Component  Range  Notes  Data  Throughput Plots 
Si:As Detector  1.828  Boeing HF16128 BIB array specs sheet SiAs QE plot (Stapelbroek et al 1995) 
X_SiAs.dat 
Plot_SiAs.gif 
Sky Transmission  1.828  Mean PMV (Precipitable Water Vapor) measurements for Las Campanas have proved to be elusive. We assume that the PMV statistics for La Silla are representative for Las Campanas due to the similarity in location and altitude. Mean PMV values during the months of Aug 2001 (4.2mm) and May 2002 (5.8mm), suggest that 5mm is optimal. Sky transmission models come from Lord (1992) through the Gemini Observatory website. For our total transmission curve, we glue together the Lord (1992) curves for airmass = 1.5: 0.95.6um [3.0mm H20] and 628um [5.0mm H20]. We assume zero transmission from 5.66um, however this is irrelevant for the filters of interest to us. I can't find data for PWV > 3mm for the nearIR.  X_skytrans.dat 
MIRAC_skytrans.gif 
KRS5 window  1.828  6mm thick  however this matters little. The transmission from 130um is essentially flat, implying that the losses are completely dominated by reflection, not absorption. I calculated transmission as 12R, where R=(n1)^2/(n+1)^2, and n (refractive index) as function of wavelength is calculated with a 5thorder Sellmeier equation from an optics handbook. After a minor renormalization (to 0.716 @ 10um), the resulting reflectance vs. wavelength curve closely matched the curves seen in the literature and on the web.  X_KRS5.dat  MIRAC_KRS5.gif 
ZnSe window  1.828  A ZnSe window has been sometimes used instead of the KRS5 one. The properties and curve of ZnSe are shown at http://www.lure.upsud.fr/. Fortunately we have a scan of the transmission of the ZnSe window (J. Hora 4/9/90), so I digitized this plot. I assume the trans. @ 2.5um is the same blueward to 1.8um.  X_ZnSe.dat  MIRAC_ZnSe.gif 
KBr lens  1.828  KBr is extremely flat from 120mu (presumably dominated by reflection losses, not absorption), but absorption dominates redward of 20um. KBr transmission properties are discussed elsewhere by Janos Tech and Harrick optical material info. Multiple sources on the web claim transmission is 0.916 @ 10um. We digitize Fig. 727 (5.0mm KBr) from the Infrared Handbook and normalize to 0.916 @ 10um.  X_KBr.dat  MIRAC_KBr.gif 
Al mirror  1.828  I can't find Al reflectance redward of 10um. Table of reflectance (0.252.5um) is available on p. 25.15 of Handbook of Optics Vol. II. A rough, and crowded, reflectance curve is available (Fig. 743) of the Infrared Handbook. Values <2.5um come straight from Handbook of Optics. 2.510um curve is interpolated from IR Handbook curve, and normalized to 2.5um value from Handbook of Optics. Curve of 1028um is simply held constant at extrapolated 10um value.  X_Al.dat  MIRAC_Mirror.gif 
Au mirror  1.828  I can't find Au reflectance redward of 10um. Table of reflectance (0.252.5um) is available on p. 25.15 of Handbook of Optics Vol. II. A rough, and crowded, reflectance curve is available (Fig. 743) of the Infrared Handbook. Values <2.5um come straight from Handbook of Optics. IR Handbook shows reflectance to be flat and constant between 2.510um. We keep constant reflectance (0.977) for 2.528um.  X_Au.dat  MIRAC_Mirror.gif 
BaF2 Blocking Filter (1mm)  1.828  This curve should not be necessary for any calculation  all of the OCLI silicate filters already have blocking filters included in their curves! An optical handbook gave transmission curves for 10mm and 27mm thickness BaF2 filters. We use a published Sellmeier equation to determine the reflective losses, then calculate the absorption coefficient from the remaining measured transmission (12*R), and extrapolate for 1mm thickness. The response dives at 14um since the 10mm curve reaches zero at this point. The veracity of this feature is of no consequence since we don't use the blocking filter redward of 12um.  X_BaF2_1mm.dat 
Slot Letter 
Filter (Width %) 
Notes  Transmission Data (Temperature given in file name)  
A  2.2K (16%)  "W022067" is the only Kband curve found [2.206um, 16.0%, Amb]. Ambient curve used here.  X_OCLI_K_2.2_Amb.dat  
B  3.8L (16%)  There are two curves which may be correct: "OCLI Astronomy L" [3.841, 16.2%, 77K] and anonymous [3.830, 16.6%, 77K]. The "OCLI Astro L" appears to be the better match, and it is the only 3.8um filter curve shown in the old "MIRAC Instruction Manual" and Hora's thesis. Only the 77K curve is available, and the type of substrate is unknown.  X_OCLI_L_3.8_77K.dat  
C  4.8M (16%) 
The best match is "OCLI W049318" [4.93, 16.4%; Silicon substrate] (Hoffmann MIRAC filter list 4/12/95 & 2/24/94). A W049448 filter is mentioned in HoffmannOrton fax dated 6/30/95, which was bought along with the "Astro M", however no curve for W049448 was found. I can find only a transmission profile measured at ambient, so no temperature correction has been applied. NOT "OCLI Astronomy M" [4.72, 11.7%]. NOT W047114 [4.71, 12.8%] mentioned in Hora thesis. 
X_OCLI_W049318_Amb.dat 

E  8.8 (10%)  Unambigously "OCLI Astronomy O". Both 77K and Ambient curves available. Extrapolation to 5K suggests a 2.96% shift in wavelength from the Ambient curve. Here, we take the 77K curve and multiply wavelength by 0.992393 and transmission by 1.017211. Both the filter and CaF2 blocker are included in the curve.  X_OCLI_O_8.8_5K.dat  
F  9.8 (10%)  Unambigously "OCLI Astronomy P" [9.80, 9.7%]. Both 77K and Amb curves are available. Extrapolation to 5K suggests a 2.67% shift in wavelength to the Ambient curve. Here, we take the 77K curve and multiply wavelength by 0.993165 and transmission by 0.997469. The OCLI W09529 [9.57, 44.0%] can be safely excluded as a match. Both the filter and BaF2 blocker are included in the curve.  X_OCLI_P_9.8_5K.dat  
G  10.3 (10%)  Unambigously "OCLI Astronomy Q" [10.29, 9.8%]. Both 77K and Amb curves are available. Extrapolation to 5K suggests a 2.47% shift in wavelength to the Ambient curve. For a 5K curve, we take the 77K curve and multiply wavelength by 0.993745 and transmission by 1.017211.  X_OCLI_Q_10.3_5K.dat  
H  10.6N (8.113.1) 
10.6W = 10.6N = W107738 (8.0813.08; "8" = silicon substrate) [defined in WH email 4/12/1995]. W107738 was bought by L. Deutsch from OCLI 3/94 [10.746, 47.15% @ Ambient] Note that a W105759 [10.58, 45.8%] exists, which is similar. I can find only a transmission profile measured at ambient, so no temperature correction has been applied. 
X_OCLI_W107738_Amb.dat  
I  11.7 (10%)  "OCLI Astronomy R" [11.70, 9.5%, 77K] is clearly the correct filter. Both the filter and BaF2 blocker are included in the curve. The Ambient and 77K curves suggest a correction of 2.71% to the Ambient wavelength scale to correct for 5K. Here, we multiply the wavelength of the 77K curve by 0.993067 and the transmission by 1.040762.  X_OCLI_R_11.7_5K.dat  
J  12.5 (10%)  Unambigously "OCLI Astronomy S" [12.49, 9.3%]. Both 77K and Amb curves are available. Extrapolation to 5K suggests a 2.64% shift in wavelength to the Ambient curve. For 5K curve, we take 77K curve and multiply wavelength by 0.993276 and transmission by 1.011623. Both the filter and BaF2 blocker are included in the curve.  X_OCLI_S_12.5_5K.dat  
M  18.0 QS (10%)  "Q short"  explicitly called "QS" in the MIRAC menu, with the widest bandwidth among the OCLI Qband filters. Only ambient curve is given  no temperature correction is given. [17.504, 10.62%]  X_QS_Amb.dat  
N  18.5 M18 (7.0%)  Unambigously the Michelle M185B7 filter, 25K [18.29, 8.3%] and 300K [17.97, 11.1%] curves available. I've adopted the 25K curve.  X_M185B7_25K.dat  
P  20.9 M20 (16.625.2)  Unambigously the Michelle M209B42 filter. 25K [20.68, 37.4%], 77K, 160K, 235K, and 300K [19.84, 43.2%] curves are available. The 25K curve is adopted here.  X_M209B42_25K.dat  
Q  24.5 M24 (7.8%)  Unambigously the Michelle M245B5 filter. 25K [24.56, 7.9%] and 290K [24.85, 7.8%] filter curves are available. The 25K curve is adopted here.  X_M245B5_25K.dat 