PROCEDURE: 7s

TITLE: UV throughput (SBC)

CATEGORY: Calibration

PURPOSE: This procedure is for measuring the Absolute throughput of the
SBC at two wavelengths.

FREQUENCY: Once for each SBC filter that passes the light of Kr 1236\AA
(F122M, F115LP, F125LP, PR110L) and Xe 1469\AA (F115LP, F125LP, F140LP,
PR110L, PR130L)

DETECTOR: SBC

PREREQUISITES: SBC safe-open procedure 9s.

HARDWARE REQUIREMENTS: STUFF + Arc lamps

SOFTWARE REQUIREMENTS: 

COMMAND MODE: PSTOL

PROCEDURE/EXPOSURES:  
	1. Turn-on STUFF and the desired lamp. Put pinhole assembly in
           place.  Put desired SBC filter in place. 
	2. Put calibrated PMT in light path.
	3. Tune attenuation + lamp current for safe global 
	   count rate through filter with maximum throughput at line
	   wavelength, check with PMT read-out.
	4. Remove calibrated PMT.
	5. Take 120s tweak exposure.
	6. Adjust attenuation and/or lamp current to get count rate
           between 2e5 & 2.5e5 c/s.
	7. Put calibrated PMT in light path, record PMT read-out.
	8. Pinhole exposure: 500s 
	   (allows S/N = 10 to 11 per pixel over projected pinhole
	   spot). 
	9. Put calibrated PMT in light path, record PMT read-out.
	10. Dark exposure: 500s

VARIANTS:		a: Kr 1236 lamp + F122M 
			b: Kr 1236 lamp + F115LP
			c: Kr 1236 lamp + F125LP
			d: Kr 1236 lamp + F110L
			e: Xe 1469 lamp + F115LP
			f: Xe 1469 lamp + F125LP
			g: Xe 1469 lamp + F140LP
			h: Xe 1469 lamp + PR110L
			i: Xe 1469 lamp + PR130L

TOTAL EXPOSURES: 3

TOTAL TIME: setup + tweak + 3*overhead + 1120s = 0.74hr
	(setup = 10min, tweak = 10min, overhead = 2min)

ANALYSIS:
	(1) Subtract dark from 500s pinhole.
	(2) Determine total count-rate (dark subtracted).  Compare to
	    model expectation for mean PMT reading: calculate SBC
	    throughput.
	(3) Record ratio of PMT difference(after - before)/PMT mean.
	(4) Determine global dark rate, compare to previous long
	    darks. Note any significant differences. 
	(5) Determine number of hot pixels in dark, compare to previous
	    long darks.