diff --git a/scopesim/effects/spectral_efficiency.py b/scopesim/effects/spectral_efficiency.py
index 4798a86d..6261a567 100644
--- a/scopesim/effects/spectral_efficiency.py
+++ b/scopesim/effects/spectral_efficiency.py
@@ -38,9 +38,9 @@ def get_efficiencies_from_file(self, fname):
         for hdu in hdul[2:]:
             name = hdu.header['EXTNAME']
             lam = hdu.data['wavelength'] * u.um   # check units explicitely
-            trans = hdu.data['transmission']
-            effic = TERCurve(wavelength=lam, transmission=trans)
-            efficiencies[name] = effic
+            efficiency = hdu.data['efficiency']
+            effic_curve = TERCurve(wavelength=lam, transmission=efficiency)
+            efficiencies[name] = effic_curve
 
         hdul.close()
         return efficiencies
@@ -76,10 +76,7 @@ def apply_to(self, obj, **kwargs):
             wave_cube = (wave_cube * u.Unit(wcs.wcs.cunit[0])).to(u.AA)
             print(wave_cube)
             print(effic.throughput(wave_cube))
-            np.savetxt(f"efficcurve_{trace_id}.txt", (wave_cube, effic.throughput(wave_cube)))
-            obj.hdu.writeto(f"before_{trace_id}.fits")
             obj.hdu = apply_throughput_to_cube(obj.hdu, effic.throughput)
-            obj.hdu.writeto(f"after_{trace_id}.fits")
         return obj
 
     def plot(self):
diff --git a/scopesim/effects/spectral_trace_list_utils.py b/scopesim/effects/spectral_trace_list_utils.py
index 5917f2a1..cf0f15c1 100644
--- a/scopesim/effects/spectral_trace_list_utils.py
+++ b/scopesim/effects/spectral_trace_list_utils.py
@@ -437,7 +437,6 @@ def __init__(self, fov, dlam_per_pix):
         #         add_cube_layer method
         cube_wcs = WCS(fov.cube.header, key=' ')
         wcs_lam = cube_wcs.sub([3])
-        fits.writeto(f"xilam_cube_{fov.meta['trace_id']}.fits", data=fov.cube.data)
         d_xi = fov.cube.header['CDELT1']
         d_xi *= u.Unit(fov.cube.header['CUNIT1']).to(u.arcsec)
         d_eta = fov.cube.header['CDELT2']
diff --git a/scopesim/tests/mocks/files/TER_grating.fits b/scopesim/tests/mocks/files/TER_grating.fits
index da324e81..42787cd1 100644
Binary files a/scopesim/tests/mocks/files/TER_grating.fits and b/scopesim/tests/mocks/files/TER_grating.fits differ