diff options
| -rw-r--r-- | src/detector.c | 4 | ||||
| -rw-r--r-- | src/ewald.c | 18 | ||||
| -rw-r--r-- | src/image.h | 5 | ||||
| -rw-r--r-- | src/main.c | 6 | ||||
| -rw-r--r-- | src/utils.h | 26 |
5 files changed, 56 insertions, 3 deletions
diff --git a/src/detector.c b/src/detector.c index ebcbb814..9e4e5649 100644 --- a/src/detector.c +++ b/src/detector.c @@ -29,11 +29,13 @@ void record_image(struct image *image) uint16_t counts; double val; double intensity; + double phac; val = image->sfacs[x + image->width*y]; + phac = image->phactors[x + image->width*y]; intensity = pow(val, 2.0); - counts = intensity*16; + counts = intensity * phac; image->data[x + image->width*y] = counts; diff --git a/src/ewald.c b/src/ewald.c index 9d8a0450..e9f36596 100644 --- a/src/ewald.c +++ b/src/ewald.c @@ -19,16 +19,30 @@ #include "cell.h" +/* Pulse energy density in J/m^2 */ +#define PULSE_ENERGY_DENSITY (30.0e7) + + void get_ewald(struct image *image) { int x, y; double k; /* Wavenumber */ + double i0fac; k = 1/image->lambda; + /* How many photons are scattered per electron? */ + i0fac = PULSE_ENERGY_DENSITY * pow(THOMSON_LENGTH, 2.0) + / image->xray_energy; + + printf("%e photons are scattered per electron\n", i0fac); + image->qvecs = malloc(image->width * image->height * sizeof(struct threevec)); + image->phactors = malloc(image->width * image->height + * sizeof(double)); + for ( x=0; x<image->width; x++ ) { for ( y=0; y<image->height; y++ ) { @@ -36,6 +50,7 @@ void get_ewald(struct image *image) double twothetax, twothetay, twotheta; double qx, qy, qz; + /* Calculate q vectors for Ewald sphere */ rx = ((double)x - image->x_centre) / image->resolution; ry = ((double)y - image->y_centre) / image->resolution; r = sqrt(pow(rx, 2.0) + pow(ry, 2.0)); @@ -51,6 +66,9 @@ void get_ewald(struct image *image) image->qvecs[x + image->width*y].u = qx; image->qvecs[x + image->width*y].v = qy; image->qvecs[x + image->width*y].w = qz; + + /* Calculate photon factor ("phactor") */ + } } diff --git a/src/image.h b/src/image.h index 35bd5da9..d5d5bb9c 100644 --- a/src/image.h +++ b/src/image.h @@ -62,6 +62,7 @@ struct image { uint16_t *data; double *sfacs; struct threevec *qvecs; + double *phactors; /* Radians. Defines where the pattern lies in reciprocal space */ double tilt; @@ -78,7 +79,9 @@ struct image { double resolution; /* pixels per metre */ /* Wavelength must always be given */ - double lambda; + double lambda; /* Wavelength in m */ + double xray_energy; /* X-ray energy + * in J (per photon) */ int width; int height; @@ -75,11 +75,15 @@ int main(int argc, char *argv[]) image.y_centre = 255.5; image.camera_len = 0.2; /* 20 cm */ image.resolution = 5120; /* 512 pixels in 10 cm */ - image.lambda = 0.2e-9; /* LCLS wavelength */ + image.xray_energy = eV_to_J(2.0e3); /* 2 keV energy */ + image.lambda = ph_en_to_lambda(image.xray_energy); /* Wavelength */ image.qvecs = NULL; image.sfacs = NULL; image.data = NULL; + /* Splurge a few useful numbers */ + printf("Wavelength is %f nm\n", image.lambda/1.0e-9); + get_diffraction(&image, cell); record_image(&image); diff --git a/src/utils.h b/src/utils.h index f1b72af8..1de0ea09 100644 --- a/src/utils.h +++ b/src/utils.h @@ -18,6 +18,20 @@ #include <math.h> + +/* Electron charge in C */ +#define ELECTRON_CHARGE (1.6021773e-19) + +/* Planck's constant (Js) */ +#define PLANCK (6.62606896e-34) + +/* Speed of light in vacuo (m/s) */ +#define C_VACUO (299792458) + +/* Thomson scattering length (m) */ +#define THOMSON_LENGTH (2.81794e-15) + + extern unsigned int biggest(signed int a, signed int b); extern unsigned int smallest(signed int a, signed int b); extern double distance(double x1, double y1, double x2, double y2); @@ -42,4 +56,16 @@ extern void mapping_rotate(double x, double y, double z, #define is_odd(a) ((a)%2==1) +/* Photon energy (J) to wavelength (m) */ +#define ph_en_to_lambda(a) ((PLANCK*C_VACUO)/(a)) + +/* Photon wavelength (m) to energy (J) */ +#define ph_lambda_to_en(a) ((PLANCK*C_VACUO)/(a)) + +/* eV to Joules */ +#define eV_to_J(a) ((a)*ELECTRON_CHARGE) + +/* Joules to eV */ +#define J_to_eV(a) ((a)/ELECTRON_CHARGE) + #endif /* UTILS_H */ |