collision with the samples, which could alter the internal structure of the polymer films (Antar 2014).

Figure 3, shows the effect of the porous silicon on the refractive index of the doped polymer (PVA/CV + CF), and the effect of porosity on the refractive index of the porous silicon infiltrated by the doped polymer [PSi (PVA/CV+CF)]. As shown in Fig. 3a, the porous silicon material enhanced the refractive index of the doped polymer [n (PSi (PVA/CV+CF))]. Indeed, the refractive index increased from 2.53 to 2.82 at λ = 400 nm, and from 2.25 to 2.63 at λ = 560 nm, respectively. According to Bruggeman’s effective-medium approximation as Eq. (1), the refractive index of porous silicon depends on the refractive index of silicon and the refractive index of the material inside the pores. So, any change in the refractive index of the material inside the pores, reflects on the refractive index of porous silicon material. This is the essential point on which our gamma-ray dosimeter is based. Whereas any change in the refractive index of doped polymer induced by γ-radiation will reflect on the refractive index of the material. In addition, the refractive index of porous silicon depends on the porosity value, as shown in Eq. (1). Figure 3b, shows the dependence of the refractive index of [PSi (PVA/CV+CF)] on the variation of porosity. The refractive index of [PSi (PVA/CV+CF)] decreases with an increase in the porosity value from λ = 350 nm to λ = 690 nm, then increases with an increase in the porosity value for λ > 690 nm. The refractive index equals 3.12, 2.82, and 2.69 for P = 30%, 65%, and 80% at λ = 400 nm. Figure 4, shows the effect of γ-doses in the range (0–70 Gy) on the refractive index of [PSi(PVA/CV+CF)] with porosity equal to 65%. The refractive index firstly slightly increases with the increase in the γ-ray doses and then decreases with the increase in the γ-ray doses in all wavelength ranges.

Fig. 3
figure 3

a The difference between the refractive index of (PVA/CV + CF) and refractive index of PSi (PVA/CV + CF) at zero Gy, with a Porosity of 65%. b The Effect of Porosity on the refractive index of [PSi (PVA/CV+CF)] at zero Gy

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Fig. 4
figure 4

The effect of the gamma-ray radiation on the refractive index of [PSi (PVA/CV+CF)] at a porosity of 65%

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Figure 5, represents the transmittance spectra of our proposed structure of the gamma-ray dosimeter for TE-modes calculated by the TMM method. The initial geometrical parameters of this structure are set as d1 = 30 nm, and d2 = 73 nm with porosity P1 = 20%, and P2 = 80%, respectively, and N1 = 20. The photonic bandgap (PBG) appears in the visible range with the left side wavelength (λL = 527.5 nm), right side wavelength (λR = 678.7 nm), and the width of PBG equal (\(\Delta \lambda ={\lambda }_{L}-{\lambda }_{R}=151.2 nm\)). The principle behind this structure is that the PBG works as a sensor for gamma-ray radiation. When the structure is exposed to gamma-ray radiation, the refractive index of materials will be changed and then the PBG will change as well. Before showing the effect of gamma-ray radiation on the PBG, we are doing optimization for the parameters of this structure.

Fig. 5
figure 5

Transmittance spectra of 1D-Binary structure with thickness d1 = 30 nm, d2 = 73 nm, N-period = 20, and porosity of P1 = 20%, P2 = 80% at zero gamma-ray radiation

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Figure 6, shows the transmittance spectra of our structure at the different number of periods. We note that the PBG became sharper and steeper as the number of periods increased. In addition, there is no change in the transmission spectra of this structure, and the width of the PBG doesn’t affect by increasing the number of periods. In other words, we choose N1 = 35 in the following calculation to the PBG become more suitable for the detection of gamma-ray radiation.

Fig. 6
figure 6

Transmittance spectra of 1D-Binary structure with thickness d1 = 30 nm, d2 = 73 nm, and porosity P1 = 20%, P2 = 80% at zero gamma-ray radiation at different N-period

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Figure 7, shows the effect of porosity of the first and the second layer of our structure on the PBG sensor. As shown in Fig. 7a, b with the increase in the porosity of the first layer (P1) and the second layer(P2), the width of the PBG decreases. We choose P1 = 30% and P2 = 85% for the width of the PBG to appear in a wide and suitable form. Because the primary focus of this study is on the development of radiation-resistant FBGs for use in nuclear environments in temperature and strain measurement applications.

Fig. 7
figure 7

The effect of the porosity on the photonic bandgap of our design for TE at d1 = 30 nm, d2 = 73 nm, N = 35, at zero gamma-ray radiation. a For the porosity of the first layer, b For the porosity of the second layer

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Now, we show the effect of γ-doses (Gy) from (0–70 Gy) on the PBG sensor of our radiation dosimeter, as shown in Fig. 8a. It can note that with an increase in the value of γ-doses (Gy), the left side of the PBG shifts to a higher wavelength, and the width of the PBG is affected by this radiation. This shift is due to the change in the refractive index of the Psi-layer which is induced by gamma-ray radiation.

Fig. 8
figure 8

a The effect of gamma-ray radiation on transmittance spectra of our structure with a thickness of d1 = 30 nm, d2 = 73 nm, porosity P1 = 30%, P2 = 85%, and N-Period = 35. b The left edge side of PBG and the sensitivity at different γ-doses (Gy) from (0–70 Gy)

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We examine the performance of our radiation dosimeter by calculating the sensitivity of the dosemeter. The sensitivity (S) is defined as the difference in the wavelength (\(\Delta {\lambda }_{L}\)) to the difference in the refractive index of doped PVA-polymer and units of (nm/RIU), as the following Eq. (7).

$$S=\frac{\Delta {\lambda }_{L}}{\Delta {n}_{(Polymer)}}$$
(7)

Figure 8b, shows the effect of γ-doses (Gy) on the left band side of the PBG \(\left({\lambda }_{L}\right)\) and the sensitivity of this radiation dosimeter. We noted that with an increase in γ-doses from (10 Gy) to (70 Gy), the \(\left({\lambda }_{L}\right)\) an increase from (521.3 nm) to (536.7 nm), and the sensitivity decrease from (176.5 nm/RIU) to (133.3 nm/RIU). We will study the geometrical parameters that will maximize the shift of the PBG's left band side, and therefore sensor sensitivity, under various radiation doses. The effect of thickness of the first layer PSi1 with values of (33, 35, 38, and 40 nm) at different γ-doses (Gy) on the PBG and sensitivity of this will be studied, while the other parameters are kept constant. As shown in Fig. 9a, b, c, and d, generally, it noted that with an increase in the thickness of the first layer, the left side of the PBG an increase and shift to longer wavelengths at the same value of γ-dose (Gy). Eg; At γ-dose is equal (10 Gy), with an increase of d1 (33, 35, 38, and 40 nm), the \(\left({\lambda }_{L}\right)\) increase with values (534.3, 543.5, 559.1, and 571.6 nm), respectively. In addition, at each value for this thickness, we study the effect of γ-doses (Gy), and we noted that the \(\left({\lambda }_{L}\right)\) shifted to higher wavelengths with an increase in the value of γ-doses (Gy). Then, we study the sensitivity of the different thicknesses of the first layer at different γ-doses (Gy), as shown in Fig. 10. We conclude from Fig. 10 that, when the thickness of the first layer equals the value of 38 nm, our radiation dosimeter gives sensitivity with very high stability and equals ≈ 195 nm/RIU. Consequently, the thickness of the first layer is taken as 38 nm.

Fig. 9
figure 9

The effect of the thickness of first layer PSi1 (PVA/CV+CF) on the properties of our design for TE at d2 = 73 nm, N1 = 35, and porosity P1 = 30%, P2 = 85% at γ-doses (Gy) from (0–70 Gy)

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Fig. 10
figure 10

The effect of the thickness of first layer PSi1 (PVA/CV+CF) on the sensitivity of our design for TE at d2 = 73 nm, N1 = 35, and porosity P1 = 30%, P2 = 85% at γ-doses (Gy) from (0–70 Gy)

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Secondly, we study the effect of the thickness of the second layer PSi2 with values (72, 74, 76, and 77 nm) at different γ-doses (Gy) on the PBG and the sensitivity of this radiation dosimeter. The effect of the thickness of the second layer gives the same behavior as the first layer. As shown in Fig. 11a, b, c, and d, at γ-dose is equal (10 Gy), with an increase of d2 (72, 74, 76, and 77 nm), the \(\left({\lambda }_{L}\right)\) increase with values (554.6, 563.9, 575.1, and 581.6 nm), respectively. With an increase in the value of the γ-doses (Gy) at each value of the thickness of the second layer, the \(\left({\lambda }_{L}\right)\) shifted to higher wavelengths. The sensitivity at each thickness of the second layer and at different values of the γ-doses (Gy) was studied as shown in Fig. 12. We note that at each value of the thickness of the second layer, with the increase in the value of the γ-doses (Gy), the sensitivity gradually increases. When the thickness of the second layer equals the value of 72 nm, the sensitivity is characterized by very high stability at each of the applied γ-doses (Gy) and equals ≈186 nm/RIU. Therefore, the thickness of the second layer is taken as 72 nm.

Fig. 11
figure 11

The effect of the thickness of second layer Psi2 (PVA-Polymer) on the properties of our design for TE at d1 = 38 nm, N = 35, and porosity of P1 = 30%, P2 = 85% at γ-doses (Gy) from (0–70 Gy)

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Fig. 12
figure 12

The effect of the thickness of second layer Psi2(PVA-Polymer) on the sensitivity of our design for TE at d1 = 38 nm, N = 35, and porosity P1 = 30%, P2 = 85% at γ-doses (Gy) from (0–70 Gy)

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The relation between the left side of the PBG and the γ-doses (Gy), in addition to the relation between the sensitivity and the γ-doses (Gy) at the optimized parameters, is given by the following equations based on the data fitting in the form of the 4th-degree polynomial:

$$S=3.7062\times {10}^{-6}{{D}_{\upgamma }}^{4}-0.00058481 {D}_{\upgamma }^{3}+ 0.029151{D}_{\gamma }^{2}-0.36176{D}_{\upgamma }+180.6,$$
$$\mathrm{R}= 0.84006$$
(8)
$${\lambda }_{L}=2.4793\times {10}^{-6}{{D}_{\upgamma }}^{4}-0.00029159 {D}_{\upgamma }^{3}+ 0.0094989{D}_{\gamma }^{2}+0.29031{D}_{\upgamma }+550.99,$$
$$1\mathrm{ R}= 0.84006$$
(9)

Finally, a comparison between our study and previous experimental radiation dosimeter used is shown in Table 2. This table shows firstly the proposed gamma-ray dosimeter based on 1D-photonic crystals and using porous silicon layers is a unique study and did not exist before. Furthermore, this radiation dosimeter achieved the highest sensitivity of 186 nm/RIU compared to published results in this part with very stability along the range of visible wavelengths when the design is exposed to gamma-ray doses from 0 to 70 Gy.

Table 2 A comparison between our design and previous radiation dosimeters
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4 Conclusion

We developed a highly sensitive 1D-PhC radiation dosimeter based on PSi-layers infiltrated by PVA-polymer doped with crystal violet (CV) and carbol fuchsine (CF) dyes. The theoretical analysis is investigated by fitting the experimental data of the doped PVA-polymer, the Bruggeman's effective medium equation of PSi-layer, and the transfer matrix method for calculating the optical properties of the dosimeter structure. The numerical results demonstrated that the PSi-layers enhanced the refractive index of the doped PVA-Polymer. In addition, they illustrated the idea of this radiation dosimeter is based on the shift in the PBG when it is exposed to gamma-ray radiation. Physically, this shift is due to the refractive index of doped PVA-Polymer depending on the γ-doses (in Gy unit). Therefore, the refractive index of PSi-layers is changed when exposed to γ-doses. The novelty of this pepper lies in the fact that this radiation dosimeter achieved a high sensitivity of 186 nm/RIU with very stability along of the range of visible wavelengths when the design is exposed to gamma-ray doses from 0 to 70 Gy. Furthermore, the effects of the thickness of the PSi-layers are studied to achieve the highest sensitivity. To the author's knowledge, this is the first time 1D-PhC based on PSi-layers has been used as a gamma-ray dosimeter. Finally, the other purpose of this radiation dosimeter is to be used as radiation-resistant FBGs for usage in nuclear environments in temperature and strain measurement applications.